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CRCOG Orthoimagery
FGDC, ESRI Metadata
DescriptionSpatialData StructureData QualityData SourceData DistributionMetadata
+ Resource Description
Information used to reference the data.
Title: CRCOG Orthoimagery
Originators: Shawn Benham, The Sanborn Map Company
Publication date: 20170117
Data type: Final
Other citation details:
remote-sensing image
A characterization of the data, including its intended use and limitations.
This data is a collection of orthorectified aerial imagery. The orthorectified imagery was delivered in uncompressed tiled 8-bit format (4band RGBCIR). Project wide and county mosaics (MrSID Gen3 and Gen4) were also delivered at 20:1 ratios. The data was produced at the request of the Capitol Region Council of Governments of Connecticut by The Sanborn Map Company of Colorado Springs. This orthorectified imagery has a pixel resolution of 0.25'. The data was flown from March12 to April 16 of 2016 using an UltraCam Eagle camera. This data is within the Connecticut State Plane Coordinate System, Datum of NAD83 (2011) and is in US Survey Feet.
Rectified orthoimagery is for public use. An orthoimage is useful as a layer of any geographic information system (GIS). It can function as a cartographic base for displaying, generating, and modifying associated digital planimetric data. Other applications include environmental impact assessments, disaster management, emergency evacuation planning, flood analysis, soil erosion assessment, facility management, ground-water and watershed analysis, right of way and road alignment, transportation network inventory and analysis, preliminary design studies, vegetation classification detection of physical features or attributes not possible at ground level, and a myriad of additional applications.
Dataset credit:
Capitol Region Council of Governments of Connecticut
Point Of Contact
Contact information for the individual or organization that is knowledgeable about the data.
Organization: Capitol Region Council of Governments of Connecticut
Person: Erik D. Snowden
Position: IT/GIS Coordinator
Phone: 860-522-2217 x 217
Fax: 860-724-1274
Email: esnowden@crcog.org
Address type: mailing and physical address
241 Main St
City: Hartford
State or Province: CT
Postal code: 06106
Country: USA
Data Type
How the data are represented, formatted and maintained by the data producing organization.
Data type: Final
Native dataset environment: Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS
Time Period of Data
Time period(s) for which the data corresponds to the currentness reference.
Beginning date: 20160312
Ending date: 20160416
Currentness reference:
Regions defined by the Capitol Region Council of Governments of Connecticut.
The state of and maintenance information for the data.
Data status: Complete
Update frequency: None planned
Key Words
Words or phrases that summarize certain aspects of the data.
Keywords: Imagery, Orthophotography, Photography, Ortho, Orthoimagery
Keyword thesaurus: None
Keywords: imageryBaseMapsEarthCover
Keyword thesaurus: ISO 19115 Topic Categories
Keywords: Connecticut
Keyword thesaurus: None
Data Access Constraints
Restrictions and legal prerequisites for accessing or using the data after access is granted.
Access constraints:
None.  This data is in the public domain.
Use constraints:
None.  Users can copy, modify, distribute and perform work, even for commercial purposes, without requesting permission.
+ Spatial Reference Information
Horizontal Coordinate System
Reference system from which linear or angular quantities are measured and assigned to the position that a point occupies.
Projected coordinate system:
Name: StatePlane Connecticut Feet
Map units: survey feet
Geographic coordinate system:
Name: GCS North American 1983
Coordinate System Details
Map projection
Standard parallel: 41.2
Standard parallel: 41.8
Longitude of central meridian: -72.75
Latitude of projection origin: 40.8
False easting: 999999.9
False northing: 499999.9
Map projection name: Lambert Conformal Conic
Planar Coordinate Information
Planar coordinate encoding method: coordinate pair
Coordinate representation:
Abscissa resolution: 0.25 Feet
Ordinate resolution: 0.25 Feet
Planar distance units: survey feet
Geodetic model
Horizontal datum name: D North American 1983 (2011)
Ellipsoid name: GRS 1980
Semi-major axis: 6378137.0
Denominator of flattening ratio: 298.257222101
Spatial Domain
The geographic areal domain of the data that describes the western, eastern, northern, and southern geographic limits of data coverage.
