HomeMy WebLinkAbout20050927.tiff RESOLUTION
RE: APPROVE AMENDMENT#3 TO AGREEMENT FOR PROFESSIONAL SERVICES
AND AUTHORIZE CHAIR TO SIGN - MERRICK AND COMPANY
WHEREAS, the Board of County Commissioners of Weld County, Colorado, pursuant to
Colorado statute and the Weld County Home Rule Charter, is vested with the authority of
administering the affairs of Weld County, Colorado, and
WHEREAS, the Board has been presented with Amendment #3 to the Agreement for
Professional Services between the County of Weld, State of Colorado, by and through the Board
of County Commissioners of Weld County, on behalf of the Geographical Informational Systems
(GIS)Division,and Merrick and Company,with further terms and conditions being as stated in said
amendment, and
WHEREAS,after review,the Board deems it advisable to approve said amendment,a copy
of which is attached hereto and incorporated herein by reference.
NOW,THEREFORE, BE IT RESOLVED by the Board of County Commissioners of Weld
County,Colorado,that Amendment#3 to Agreement for Professional Services between the County
of Weld, State of Colorado, by and through the Board of County Commissioners of Weld County,
on behalf of the Geographical Informational Systems(GIS)Division, and Merrick and Company be,
and hereby is, approved.
BE IT FURTHER RESOLVED by the Board that the Chair be, and hereby is, authorized to
sign said amendment.
The abovaand foregoing Resolution was,on motion duly made and seconded, adopted by
t following
loing vote on the 14th day of March, A.D., 2005.
t \ E a
IG�; BOARD OF COUNTY COMMISSIONERS
WELD COUNTY, COLORADO
1861 4024
•
r r , •i William H. Jerke, Chair
Weld -o� � lerk to the Board
EXCUSED
BY: (;/M `
M. eile, Pro-Tem
Deputy Cle t tY P o the Board , 87 C
Davi Long AP V A \ % %
\
Robert D. Masden
ounny Att y
EXCUSED
Glenn Vaad
Date of signature: 1-I "
2005-0927
DP0014
C0 r. ESP., iJERRick 03a9 -DC
Contract No. 50-013137, Amendment No. 3
AMENDMENT NO. 3
to the
AGREEMENT FOR
PROFESSIONAL SERVICES
Between
Merrick & Company
and
Weld County, Colorado
2005-0927
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Contract No. 50-013137, Amendment No. 3
Amendment No. 2 to the Agreement for Professional Services
This is an Amendment to the Agreement for Professional Services ("Agreement") is made by and between
Merrick&Company, a Colorado corporation("Merrick") and Weld County, Colorado("County") signed
by the County on June 17, 1998. All of the terms and conditions found in the original Agreement apply to
this Amendment.
The following Attachments are incorporated into and made a part of this Agreement:
A- Statement of Services & Project Schedule
B - Schedule of Payment
C -Client Responsibilities
D - Documents and Deliverables Owned by Weld County
IN WITNESS WHEREOF,the parties execute this Agreement on the date last written below.
Weld County,Colorado Merrick& Company, a Colorado corporation
William H. Jerke, Chair Brian R. Raber, CMS
Board of County Commissioners
Signature Signature
Title eh14 -R. Roc C. Title Vice-President
Date - v' -c
E La
ATTEST:
1861 ilszp
WELD COON CL
DEPUTY CLE HE BOARD - 1,11
ATTESTING TO BOARD OF COUNTY
COMMISSIONER SIGNATURES ONLY
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Contract No. 50-013137, Amendment No. 3
Attachment A
Statement of Services & Project Schedule
In accordance with the provisions of Article 1,Merrick agrees to perform the services specifically
described below.
I. Character and Extent of Services
Weld County(County)hereby engages Merrick&Company(Merrick)to provide necessary mapping services for
the County's digital mapping project. Merrick agrees to supply the following work and services under the conditions
set forth in this agreement:
A. Merrick and its subcontractors, shall provide all necessary work,material,supplies,transportation,plan,
labor,and management as may be required,to accomplish aerial photography digital orthophotography for
this project.
B. Supplies and services to be furnished under this contract will be divided into several sub-tasks. In summary,
the services include:
Photogrammetric Mapping
1. Establish new photo control/checkpoints.
2. Placement of aerial targets on existing and new photo control/checkpoints.
3. AGPS surveying for additional photo control points.
4. Black and white(B&W)aerial photography products.
5. Fully Digital Analytical Aerotriangulation(FDAAT).
6. Autocorrelate Digital Elevation model(DEM).
7. B&W digital orthophotography(1'pixel resolution).
8. MrSID compressed imagery.
C. Area of the Project-The limits of the project contain approximately nine hundred eighty-six(986) square
miles requiring one-foot(1')pixel resolution digital orthophotography formatted to the PLSS used in the
original 1998 and subsequent projects. See Figure 1 for the locations of said project limits.
