2000 Digital Orthophotos, Twin Cities Metropolitan Area, resampled to 1-meter pixel size and compressed

This page last updated: 04/09/2007
Metadata created using Minnesota Geographic Metadata Guidelines


Metadata Summary

Originator Land Management Information Center (for EPPLViewer 2001), based on Metropolitan Council data.
Abstract This data set is derived from the Metropolitan Council's 2000 Digital Orthopohotos for the Twin Cities Metropolitan Area, but with modifications by the Land Management Information Center which include resampling to a 1-meter pixel size and compression of the data.

The original Metropolitan Council data set contains 267 black and white digital orthophoto quarter-quadrangles (DOQs), 3.75' x 3.75', covering the 7 county Twin Cities (Minneapolis and St. Paul) Metropolitan Area in Minnesota. The orthophotos are in UTM, Zone 15, NAD83 projection. Each image is approximately 115 Mb, with a .6 meter image pixel, and available in TIFF format. These orthophotos were produced using the USGS DOQ specifications except for the file format and the scan resolution (pixel size is .6m rather than 1 meter). The original imagery was collected at 20,000 ft. and centered on USGS quarter-quads.

The resampled, compressed 1-meter DOQs for the year 2000 were created by LMIC for use with the EPPLViewer 2001 tool within the metropolitan area. The resampling and compression reduces the size of the data set from 78 CDs to 2 CDs.
Browse Graphic none available
Time Period of Content Date 05/2000
Currentness Reference The dates of the original aerial photography were May 1, 2000 (West Half of the metro) and May 2, 2000 (East Half of the metro).
Access Constraints For use with EPPLViewer 2001 only. Use of the parent DOQ year 2000 Metropolitan Council data set is subject to license agreement with the Metropolitan Council.
Use Constraints For use with EPPLViewer 2001 only.

Generally, our experience suggests that the integrity of the photos begins to degrade at 1:2,500 scale. Usually 1:1,750 is the maximum one should zoom into an image. Actual results will vary depending on the quality of the individual photo and the physical landscape.
Distributor Organization Minnesota Land Management Information Center (LMIC)
Ordering Instructions Contact Distributor.
Online Linkage none available

Full Metadata

2000 Digital Orthophotos, Twin Cities Metropolitan Area, resampled to 1-meter pixel size and compressed

Go to Section:
1. Identification Information
2. Data Quality Information
3. Spatial Data Organization Information
4. Spatial Reference Information
5. Entity and Attribute Information
6. Distribution Information
7. Metadata Reference Information

 
Section 1 Identification Information   Top of page
Originator Land Management Information Center (for EPPLViewer 2001), based on Metropolitan Council data.
Title 2000 Digital Orthophotos, Twin Cities Metropolitan Area, resampled to 1-meter pixel size and compressed
Abstract This data set is derived from the Metropolitan Council's 2000 Digital Orthopohotos for the Twin Cities Metropolitan Area, but with modifications by the Land Management Information Center which include resampling to a 1-meter pixel size and compression of the data.

The original Metropolitan Council data set contains 267 black and white digital orthophoto quarter-quadrangles (DOQs), 3.75' x 3.75', covering the 7 county Twin Cities (Minneapolis and St. Paul) Metropolitan Area in Minnesota. The orthophotos are in UTM, Zone 15, NAD83 projection. Each image is approximately 115 Mb, with a .6 meter image pixel, and available in TIFF format. These orthophotos were produced using the USGS DOQ specifications except for the file format and the scan resolution (pixel size is .6m rather than 1 meter). The original imagery was collected at 20,000 ft. and centered on USGS quarter-quads.

The resampled, compressed 1-meter DOQs for the year 2000 were created by LMIC for use with the EPPLViewer 2001 tool within the metropolitan area. The resampling and compression reduces the size of the data set from 78 CDs to 2 CDs.
Purpose To provide Minnesota government agencies, planners, and other decision-makers with 2000 aerial photography that can be efficiently distributed and viewed.
Time Period of Content Date 05/2000
Currentness Reference The dates of the original aerial photography were May 1, 2000 (West Half of the metro) and May 2, 2000 (East Half of the metro).
Progress Complete
Maintenance and Update Frequency Unknown. The Metropolitan Council is required to collect generalized land use data at the same time as the Census. The Met. Council plans to acquire aerial imagery again by 2005. LMIC will create a resampled version of these updates when available.
Spatial Extent of Data Twin Cities 7 County Metropolitan Area. This includes the counties of Anoka, Carver, Dakota, Hennepin, Ramsey, Scott and Washington in Minnesota.
Bounding Coordinates -94.06
-92.69
45.44
44.44
Place Keywords Twin Cities, Anoka County, Carver County, Dakota County, Hennepin County, Ramsey County, Scott County, Washington County
Theme Keywords imageryBaseMapsEarthCover, orthophotography, ortho, orthophotos, DOQ, DOQQ, imagery, images, digital ortho, aerial photography, aerial photos, digital aerial photography
Theme Keyword Thesaurus ISO 19115 Topic Category
Access Constraints For use with EPPLViewer 2001 only. Use of the parent DOQ year 2000 Metropolitan Council data set is subject to license agreement with the Metropolitan Council.
Use Constraints For use with EPPLViewer 2001 only.