Bounding Coordinates
In Unprojected coordinates (geographic)
GCS North American 1983
West-73.753 (longitude)
East-71.774 (longitude)
North42.061 (latitude)
South40.973 (latitude)
+ Data Structure and Attribute Information
Summary of the information content of the data, including other references to complete descriptions of entity types, attributes, and attribute values for the data.
Entity and attribute overview:
Color orthophotos are comprised of pixels. Each pixel is assigned a value of 0 to 255. That number will refer to a color look-up table which contains red, green and blue (RGB) values, each from 0 to 255, for that pixel within the image.
Entity and attribute detailed citation:
Direct spatial reference method: Raster
Raster Information
Type and number of raster spatial objects in the data.
Raster format: GeoTIFF
Raster object type: Pixel
Number of raster bands: 4
Raster properties
Raster origin: Upper Left
Compression type: None
Raster display type: Pixel Codes
Cell information
Bits per cell: 8
Background nodata value: 255
Cell Size:
X units: 0.25
Y units: 0.25
+ Data Quality and Accuracy Information
Information about the fidelity of relationships, data quality and accuracy tests, omissions, selection criteria, generalization, and definitions used to derive the data.
Logical consistency report:
The digital imagery for each acquisition sortie is differentially rectified to produce orthophotography at a resolution of 3in.  Once the imagery has passed quality control review, final radiometric adjustments are performed to create a uniform overall appearance.  The process is overseen by a ASPRS Certified Photogrammetrist (CP). The CP overseeing production at Sanborn is Doug Zehr.
Completeness report:
The ortho image tiles are checked for missing pixels, gaps, overlaps and other anomalies generally associated with digital orthophoto products. Any discrepancies in the ortho tiles are resolved through the use of proprietary and industry editing tools. Once the images are copied to the deliverable media they are further checked for naming, image completeness, and ability to be loaded in ArcMap.
Cloud cover: 0
Attribute Accuracy
Accuracy of the identification of data entities, features and assignment of attribute values.
Attribute accuracy report:
Attribute accuracy assessment:
Accuracy values
Digital orthoimagery does not contain inherent attribution.
Positional Accuracy
Accuracy of the positional aspects of the data.
Horizontal accuracy report:
Horizontal accuracy is based on ground control and digital elevation model data provided by Sanborn Map Company that was used in the production of the digital orthoimagery.
Horizontal positional accuracy assessment:
Accuracy values
0.5-foot RMSE
Specification requires that data meet a 0.50' RMSE requirement.  Points were surveyed and compared to locations within the orthophotos and meet this specification.
Vertical accuracy report:
Vertical positional accuracy assessment:
Accuracy values
Orthoimagery does not have inherent vertical accuracy.
+ Data Source and Process Information
Data Sources
Information about the source data used to construct or derive the data.
Data source information
Title: Aerial Photography
Originators: The Sanborn Mapping Company, Inc.
Publication date: 2016
Data type: remote-sensing image
Media: Aerial Images
Source contribution:
The aerial imagery was captured with an UltraCam Eagle digital camera. The Eagle is a full frame digital camera system.  The aerial images are used to AT the project and the production of orthophotos.
Beginning date: 20160312
Ending date: 20160416
Currentness reference:
ground condition
Process Steps
Information about events, parameters, tolerances and techniques applied to construct or derive the data.
Process step information
Process Step 1
Process description:
New digital, color aerial imagery of the site is acquired using Microsoft UltraCAM Eagle aerial camera systems. Airborne GPS/IMU data is recorded along with the imagery.
Organization: The Sanborn Map Company, Inc.