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Contract No. 50-013137, Amendment No. 3
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Contract No. 50-013137, Amendment No. 3
II. General Mapping and Administration Considerations
A. Deliveries-All costs of deliveries shall be borne by the Merrick project team. Each delivery shall be
addressed to: Ms. Judi Boeck,GIS Coordinator, Weld County GIS, 1400 North 17th Avenue, Greeley, CO
80631. A letter and/or transmittal form,in duplicate, listing the materials being transmitted, and being
properly numbered,dated,and signed, shall accompany each delivery. Delivery of all County-supplied
source materials shall be made at the completion of this contract.
B. Mr.Doug Jacoby will be the Merrick technical manager for this project. Mr. Brian Raber will be the
Merrick contract manager for this project. Mr. Doug Jacoby will be the primary contact at Merrick for all
County correspondence. Ms. Judi Boeck will be the County's primary contact.
C. In the event the scope requires clarification the hierarchy of documents is as follows:
1. Amendment No. 3
2. Miscellaneous e-mail communications/documentation post Amendment No. 2 and prior to
executing Amendment No. 3
3. Amendment No. 2
4. Miscellaneous e-mail communications/documentation post Amendment No. 1 and prior to
executing Amendment No.2
5. Amendment No. 1
6. Miscellaneous e-mail communications/documentation post Contract No. 50-013137 and prior to
executing Amendment No. 1
7. Contract Document(Contract No. 50-013137)
8. Merrick's Technical Proposal
9. County's RFP
10. County Addenda to RFP
The hierarchy applies only when there is a conflict between two(2)or more of the above-mentioned
documents.
D. Product Acceptance-All deliveries submitted by Merrick will be checked by the County. The County team
shall notify Merrick if there are any delays in the review period.
All reviews will be performed on a basis of work correctness and compliance with this contract and the
technical scope of work. Merrick shall work closely with the County to develop quality control
parameters/procedures for County staff. At a minimum,the data will comply with the following acceptance
criteria:
1. 95%feature attribute correctness.
2. 95%features completeness.
3. American Society for Photogrammetry and Remote Sensing(ASPRS)Map Standards for positional
accuracy of the planimetric and topographic databases.
4. Federal Geodetic Control Committee(FGCC)and County/Merrick survey standards.
5. American Society of Photogrammetry and Remote Sensing aerial photography standards.
Within a thirty(30)calendar day timeframe the County team will categorize each delivery as follows:
1. ACCEPTED,that is,meeting specifications with no more than minor and/or isolated exceptions.
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Contract No. 50-013137, Amendment No. 3
Accepted data will conform to the minimum standards(95%) for feature attribute correctness and
completeness. Accepted data is considered final,with no re-work by Merrick.
2. ACCEPTED WITH REWORK,that is,essentially the delivery conforms to specifications,but having
a significant number of isolated exceptions. Client shall accept the delivery pending re-editing and
corrections re-submitted to the Client. At no cost to Client,the Merrick project team shall correct and
resubmit the delivery to Client within thirty(30)days. Deliverables falling within 90%to 95%will be
considered under this category. The Merrick project team will complete corrections to obtain the
minimum standard.
3. REJECTED,that is,the delivery fails to meet the minimum requirements and requires major
improvements to comply with the pre-defined standards. At no cost to the Client team,the Merrick
project team shall correct and re-submit the delivery to Client within fifteen(15)working days.
Deliveries considered in this category are where data is under the 90%level. The Merrick project team
will complete corrections to obtain the minimum standard.
HI. Photogrammetric Technical Provisions
Any technical provision not clearly defined in this document may be referenced back to Attachment A("Statement
of Services and Project Schedule")of the original Agreement for Professional Services. The same or similar
methods will be used in the production of digital orthophotography that were previously used during the 1998,2001
and 2003 projects.
Ground Control Checkpoints
1. Merrick will perform all the ground surveying services.
2. Merrick will establish approximately thirty-five(35)control points(checkpoints) and aerial targets (panels)
throughout the project area. Twenty-four(24) of these 35 points exist and will be recovered,paneled and
verified to ensure network currency. The remaining eleven(11)points will be new.
3. Merrick proposes to target and survey all 11 new ground control points. The intent of these checkpoints is
for the support of this project only, and permanent monumentation is not being proposed. All new
monuments will be temporary(i.e.,PK nail,chiseled"X", or rebar).
4. The aforementioned Figure 1 illustrates the proposed control/checkpoint configuration.
5. These checkpoints will validate the accuracy requirements of the project as well as ensure meeting 1"=200'
scale National Map Accuracy Standards(NMAS) for all deliverable products.
6. Global Positioning System(GPS)techniques will be used to establish the new checkpoint locations. Static,
Rapid Static, and Kinematic GPS techniques shall be incorporated for the points required to complete the
mapping.
7. The horizontal accuracy shall be Second Order, Class II, GPS. The vertical accuracy will meet Third Order
specifications.
8. All horizontal control will be initially referenced to the Colorado State Plane Coordinate System(SPCS),
North Zone (0501),North American Datum of 1983, adjusted 1992 (NAD83/92). Final coordinates will be
provided in U.S. Survey Feet. The project vertical control datum will be based on the North American
Vertical Datum of 1988 (NAVD 88).
9. Merrick will generate the "Control Report," which documents the results of the GPS survey. This report will
include a brief narrative of all aspects of the GPS data collection process.
