Identification Information

Title MRCOG 2020 Digital Orthophotography Mosaic

Date 2021-03-05

Date Type Publication

Cited Responsible Party

Organization Name Bohannan Huston, Inc.

Role identify

Presentation Form raster digital data

Abstract This digital orthophotography dataset consists of tiled orthophotos covering approximately 3,607 square miles as part the MRCOG 2020 digital orthophotography project. The 16,033 tiles of orthophotography depict four-band color (Red, Green, Blue, and Infrared (RGBI)) digital aerial photographs acquired in the spring of 2020. The project tiling scheme of one-quarter square mile tiles is organized according to PLSS second division and City of Albuquerque grid scheme. Lens and terrain distortion have been removed through orthorectification and tonal differences between adjacent images have been minimized to form a color-balanced mosaic of the entire project area. Orthorectified imagery corrects for geometric distortion and creates an image-based map with features represented appropriately at ground level. Above-ground features such as buildings and bridges may show some distortion or lean due to elevation. Bridges and elevated roads have been checked for warping due to elevation modeling and corrected. Each orthorectified pixel is exactly 0.5 ft. square. This orthophoto product conforms to American Society for Photogrammetry and Remote Sensing (ASPRS) Class I Standards for 1"=100' horizontal mapping or current ASPRS Positional Accuracy Standards for Digital Geospatial Data for Standard Mapping product where Horizontal Accuracy at the 95% Confidence Level is less than or equal to 3 pixels. Project coordinate systems were established on the New Mexico State Plane North Central Zone HARN projection (EPSG:2903), with horizontal datum referenced to the North American Datum of 1983 (NAD83), and vertical datum to the North American Vertical Datum of 1988 with units of U.S. Survey Feet.

Purpose The purpose of this project is to support activities throughout the MRCOG MPO, including but not limited to Geographic Information Systems data maintenance, urban, community and regional planning; project and infrastructure planning; project reporting; floodplain mapping; stormwater management; vegetation analysis; change detection; and initial project reviews.

Data Set Credit Acknowledgement of the MRCOG and Bohannan Huston, Inc. would be appreciated for products derived from these data. Data is owned by the MRCOG.

Status Complete

Point of Contact

Individual Name

Organization Name Mid-Region Council of Governments (MRCOG)

Position Name Transportation Planner

Role Point of contact

Voice 505-247-1750

Facsimile

Address

Delivery Point 809 Copper Avenue NW
City Albuquerque
Administrative Area NM
Postal Code 87102
Country USA

Electronic Mail Address info@mrcog-nm.gov

Maintenance and Update Frequency As needed

Descriptive Keywords biota

Access Constraints Access to this data set is provided by the MRCOG.

Use Constraints Neither the Mid-Region Council of Governments (MRCOG), nor Bohannan Huston, Inc. (BHI) assumes liability for misuse of the data. Data should be used at the scale for which they were intended. No warranty, expressed, or implied, is made by MRCOG nor BHI regarding the utility of the data on any other system, nor shall the act of distribution constitute such warranty. THIS PUBLICATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. THE MRCOG SHALL NOT BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES RELATED TO THE USE OF THIS PUBLICATION, WHETHER OR NOT MRCOG IS ADVISED OF SUCH DAMAGE.

Language English

Topic Category

Extent

Geographic Bounding Box

West Bound -107.223801
East Bound -106.12346
North Bound 35.700282
South Bound 33.857082

Temporal Extent

Beginning Position 2020-03-19
Ending Position 2020-05-18

Data Quality Information

Attribute Accuracy Report

Report Radiometric qualities of the imagery have been inspected and color balancing processing applied to create near seamless imagery mosaics. Slight radiometric differences may exist between adjacent orthorectified photos. Radiometric differences may be attributable to changes in time and date of source image acquisition and sun angles differences along flight lines. To minimize these variations image flight acquisition adhered to ASPRS capture standards requiring at least a 30 degree sun angle above horizon for all flights. Tonal balancing was also performed during image mosaicking to adjust and optimize color matching between adjacent photos. Slight post process image sharpening was applied to the project imagery.

Quantitative Attribute Accuracy Assessment

Attribute Accuracy Value
Attribute Accuracy Explanation

Horizontal Positional Accuracy Report

Report Tested 0.52 ft. (RMSE) and 0.91 ft. horizontal accuracy (NSSDA 95% confidence) to well-defined primary aerial photography control.