Person: Shawn Benham
Position: Program Manager
Phone: (719)502-1296
Phone: 719-502-1296
Email: sbenham@sanborn.com
Hours of service: 8 - 5 Eastern Time
Address type: mailing and physical address
1935 Jamboree Dr #100
City: Colorado Springs
State or Province: CO
Postal code: 80920
Country: USA
Process date: 201604
Process Step 2
Process description:
The digital aerial imagery was transferred from the UCEcamera to a Mass Storage Unit (MSU) and shipped to Sanborn's main facility in Colorado Springs.  Once downloaded, data is processed via Microsoft Ultramap software from the raw camera format to a 4-band unsharpened color image and a pan image. An application is executed that outputs the mid-exposure pulse for each image. At this point a POS file is processed photo files as input to the Aerial Triangulation process. Raw camera data files are archived on LTO3 tapes. The imagery is processed using UltraMap processing software to create a 4-band multispectural (RGBN) format. The images are archived (on LTO3 tapes) and removed from system when orthophotography production has been completed.
Process date: 201610
Process Step 3
Process description:
Softcopy (Digital) Aerotriangulation: This task involved the densification of ground control points, measurement of photo coordinates, computation and block adjustment to solve for exterior orientation parameters of individual photographs necessary for ortho-rectification. New ground control locations surveyed by the Sanborn map company; a combination of photo-identical points and targeted points were used.  The ground control points were measured in a fully digital environment using softcopy stereoplotters and tie point and passpoints automatically generated. Analytical aerotriangulation computations and adjustment were done using Inpho Match-AT software, which is capable of performing bundle block adjustments using a rigorous least squares analysis, and possesses error detection and removal facilities. Systematic error corrections for lens distortion, earth curvature, and atmospheric refraction.  State-of-the-art software with highly sophisticated error-detection routines was used to perform the computation and bundle block adjustment. Trained aerial triangulation specialist analyzed both numerical printouts and graphical error vector output display to detect gaps or holes in the block due to missing tie points, pass points or ground control.
Process date: 201609
Process Step 4
Process description:
The digital elevation model (DEM) data was provided by Sanborn, for the purpose of rectification of the imagery. LiDAR was used to create the DEM. The DEM is updated where needed to support accurate rectification of the orthoimagery.
Process date: 201609
Process Step 5
Process description:
Orthorectification: This task involved orthorectification of the raw digital raster images that were created from processing of Microsoft Ultracam Eagle digital camera data. A number of image processing techniques were used to maximize the quality of the deliverable images. Digital orthoimagery was created by draping the un-rectified raster images over their corresponding digital terrain models. All relief displacement was removed from the raw image files at ground level on a pixel-by-pixel basis using mathamatical pixel manipulation and seams, yielding a set of orthorectified digital photo images.   Mosaicking was performed to ensure a perfect edge match between all orthoimage tiles. Seam lines were generated automatically and manually manipulated where necessary to ensure that no image flaws result from seam lines passing through tall structures.  Seamline calculations bring in radiometric values of the pixels that are used first and then the terrain is brought into the equation.  The software uses the radiometric values to go around cars and buildings the best it can.  If the software detects a substantial change in the surface (like steep hills to cliffs), the software will try to compensate with another image, to avoid smearing  of the imagery.  If the seams would not compensate for the surface change, it would create a smear or the hillside would be more stretched than it should be.  There will be, on occasion, patches of seams hiding these terrain changes.   All orthoimagery  tiles were generated butt joints, no overlaps nor gaps. Radiometric adjustment was performed to balance and match color tones, brightness and contrast of the imagery over the whole project. Color orthoimagery were produced 8-bit per channel, resulting in 8-bit RGBN, .tif/.tfw format with a pixel size of 0.25ft. Ortho tiles were generated according to the pre-approved orthoimagery  tile layout.
Process date: 201611
Process Step 6
Process description:
Quality Control All orthophoto tiles were thoroughly inspected according to Sanborn QA/QC quality control procedures. Comprehensive visual inspection included looking for mosaicking, image smearing and color balancing across the entire project. The process is overseen by a ASPRS Certified Photogrammetrist.  The CP Overseeing production at Sanborn is Doug Zehr.
Process date: 201611
Process Step 7
Process description:
Dataset moved.