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Contract No. 50-013137, Amendment No. 3
Control Paneling
1. Prior to the aerial photography mission, Merrick will panel the photo control points so they will be visible on
the aerial photography. Merrick will coordinate the targeting and aerial photography tasks to ensure that the
targeting is complete before beginning the photography mission.
2. When possible,Merrick will use white paint to mark the location of each control point. White vinyl material
(3-ply thick)will be utilized for all those points that cannot be painted.
3. The shape of each panel will be either a "Y"or"X". The length of each panel leg will be twelve-feet(12') in
length and twenty-four inches(24")wide.
4. All vinyl targets will be inspected before the acquisition of photography to validate proper positioning and
condition.
5. All vinyl panel material will be removed upon completion and acceptance of the aerial photography.
Acquire New Aerial Photography
1. Black and white aerial photography will be acquired to meet the accuracy requirements of the digital
orthophotography.
2. Merrick will utilize Aerial Surveys International,LLC(ASI) of Watkins, CO to perform the photography
mission. The camera utilized by ASI for this project will incorporate forward motion compensation(FMC).
Additionally, ASI's aircraft is equipped with GPS navigation and an on-board receiver to accomplish the
camera positioning for the aerotriangulation.
3. The aerial photography will conform to industry standards established by the American Society of
Photogrammetry and Remote Sensing(ASPRS).
4. The following characteristics apply for the aerial photography Merrick is responsible for capturing:
Negative Scale: 1" = 1,320' (1:15,840)
Mapping Scale: 1"=200'(1:2,400)
Flying Altitude: 7,920'AMT
Forward Lap: 60%
Side Lap: 30%
Area per model: 907.20 acres
Number of Exposures: 963
Mapping Flight Lines: 23
Mapping Flight Line Miles: 846.0
Mapping Flight Line Direction: North—South
Mapping Photography Format: Stereo-model centered
5. Once the film is processed, inspected and approved, each exposure shall be clearly labeled at the edge of the
negative. The labeling shall include: date of photography, scale of photography,project name, flight line
number and exposure number.
Airborne GPS Photo-Control/Post-Processing
Merrick will use Airborne GPS (AGPS) in order to control the aerial photography.The following summarizes
Merrick's AGPS procedures:
1. The results from the kinematic data collection and/or data processing shall be simple coordinate values for
each common epoch of data recorded by both the GPS receiver on the aircraft and base receivers stationed on
the ground.
2. The photos shall be represented only by an exact time corresponding to the time that the GPS receiver
recorded the electronic pulse from the camera when the photo was taken. These times shall be labeled with
photo identifiers by referring to the trajectory plots and the pilot flight reports so that the line numbers match
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Contract No. 50-013137, Amendment No. 3
those used by the pilot and thus, ensuring easy cross referencing. At the same time test exposures and events
caused by blanks shall be removed from the event list.
3. Coordinates and elevations will be generated for the perspective center for each photograph that will be used
in the fully digital analytical aerotriangulation (FDAAT)process.
4. The final coordinate values will be based on the Colorado State Plane Coordinate System(SPCS),North
Zone (0501),North American Datum of 1983, adjusted 1992 (NAD83/92), U.S. Survey Foot Units. Final
elevation values will be relative to the North American Vertical Datum of 1988 (NAVD88).
Aerial Photography Scanning
1. The original aerial photography negatives will be converted to raster images using the Zeiss SCAI film
scanner currently in place at Merrick
2. The input scan will vary based on the photo scale and desired output pixel resolution. The following table
illustrates the relationship between scale of photography, input scan size, and output pixel resolution:
Photo Scale Input Scan Input Pixel Final Pixel
1"=1,200' 14/um 0.66' 1'
3. When scanning the negatives, gray scale histograms or look-up tables (LUT's) are customized to establish the
optimum"bell shaped curve". This will assure the digital ortho imagery will have a well-balanced array of
grayscale values that range from 0 to 255.
Fully Digital Analytical Aerotriangulation (FDAAT)
The aerotriangulation process physically and mathematically ties individual exposures and associates the entire
photo set with the project's horizontal and vertical datums. Sophisticated software corrects inherent systematic
errors such as earth curvature, atmospheric refraction, film distortion, camera lens distortion and aircraft(flight)
inconsistencies. The result of the final FDAAT solution is exterior orientations for each camera station; x,y,z
location at the photo center and tip,tilt and swing of the camera at the instant the photo was captured. The
exterior orientations are used to set models during the stereo-compilation phase.
Merrick will perform the soft pugging, fiducial and plate mensuration on analytical, softcopy stereo-plotters in a
digital environment. Digital aerotriangulation eliminates the traditional manual labor(pugging and mensuration)
and many of the classical errors associated with traditional aerotriangulation. The end result is substantial cost
savings for the project through automated processes.
Merrick has three (3) workstations available for softcopy aerotriangulation. Leica/Helava's ORIMA
(Orientation Management) software will be used to perform all phases of the triangulation process. ORIMA
works with Airborne GPS data in a wide variety of formats. This allows Merrick to work with most aerial
photography companies that have different aerial cameras, GPS systems and orientation capabilities.
Merrick uses a systematic and time-tested procedure for completing fully digital aerotriangulation:
FDAAT Preparation
1. The input data for FDAAT includes the AGPS data, ground control, scanned imagery, camera calibration
data.