Quantitative Horizontal Positional Accuracy Assessment

Horizontal Positional Accuracy Value
Horizontal Positional Accuracy Explanation

Logical Consistency Report Orthophoto tiles have been validated for image file/pixel size and inspected visually to ensure logical relationships between expected data elements.

Completeness Report Deliverable data tiles were inspected to ensure complete image data coverage. Data tiles may be comprised of multiple flight line data sources. Sources covering the orthophoto mosaic tiles are defined by flight line photo index information. The resulting digital orthophoto image (DOI) tile is a square. Pixelation (by project design) of areas may be present in locations of tiles/mosaics to purposely obscure imagery details.

Lineage

Source Information

Source Citation

Source Scale Denominator 600

Type of Source Media Portable Document Format

Source Time Period of Content

DateTime 2020-02-16
Source Currentness Reference ground condition

Source Citation Abbreviation BHI MRCOG Area Control Database

Source Contribution Geodetic control were established for the project to provide a primary control network for orthophotography mapping in the project coordinate system.

Source Information

Source Citation

Source Scale Denominator 600

Type of Source Media Hard drive

Source Time Period of Content

Beginning Position 2020-03-19
Ending Position 2020-05-21
Source Currentness Reference ground condition

Source Citation Abbreviation GC

Source Contribution Digital aerial imagery was collected at a nominal average orthometric height of 9,640 ft. above ground elevation using the Microsoft/Vexcel UltraCam Eagle (UCE) digital camera system. The UCE aerial imagery served the purpose of supporting the production of 6-inch ground sample distance (GSD) resolution digital orthoimagery.

Process Step

Process Description 1. Aerial Triangulation - Images were aerotriangulated to finalize their exterior orientation (EO). Intergraph ISAT and GeoMedia Professional were used to perform digital point matching/mensuration/block adjustments and quality control queries respectively. Final block adjustments were evaluated at sub-pixel accuracy.
Process Date 2020-06
Process Time
Process Contact

Process Step

Process Description 2. Orthorectification - Images were orthorectified to remove distortions caused by changes in the elevation of the terrain, camera orientation and lens distortion. The orthorectification process used a cubic convolution interpolation method and ground elevations created from the newly acquired digital imagery using photogrammetric point cloud processing (PPC). The PPC was then classified into bare earth for the creation of digital elevation models (DEM). Intergraph ImageStation OrthoPro® software used was for orthorectification. Delivery of 16-bit imagery was recieved and rectification was performed to an 8-bit pixel.
Process Date 2020-08
Process Time
Process Contact

Process Step

Process Description 3. Orthomosaic - Images were color balanced and color corrected individually to ensure color consistency between flight lines, time(s) of day, and date(s) of capture. Images were mosaicked into large aggregate tiles and automatic seamlines were used to combine the most nadir components of individual images. Aggregate tiles were again tonally balanced and color corrected with the entire project in view. A second global color adjustment was performed to minimize color changes across images. Project deliverable tiles were cut from the mosaic and formatted for delivery. Trimble OrthoVista® software was used to perform these steps.
Process Date 2020-09
Process Time
Process Contact

Process Step

Process Description 4. Orthophoto Quality Control (QC) and Delivery. Review processes were developed to comprehensively assess output orthophoto data tiles. This process was designed to identify any areas requiring additional effort to correct issues in automatic seam line placement and/or orthorectification (and bridge warping in particular). During this assessment, all orthophoto tiles were reviewed by analysts in GeoMedia Professional®. Issues requiring additional work were flagged using a “call” feature indicating the type of fix required. Next, specific rework sites were reprocessed with Adobe Photoshop® to remedy issues identified by call features. Final review of all fixed tiles was performed by an independent analyst to verify (Quality Assurance) that the call was corrected as required. Final QC data tiles were then processed for delivery to include production of compressed (GeoTIFF, MrSid, and ECW format) and uncompressed (GeoTIFF) tiles.
Process Date 2020-11
Process Time
Process Contact

Process Step

Process Description 5. Post QC Sensitive Area Pixelation. Area mosaics were reviewed by local agencies and Pueblos to identify areas where the orthoimagery may show sensitive features. Once reviewed directives were issued to pixelate the imagery within these areas. A record of pixelation coverage is documented in the shape file "MRCOG_2020_Blur_Areas.shp". These areas can include entire Pueblo boundaries and select locations within tiles throughout the project.
Process Date 2021-01
Process Time
Process Contact

MRCOG 2020 Digital Orthophotography Mosaic

Metadata from the RGIS Metadata Repository

Identification Information

Distribution Information

Spatial Reference Information

Data Quality Information

Metadata Reference Information