Generally, our experience suggests that the integrity of the photos begins to degrade at 1:2,500 scale. Usually 1:1,750 is the maximum one should zoom into an image. Actual results will vary depending on the quality of the individual photo and the physical landscape.
Contact Person Information Ken Pekarek, EPPL7 Coordinator
Minnesota Land Management Information Center (LMIC)
300 Centennial Building; 658 Cedar Street
St. Paul, Minnesota 55155
Phone: 651-201-2499
FAX: 651-296-3698
E-mail: clearing.house@state.mn.us
Browse Graphic none available
Browse Graphic File Description
Associated Data Sets 2000 Metropolitan Council Digital Orthophotos, see:
http://www.datafinder.org/metadata/orthos2000.htm
1997 Metropolitan Council Digital Orthophotos, see:
http://www.datafinder.org/metadata/orthos1997.htm
1991 United States Geological Survey DOQs - statewide, see:
http://www.lmic.state.mn.us/chouse/metadata/doq.html
1991 United States Geological Survey DOQ's resampled to 10 Meters,see:
http://www.lmic.state.mn.us/chouse/metadata/doq10m.html

 
Section 2 Data Quality Information Top of full metadata Top of page
Attribute Accuracy
Logical Consistency
Completeness Entire seven county metro area is covered. There is a limited overlap beyond county borders.
Horizontal Positional Accuracy From metadata for original Metropolitan Council DOQ 2000 data set: National Map Accuracy Standards @ 1:12,000 scale, 90% of well-defined points fall within 33.3 ft
Vertical Positional Accuracy Not applicable
Lineage 1. PARENT DATA SET: Creation of 2000 Digital Orthophotos, Twin Cities Metropolitan Area (.6 meter resolution) (Metropolitan Council):

Orthophotos were developed under contract with MARKHURD Inc.

The contractor acquired new, vertical black and white aerial photography at a photo scale of 1=3333' (1:40,000 scale or at an altitude of 20,000 ft), following the USGS NAPP specifications. There were 22 flight lines, 612 exposures, 590 exposures used for aerotriangulation (AT), 60% forward overlap and 30% side lap, flown in a north/south orientation covering the project area.

The contractor acquired and processed airborne GPS data for the center of each photo. This was used as input in to the AT solution.

The contractor scanned each film diapositive at a setting of 14 microns to yield a 2' ground resolution pixel size (.6 meter). TIFF images were exported for use in the softcopy workstation for the AT and ortho processing.

A Fully Analytical Aerotriangulation (AT) of the aerial photography was developed to be used in the orthorectification process. This increases the density of the ground control network, verifies the accuracy of the GPS survey check points, and provides independent comparison of the existing ground control points.

The Council provided the USGS 30 Meter DEM to the contractor in ArcInfo GRID and in ASCII format, in UTM, NAD 83, horizontal units in meters, vertical units (Z-units) in feet, tiled by USGS quadrangle. The DEM files are used in the orthorectification process.

The contractor used a softcopy process to create the final digital orthophotos. Digital Orthophoto Quarter-Quads were developed following the USGS standards for digital orthophotos (DOQs) with the exception of pixel resolution (.6 meter), file format (TIFF with world files). USGS header (.hdr) file were not included as a deliverable.

These orthophotos were produced using the USGS DOQ specifications except for the file format and the scan resolution (pixel size is .6m rather than 1 meter). The original imagery was collected at 20,000 ft. and centered on USGS quarter-quads.

2. DERIVED DATA SET: Creation of derived 1-meter, compressed Metro DOQs from the Metro 2000 data set described in part 1 of 'Lineage' (Land Management Information Center, EPPL7 Team, 2001):

The original files from the Metro 2000 .6-meter pixel data set were purchased by LMIC from the Metropolitan Council Data Center as a 78-CD data set. The original CDs contained scanned TIFF files that did not have geo-coordinates assigned to each pixel. The associated World file did make the data set available in ArcView GIS for viewing only, but not available to EPPLViewer or EPIC2000.