2. Prior to this step, the aerial negatives will have been scanned at 141um. This will ensure adequate resolution
for feature definition for the aerial triangulation point correlation and digital ortho imagery.
3. Plots of the Airborne GPS data are generated to correlate each photo exposure with an AGPS event.
4. During the preparation phase, Merrick compensates for systematic error such as "drift"by creating a profile
for each project. The drift parameters that impact the accuracy of the FDAAT adjustment include unresolved
ambiguities, datum errors and the antenna offset. This profile allows the automatic comparison between the
AGPS observations and FDAAT calculations of the photo-centers.
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Contract No. 50-013137, Amendment No. 3
5. Additional project support files are generated. A batch program is executed to correlate each strip of imagery
with the USGS Camera Calibration Report. Image files are minified to increase the efficiency of the
triangulation adjustment. Additional project-wide parameters(calibrated fiducial coordinates, ellipsoid,
antenna offset, strip Kappa, AGPS/ground control weightings, etc.) are input to a separate file.
6. The interior orientation for each image is recorded by measuring the fiducial marks on every exposure. This
is automatically accomplished in a batch process. Fiducial measurements are compared to the calibrated
coordinates from the Camera Calibration Report and an RMS is calculated for each exposure. The RMS
results are reviewed by the aerotriangulation technician to check for compliance with a set standard of less
than ten microns (<10/vn). Anomalies are investigated and resolved before proceeding to the next step.
7. After these preparation steps are verified and approved, the digital mensuration process will begin.
FDAAT Mensuration
1. The ORIMA APM (Automatic Tie Point Measurement)module completes digital mensuration using auto-
correlation techniques. Pattern recognition algorithms locate the exact same position on two adjoining digital
images. The subsequent softcopy adjustment will use coordinates of the correlated points (x,y in the image
system)to compute the actual ground coordinate values in the desired coordinate system.
2. The ORIMA software uses a pyramid structure for the imagery(minified files previously generated) of
approximately five levels with the final level possessing the finest resolution. This pyramid structure is used
to initially correlate coarser resolution images, and then refines the matched features in subsequent,higher
resolution pyramid levels.
3. Point matching is initially completed for each strip of photography. A minimum of three(3)points is
matched at classical Grueber locations in the tri-lap of each consecutive set of three images. The software
automatically flags potential matching errors, or the technician can review an ASCII file of the results. Any
matching errors (residuals)are also displayed graphically to the technician for review and resolution. The
software provides the flexibility to re-measure points interactively, in the event that points cannot be
automatically matched in a particular area.
4. The technician measures all ground control points for each strip interactively. Control points that fall in the
image area of adjoining strips are automatically tied via the control point designation number in the
adjustment phase.
5. Once the technician has reviewed and accepted the strip-wise matching, tie points are auto-correlated
between strips. The same QC procedures used to identify and resolve strip mismatches are completed for tie
points.
6. The final auto-correlated coordinates results are used as input to the FDAAT bundle adjustment.
FDAAT Bundle Adjustment
A block adjustment is performed using Leica/Helava's ORIMA CAP-A software to calculate coordinates for tie
points and determine precise exterior orientation parameters for each exposure. The exterior orientation
parameters will be used for stereo model orientation and as input to the digital orthophoto process.
Final QC and Aero-Triangulation Report
1. Throughout the FDAAT process Merrick is inspecting(approving and rejecting) the data before proceeding
with the next step of the process. Thus,by the time the bundle adjustment is executed, only potential errors
in the input control are remaining. The technician thoroughly reviews the residual and RMS results of the
AGPS, ground control and terrain(matched)points to ensure that the final results will support the accuracy
requirements of the project.
2. Merrick strongly encourages the use of checkpoints as an independent verification of the final bundle
adjustment.
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Contract No. 50-013137, Amendment No. 3
3. A comprehensive report detailing the results of the FDAAT task will be submitted to the County. The report
will include, at a minimum,the following information:
• A brief narrative of the aerotriangulation process.
• Root Mean Square(RMS)error and residuals of the ground control points.
• A discussion of any control misfits and corrective actions taken to resolve misfits.
• A statement of accuracy.
• A digital file of exposure locations with flight and exposure number annotated.
4. The final FDAAT coordinates will be consistent with the horizontal and vertical datums for the Weld County
project(i.e., Colorado SPCS,North Zone [0501],NAD 83/92,NAVD 88, U.S. Survey Feet).
5. The final report will be inspected and signed by Merrick's Project Manager, a Certified Photogrammetrist and
FDAAT Technician.
Autocorrelation of the Digital Elevation Model(DEM)
Merrick will compile a new DEM in support of the ortho rectification task. This will ensure consistency in
regards to currency, accuracy and seamlessness
Autocorrelation is a cost-effective and accurate method for collecting grid points in areas that are generally void
of buildings and dense trees. This project is well suited for utilizing automated DEM extraction techniques.
Merrick utilizes the Leica/Helava Systems Automatic Terrain Extraction (ATE) to collect grid points directly
from a series of stereo-pair images that have been controlled using the previously described FDAAT procedure.