Process date: 201612
Process Step 8
Process description:
Metadata updated/imported
Process date: 201701
+ Data Distribution Information
Description of the data known by the party from whom the data may be obtained, liability of party distributing data, and technical capabilities required to use the data.
Resource description:
Downloadable Data
Distribution liability:
Distribution Point of Contact
Contact information for the individual or organization distributing the data.
Organization: Capitol Region Council of Governments of Connecticut
Person: Erik D. Snowden
Position: IT/GIS Coordinator
Phone: 860-522-2217
Fax: 860-724-1274
Email: esnowden@crcog.org
Address type: mailing address
241 Main st
City: Hartford
State or Province: CT
Postal code: 06106
Standard Order Process
Common ways in which data may be obtained.
Digital form:
Format name: Digital
Transfer size: .135
Digital transfer option:
Offline option:
Offline media: FTP or Digital disk
Recording format: FTP or Copy
Fees: n/a
+ Metadata Reference
Metadata Date
Dates associated with creating, updating and reviewing the metadata.
Last updated: 20170117
Metadata Point of Contact
Contact information for the individual or organization responsible for the metadata information.
Organization: The Sanborn Mapping Co., Inc.
Person: Shawn Benham
Position: Project Manager
Phone: (719)502-1296
Email: sbenham@sanborn.com
Address type: mailing
1935 Jamboree Drive, Suite 100
City: Colorado Springs
State or Province: CO
Postal code: 80920-5358
Metadata Access Constraints
Restrictions and legal prerequisites for accessing or using the data after access is granted.
Access constraints:
None.  This data is in the public domain.
Use constraints:
None.  Users can copy, modify, distribute and perform work, even for commercial purposes, all without requesting permission.
Metadata Standards
Description of the metadata standard used to document the data and reference to any additional extended profiles to the standard used by the metadata producer.
Standard name: FGDC Content Standard for Digital Geospatial Metadata
Standard version: FGDC-STD-001-1998
Time convention: local time
FGDC Plus Metadata Stylesheet
Stylesheet: FGDC Plus Stylesheet
File name: FGDC Plus.xsl
Version: 2.3
Description: This metadata is displayed using the FGDC Plus Stylesheet, which is an XSL template that can be used with ArcGIS software to display metadata. It displays metadata elements defined in the Content Standard for Digital Geospatial Metadata (CSDGM) - aka FGDC Standard, the ESRI Profile of CSDGM, the Biological Data Profile of CSDGM, and the Shoreline Data Profile of CSDGM. CSDGM is the US Federal Metadata standard. The Federal Geographic Data Committee originally adopted the CSDGM in 1994 and revised it in 1998. According to Executive Order 12096 all Federal agencies are ordered to use this standard to document geospatial data created as of January, 1995. The standard is often referred to as the FGDC Metadata Standard and has been implemented beyond the federal level with State and local governments adopting the metadata standard as well. The Biological Data Profile broadens the application of the CSDGM so that it is more easily applied to biological data that are not explicitly geographic (laboratory results, field notes, specimen collections, research reports) but can be associated with a geographic location. Includes taxonomical vocabulary. The Shoreline Data Profile addresses variability in the definition and mapping of shorelines by providing a standardized set of terms and data elements required to support metadata for shoreline and coastal data sets. The FGDC Plus Stylesheet includes the Dublin Core Metadata Element Set. It supports W3C DOM compatible browsers such as IE7, IE6, Netscape 7, and Mozilla Firefox. It is in the public domain and may be freely used, modified, and redistributed. It is provided "AS-IS" without warranty or technical support.
Instructions: On the top of the page, click on the title of the dataset to toggle opening and closing of all metadata content sections or click section links listed horizontally below the title to open individual sections. Click on a section name (e.g. Description) to open and close section content. Within a section, click on a item name (Status, Key Words, etc.) to open and close individual content items. By default, the Citation information within the Description section is always open for display.
Download: FGDC Plus Stylesheet is available from the ArcScripts downloads at www.esri.com.