Using a new import function in the 32-bit Beta version of EPPL7, each of the quarter-quadrangle TIFF files were converted into EPP format, making them fully Geo-registered files capable of being used in a GIS system. The quarter-quads were then aligned to the NW quarter-quadrangle, mosaiced together and rescaled to create a 1-meter x 1-meter cell quarter-quadrangle file. The 1-meter cell size was selected for ease of comparison between the 2000 photos and the USGS county 1-meter 1990's DOQs available on CD. The files were then compressed into JPEG format similar to the USGS 1990's DOQ county CDs. The same naming conventions were used for each 1/4 quad image.

All the quads were resampled from the original .6-meter cell resolution to a 1-meter cell size and a JPG compression was applied at a quality factor of 35%. All quarter-quad files are named the same as the data files on the USGS county DOQ CDs. Refer to the USGS for naming conventions for each quad. Generally, the name is longitude, latitude,(1-64) (NE NW SW SE) = H for header, or C for compressed JPG data file. All data is in UTM NAD83, Zone 15 extended. ArcView users can access the JPG files the same as with the USGS county DOQ CDs.
Source Scale Denominator 40000
 
Section 3 Spatial Data Organization Information Top of full metadata Top of page
Native Data Set Environment JPG
Geographic Reference for Tabular Data
Spatial Object Type Raster
Vendor Specific Object Types
Tiling Scheme 3.75 minute quadrangle sheets (USGS 7.5 minute ''quarter quads'')
 
Section 4 Spatial Reference Information Top of full metadata Top of page
Horizontal Coordinate Scheme UTM
Ellipsoid GRS80
Horizontal Datum NAD83
Horizontal Units Meters
Distance Resolution
Altitude Datum NAVD88
Altitude Units Meters
Cell Width 1.0
Cell Height 1.0
UTM Zone Number 15
 
Section 5 Entity and Attribute Information Top of full metadata Top of page
Entity and Attribute Overview
Entity and Attribute Detailed Citation
 
Section 6 Distribution Information Top of full metadata Top of page
Publisher Minnesota Land Management Information Center (LMIC)
Publication Date 07/15/2001
Contact Person Information Ken Pekarek
EPPL7 Coordinator
Minnesota Land Management Information Center (LMIC)
300 Centennial Building, 658 Cedar Street
St. Paul, Minnesota 55155
Phone: 651-201-2499
FAX: 651-296-3698
E-mail: clearing.house@state.mn.us
Distributor's Data Set Identifier doqeppl
Distribution Liability State of Minnesota Disclaimer
NOTICE

The Geographic Information System (GIS) Data to which this notice is attached are made available pursuant to the Minnesota Government Data Practices Act (Minnesota Statutes Chapter 13). THE GIS DATA ARE PROVIDED TO YOU AS IS AND WITHOUT ANY WARRANTY AS TO THEIR PERFORMANCE, MERCHANTABILITY, OR FITNESS FOR ANY PARTICULAR PURPOSE. The GIS data were developed by the Land Management Information Center for its own internal purposes. LMIC does not represent or warrant that the GIS Data or data documentation are error-free, complete, current, or accurate. You are responsible for any consequences resulting from your use of the GIS data or your reliance on the GIS Data. You should consult the data documentation for this particular GIS Data to determine the limitations of the GIS Data and the precision with which the GIS data may depict distance, direction, location, or other geographic features.
Transfer Format Name .jpg
Transfer Format Version Number
Transfer Size Approximately 3 Mb per quarter-quadrangle; entire dataset is approximately 1 GB.
Ordering Instructions Contact Distributor.
Online Linkage none available
 
Section 7 Metadata Reference Information Top of full metadata Top of page
Metadata Date 04/09/2007
Contact Person Information Susanne Maeder,
Minnesota Land Management Information Center (LMIC)
300 Centennial Building; 658 /Cedar Street
St. Paul, Minnesota 55155
Phone: 651-201-2488
FAX: 651-296-3698
E-mail: clearing.house@state.mn.us
Metadata Standard Name Minnesota Geographic Metadata Guidelines
Metadata Standard Version 1.2
Metadata Standard Online Linkage http://www.lmic.state.mn.us/gc/stds/metadata.htm


This page last updated: 04/09/2007