In order to successfully generate a DEM, the following sequence of steps will be followed:
1. FDAAT completed and approved.
2. Terrain characteristics are analyzed to determine grid spacing.
3. If necessary, supplemental breaklines are collected interactively in 3-dimension (3-D)on the softcopy stereo-
plotters. Keep in mind that these supplemental breaklines are only captured as necessary since the DEM is
only supporting the ortho rectification (i.e.,a breakline required in a DTM may not necessarily be required
for a DEM).
4. Automatic Terrain Extraction (ATE) is executed to generate grid point postings. In the grid development
process, the software determines elevations by measuring x-shifts (x parallax) in the rectified images. It
begins with a small scale minification level image and sparse post spacing and increases the post density for
each minification level until the 1:1 minification level is reached. The height and accuracy of every elevation
post is stored in the DEM file. Tolerances may be set to ensure that posts are not generated within a certain
distance of pre-collected breaklines or exclusion boundaries. This ensures that correlated data will not
conflict with interactively compiled data. Additionally, the ATE algorithm will also eliminate, to a certain
degree, elevations on"undesired"height objects(buildings, square feet, trees, etc.).
5. The DEM collected to this point(breaklines and grid points) is draped on the 3-D images. Mass points are
then added at maxima and minima locations (peaks, depressions and saddles) if necessary.
6. One of the most important aspects in the process of DEM autocorrelation is the post-editing process. With
today's technology,post-editing is necessary to eliminate correlation errors and undesired height postings,
regardless of the brand of software used. Leica/Helava's Interactive Terrain Edit(ITE) module is highly
sophisticated and provides superior performance over other similar software packages. It allows interactive
editing with the following tool sets:
• Area Editor—changes all post elevations within a defined polygon and is used for changing elevation
postings in large areas; typically areas with constant elevations
• Post Editor—allows post-by-post review and edit and is used for detail editing
• Geomorphic Editor—forces the DTM to conform to breakline that are input after ATE is executed
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Contract No. 50-013137, Amendment No. 3
7. Once the DEM has been interactively and automatically derived and fully edited, "rough"or raw contours
will be generated. As an additional quality control step,Merrick will drape these contours on the 3-D
imagery to visually ensure that the contours are"on the ground." Remember that these contours will not
meet any vertical accuracy standards, but will ensure that the DEM supports accurate ortho rectification. The
ITE module also contains a Quality Statistics function that compares the DEM against control points.
Dieita[Orthophoto Production
The algorithms used to rectify imagery are static within the industry. Regardless of whether individual vendors
use off-the-shelf or customized software and all inputs being equal, the positional accuracy characteristics of the
final orthos will be essentially the same. Therefore,our focus is on image quality,production efficiencies, and
customer support.
The following is an overview of the process by which Merrick creates digital orthophoto images. There are five
(5)main steps involved in creating a digital ortho. These include the following:
1. Integration of the autocorrelated Digital Elevation Model (DEM)
2. Negative rasterization (scanning)
3. Fully differential orthometric rectification
4. Radiometric correction and image mosaicking
5. Data quality inspection and delivery
Secondary processes may include:
• Resampling to multiple resolutions
• File compression
• Integrating the imagery into Merrick's custom display and plotting extensions
Merrick uses Leica/Helava's latest release(4.3.4)of digital ortho processing software and high-end Dell
workstations. Each step of the production process has internal validation measures, which must be approved
before proceeding to the next step.
The following section outlines our procedures for generating the ortho imagery.
Input Validation and Setup
1. Image quality begins at the aerial photography stage. Merrick works with our aerial vendor to select the
appropriate film type for the project. The aerial negatives are thoroughly reviewed by our Digital Imaging
Discipline Lead for clarity, contrast, shadow detail, sunspots, and scratches
2. The project area is sub-divided into workable blocks for efficient processing(up to 50 stereo-models per
block). DEM data is merged for a given block and the elevation data is graphically displayed relative to the
project boundary to ensure that all areas will be correctly rectified.
3. Ultimately, orthophotos are as accurate as the rectification surface on which they are based. Rigorous quality
assurance procedures provide confidence that the DEM and consequently the orthophoto meet or exceed
specifications. Therefore, the DEM is evaluated using various isometric views check for any"spikes." The
technician also validates that the DEM blocks overlap to ensure that there are no data gaps between blocks.
4. A Triangulated Irregular Network(TIN) is generated from the DEM.
5. Project parameters(photo scale, camera calibration data, output resolution, etc.)are input to a project file for
access by the Leica/Helava software.
6. Interior orientations (fiducial measurements)are imported from stereo-compilation department to obviate the
need for re-measurement and maintain consistency between the compiled data and final ortho imagery.
7. A reduced resolution data set is created by minifying(re-sampling)the scanned imagery. The reduced
resolution data set will be subsequently used for the initial rectification.
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Image Rectification and Processing
1. Establishing or defining the ground surface and scanned negative relationship via digital orientation are the
next steps in the process. Digital images are geo-referenced to the DEM surface through an interior(from the
camera calibration report)and exterior orientation (from the FDAAT)of the scanned image. These
orientations relate the scanned image to the camera and subsequently the camera to the ground.
2. Leica/Helava's module MO is executed to simultaneously rectify and mosaic an entire block of imagery.
This process is completed on the minified data set as an initial rectification to expedite processing. Merrick
will use a Cubic Convolution re-sampling method, with the ability to edge-enhance or smooth an image as
needed to arrive at the best geometric and radiometric output possible in the commercial market today.
3. Seam lines are automatically generated by the software and displayed to the technician. Tone and contrast
are adjusted automatically between input images during this process, with the images then feathered across a
buffer zone to eliminate seam lines within the project area.
4. The ortho technician reviews the locations of the seam lines and manually modifies them to avoid height
objects and to place them in monotone areas(through open field, along road centerlines, etc.). The
technician also reviews the image characteristics and modifies a block-wide histogram as necessary to adjust
the overall tonal balance.
5. A second and final rectification is completed on the full resolution data set using the modified parameters
and edited seam lines from the initial adjustment. Tonal balancing on a block basis is again reviewed to
ensure consistent imagery. Overall image quality is reviewed to ensure that the imagery is of consistent tone
and contrast across the project area, and to specifically look for any breaks or processing failures within the
image. Any such breaks will be cause for rejection and recreation of the affected sheets after determining the
nature of the problem.
6. The block of imagery is cut to individual delivery tiles. For this project, the tiling characteristics include:
Ortho Scale Tile Size Number of Tiles Pixel Resolution File Size
1"=200' —5,280' x 5,280' 986 1' —28mb
(PLSS section)
7. A visual inspection of each tile is completed for aesthetics (dust, lint, scratches, smears,building and bridge
lean, etc.)
8. Bridges are corrected by rectifying them at"zero"elevation. The rectified feature is referenced and
transferred to the final image file.
Image Characteristics
Merrick recognizes that the quality of orthophoto imagery can be subjective. Imagery that may look good to one
person may not to someone else. For this reason, we work closely with our clients during the start-up and
prototype processes to develop imagery that is suitable for all users. Our philosophy is that we are working as a
team with our clients to achieve the desired results for their intended applications.
The following outlines potential orthophoto quality issues that may arise on any given project and Merrick's
solutions to these issues.
Image Clarity
The clarity of the image can be significantly affected by atmospheric haze and dust. Thus, aerial photography
will be taken in accordance with ASPRS Standards for Aerial Photography whereby the "photography shall not
be secured when the ground is obscured by haze, snow, smoke, dust, flood waters, or environmental factors that
may obscure ground detail." The aerial photography is thoroughly reviewed for compliance with this standard.
Brightness/Contrast
Brightness and contrast can be controlled during the film processing, scanning, and orthophoto processing
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phases. The best way to achieve the proper brightness and contrast is through proper film selection and film
processing. Although these factors can be controlled somewhat during the scanning and ortho processing phases,
the extent to which they can be controlled is primarily dependent on the quality of film processing. Merrick
completes a histogram analysis of the imagery prior to scanning to analyze and adjust the dynamic range of gray
scale values for brightness and contrast. Brightness and contrast can also be further adjusted on a project-wide
basis during the mosaicking process.
We recognize that acceptable brightness and contrast of the ortho imagery is subjective and varies from client to
client. In an effort to determine the optimum image quality parameters at the onset of the project, Merrick will:
■ Review the contrast and brightness of a sample set of imagery during the prototype review meeting
Shadows
The extent to which shadows impact the imagery is a direct result of the time of year and time of day that the
photography was flown. Longer shadows will give an overall appearance of darker imagery in heavily shadowed
areas even though a histogram analysis may show that the imagery is similar. Regardless of the film type used or
the time of year/day flown,you should be able to identify at least some, and preferably all, detail in shadow
areas. To ensure the highest possible visibility of detail in shadows, the aerial vendor must properly expose the
film and process the film according to manufacturer's specifications.
Scratches
• Scratches can be introduced at various stages of the process. Scratching can occur when the film passes across
the platen in the camera, as the film is being passed through a film processor, as the film is being used to generate
contact prints/diapositives, as the film is being scanned or even as the film is being rolled across a light table for
review. It is difficult to completely eliminate scratches.
To minimize the impact of scratching, Merrick works exclusively with aerial vendors that use the latest in camera
and film processing technology. These vendors also recognize the importance of proper handling and storage of
the original negatives. 'Whenever film is being reviewed on a light table,the technician wears white gloves and
the table is thoroughly cleaned.
Scratches are "paint-brushed"out during the orthophoto image QC check. The heaviest concentration is placed
on scratches that fall on planimetric features, although any scratch that is unsightly is fixed. The extent to which
scratches are fixed is a subject discussed at the kickoff and prototype review meetings.
Artifacts
Artifacts(lint, dust, etc.) can be introduced any time the film is being rolled out for any purpose. Although
vendors and their subcontractors usually take great care to avoid scratches and artifacts, it is nearly impossible to
eliminate them altogether. Artifacts that are unsightly or that fall on critical features are "paint-brushed"out
during the orthophoto image QC check.
Mosaicking
Mosaicking is completed as a standard process to minimize the effect of inherent tonal variations from photo to
photo. Our ortho technicians will review and modify seam lines so that they are placed in areas of consistent
tonal balance and between buildings or bridges. A dynamic range adjustment is completed across the entire
block of images to provide a tonally balanced product. The mosiacking parameters can be carried from block to
block to ensure the entire project area has consistent tonal qualities.
Radial Displacement(Buildings)
Due to the radial properties of the aerial camera,buildings will "lean"outward from the center of each exposure.
The extent to which a building leans is a function of the height of the building and the distance from the nadir of
the photo. This can be very detrimental to ortho imagery since the leaning buildings will obscure otherwise
visible features.
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Contract No. 50-013137, Amendment No. 3
Radial Displacement (Bridges and Overpasses)
In the case of bridges and multi-level overpasses,the orientation of the bridge in relation to the principle point of
the photograph plays a large part in the output appearance of that bridge. If the bridge is oriented close to the
photo center, very little modification, if any,may be required for that bridge. If the bridge is located to the edge
of the photo center, a marked degree of modification can occur to that structure, such as warping,ribboning,
melting, etc. Merrick will make every attempt to rectify bridges and overpasses using portions of the imagery
that are closest to the center of each exposure, thus minimizing the lean of these features.
Positional Accuracy
The best way to internally validate that the final ortho products meet the required accuracy standard is by
measuring control points on the final ortho photos and comparing the values with the survey control coordinates.
Planimetry is overlaid with the image data as well to check specifically for correct fit,placement, and
completeness of the data prior to final formatting and delivery.
Final Digital Ortho Formatting
1. Final image quality and geometric fit is reviewed before translation to the client-specific file format. Once
translation has occurred, the translated images are displayed to ensure no errors have occurred in translation.
The images are then written to the specified media for delivery to the client, and are backed up with all
related project data to assure data recovery for future operations.
2. For this project, we anticipate that all imagery will be output as Continuous Tone,TIFF Class G format files
with a World File.
3. Note that the PLSS section formatted tiles along the exterior limits of the Weld County corporate limit will
be extended an additional one hundred fifty feet (150')to ensure boundary coverage. This is similar to the
1998, 2001, and 2003 projects. The County will provide the PLSS tile grid inclusive of this. This will affect
seventy-four(74) of the 986 PLSS tiles.
Acceptance Criteria
The County understands that the quality of ortho imagery is subjective to each user and quantifying the
acceptability of ortho imagery, in specific terms, is not a goal of this project. Due to inherent anomalies in aerial
photography, the County accepts that there will be minor variations in brightness, contrast and color tone in the
ortho imagery throughout the project area. The following will be used as a guideline for acceptance of the digital
orthophotography. These anomalies must be apparent when viewing at the intended mapping scale(i.e., 1"=200'
[1:2,400] scale).
Scratches and Artifacts
Accepted—Minor scratches and artifacts only. Scratches and artifacts in areas of"insignificance"such
as water,trees, fields, etc. Scratches and artifacts,regardless of location, do not detract from usability or
overall aesthetics of imagery.
Accepted with Rework—Significant scratches and artifacts throughout tile. Scratches and artifacts on
numerous planimetric detail such as buildings,roads, etc. Scratches and artifacts detract from usability
or overall aesthetics of imagery.
Contrast
Accepted—Contrast is the same or very similar to agreed to prototype.
Accepted with Rework-Contrast is significantly different than agreed to prototype.
Radiometry/Seamlines
Accepted-Only minor variations between tiles or flight strips when viewed in conjunction with
surrounding tiles or across project/delivery area. Seamlines between individual source photos are nearly
or completely invisible. Obvious attempts have been made to "feather"seamlines and they have been
placed primarily in monotone or inconspicuous areas.
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Accepted with Rework- Significant variations are apparent between tiles or flight strips when viewed
in conjunction with surrounding tiles or across project/delivery area. Obvious seam lines exist between
source photos with no apparent attempt to correct. Seam lines have been placed through buildings when
other routes could have been used.
Clarity
Accepted -Image is clear and primarily free of blurred areas within the limitations of mosaicking and the
source aerial photography. Pixel resolution is correct as per specifications. All image pixels exist.
Accepted with Rework—Image is not clear or has numerous areas blurring that can be attributed to
factors outside the source aerial photography. Pixel resolution is greater than defined by specifications.
Image pixels have dropped out.
Warping/Stretching
Accepted—Imagery is free of warped or stretched areas.
Accepted with Rework—Image has warped or stretched area that cannot be attributed to extremely
steep terrain.
Edge Matching
Accepted—Ortho tiles edge match within the tolerances of accuracy requirements.
Accepted with Rework—Ortho tiles do not edge match within accuracy specifications.
Positional Accuracy
Accepted—Ortho imagery matches planimetric data within the tolerance of accuracy specifications. {+/-
calculations on control and/or check points} are within accuracy specifications.
Accepted with Rework—Ortho imagery does not match planimetric data within the tolerance of
accuracy specifications. {+/-calculations on control and/or check points} are not within accuracy
specifications.
MrSID Image Compression
Following image acceptance, Merrick will compress the data using MrSID compression software developed by
LizardTech. Merrick is a business partner with Lizard Tech and has the in-house capabilities to provide this
service. Merrick would work closely with Client to establish the most appropriate compression ratio(s). Typical
compression of panchromatic (black and white)imagery is 20-25:1 and offers a much more manageable dataset
conducive to LAN and/or Internet transfers and applications.
IV. Deliverable Products
The following outlines the deliverable products produced by Merrick. Merrick understands that all of the
products listed below are the property of Weld County.
Ground Control Surveying
1. ASCII Coordinate listing of all checkpoints established(existing and new).
2. Simple control /GPS report including narrative, field notes, sketches, etc.
Aerial Photography Products
1. One(1) set of 1"=1,320' scale black and white (B&W) film negatives.
2. One(1) set of flight line/control diagrams for each scale of aerial photography(copies of USGS quad
maps).
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Contract No. 50-013137, Amendment No. 3
Fully Digital Analytical Aerotriangulation (FDAAT)Products
1. FDAAT report and computation results for said aerial photography(hard and soft copy).
2. ASCII text file of the existing ground control/checkpoints and AGPS photocenters used in the FAAT task.
3. USGS Camera Calibration Report.
Digital Orthophoto Products
I. One(1) set of CD-ROM's containing nine hundred eighty-six (986) PLSS formatted tiles of 1"=200' scale/
one-foot(1')pixel resolution B&W digital orthophotography in TIFF format.
2. MrSID compressed imagery of the aforementioned 1' pixel resolution B&W digital orthophotography.
V. Project Schedule
The following outlines the production schedule for the aforementioned Statement of Services specified for Weld
County:
Mapping Task Start Finish
1. Ground Control/Aerial Targets 2/28/05 3/11/05
2. 1"=1,320 Scale Black and White(B&W)Aerial Photography w/AGPS 3/14/05 4/15/05
3. B&W Film Negative Scanning 4/18/05 5/13/05
• 4. Fully Digital Analytical Aerotriangulation (FDAAT) 5/16/05 6/24/05
5. Prototype Project 6/27/05 7/22/05
6. Prototype Project Review 7/25/05 8/12/05
7. Prototype Project Review Meeting at Merrick 8/12/05*
8. Ortho-only Digital Elevation Model (DEM)Development 8/15/05 9/9/05
9. B&W Digital Orthophotography Rectification/Processing (I' pixels) 9/12/05 12/2/05
10. B&W Digital Orthophotography Delivery 10/7/05
11. B&W Digital Orthophotography Delivery 11/4/05
12. B&W Digital Orthophotography Delivery 12/2/05
13. County review and Acceptance 10/10/05 12/30/05
14. MrSID Imagery Compression and Delivery 1/2/06 1/13/06
* Tentative Date (if deemed necessary)
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Attachment B
Schedule of Payment
The following outlines the compensation due Merrick&Company for the work described in Attachment A:
Task Description Contract Amount
1. Project Initiation/Planning $ 2,175.00
2. 1"=1,320' Scale B&W Aerial Photography w/AGPS $ 24,750.00
3. Recon Control/Aerial Targets/AGPS Support $ 16,605.00
4. Fully Digital Analytical Aerotriangulation (FDAAT) $ 22,450.00
5. Digital Elevation Model (DEM) Compilation $ 23,610.00
6. Film Negative Scanning $ 12,182.00
7. B&W Digital Orthophotography Rectification $ 24,748.00
8. MrSID Compression $ 2,076.00
9. Project Management $ 5,385.00
10. Project Controls/Administration $ 1,860.00
TOTAL $ 135,841.00*
* Equates to$137.77 per square mile.
Merrick will invoice Weld County on a monthly basis based on a percent complete of each of the aforementioned
tasks.
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Contract No. 50-013137, Amendment No. 3
Attachment C
Additional County Responsibilities
The following lists the information and responsibilities required of the County.
Project Start-up Information
1. Identification of project boundaries for the project area.
2. Provide the corrected/adjusted PLSS coverage(s) for the project area.
Countywide Project Production
1. Provide Merrick with timely review, feedback and acceptance of project deliverables.
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Attachment D
Documents and Deliverables Owned by Weld County
Merrick understands that all of the products listed below are the property of Weld County.
Data Provided to Merrick
1. Corrected/adjusted PLSS coverage.
2. Any and all source documents provided
Ground Control Surveying
1. ASCII Coordinate listing of all checkpoints established (existing and new).
2. Simple control/GPS report including narrative, field notes, sketches, etc.
Aerial Photography Products
1. One (I) set of 1"=1,320' scale black and white (B&W) film negatives.
2. One (1) set of flight line/control diagrams for each scale of aerial photography(copies of USGS quad
maps).
Fully Digital Analytical Aerotriangulation (FDAAT)Products
1. FDAAT report and computation results for said aerial photography(hard and soft copy).
2. ASCII text file of the existing ground control/checkpoints and AGPS photocenters used in the FDAAT task.
3. USGS Camera Calibration Report.
Digital Orthophoto Products
1. One(1) set of CD-ROM's containing nine hundred eighty-six(986)PLSS formatted tiles of 1"=200' scale/
one-foot(1')pixel resolution B&W digital orthophotography in TIFF format.
2. MrSID compressed imagery of the aforementioned 1' pixel resolution B&W digital orthophotography.
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