USGS High Resolution Orthoimagery, Ramsey County, Minnesota, Spring 2006

This page last updated: 01/09/2013
Metadata created using Minnesota Geographic Metadata Guidelines

Go to Section:
1. Overview
2. Data Quality
3. Data Organization
4. Coordinate System
5. Attributes
6. Distribution - Get Data
7. Metadata Reference

Section 1 Overview
Originator U.S. Geological Survey and Martinez Corporation
Title USGS High Resolution Orthoimagery, Ramsey County, Minnesota, Spring 2006
Abstract This dataset consists of 0.15-meter pixel resolution (approximately 6-inch), natural color orthoimages covering Ramsey County, Minnesota.

An orthoimage is remotely sensed image data in which displacement of features in the image caused by terrain relief and sensor orientation have been mathematically removed. Orthoimagery combines the image characteristics of a photograph with the geometric qualities of a map.

[Note: this metadata record was reformatted at the Minnesota Geospatial Information Office from the record provided by USGS - several of the fields were changed to reflect MnGeo's seamless WMS data delivery]
Purpose This data can serve a variety of purposes, from general planning to field reference for spatial analysis to a tool for revision of vector information at ground level. It can also serve as a reference layer for GIS. These data have been created as a result of the need for having geospatial data immediately available and easily accessible in order to provide geographic reference for Federal, State, and local emergency responders, as well as for homeland security efforts. Orthoimages also serve a variety of purposes, from interim maps to field references for earth science investigations and analysis. These data can be used to provide reference information for Web browsers and for map applications at a scale of 1:100,000 or smaller. Larger scale orthoimagery such as digital orthophoto quadrangles will be more accurate, but often at the expense of timely updates.
Time Period of Content Date 04/09/2006
Currentness Reference ground condition
Progress Complete
Maintenance and Update Frequency Irregular
Spatial Extent of Data Ramsey County, Minnesota
Bounding Coordinates -93.23
Place Keywords Ramsey County, MN, Minnesota
Theme Keywords imageryBaseMapsEarthCover, orthophoto, air photo, aerial photo, aerial photography, image map
Theme Keyword Thesaurus ISO 19115 Category
Access Constraints Any downloading and use of these data signifies a user's agreement to comprehension and compliance of the USGS Standard Disclaimer. Insure all portions of metadata are read and clearly understood before using these data in order to protect both user and USGS interests.
Use Constraints There is no guarantee of warranty concerning the accuracy of the data. Users should be aware that temporal changes may have occurred since this data set was collected and that some parts of this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its limitations. Acknowledgement of the originating agencies would be appreciated in products derived from these data. Any user who modifies the data is obligated to describe the types of modifications they perform. User specifically agrees not to misrepresent the data, nor to imply that changes made were approved or endorsed by the U.S. Geological Survey. Please refer to for the USGS disclaimer.
Contact Person Information Steve Martinez, Vice President
Martinez Corporation
2910 Waters Road
Eagan, MN  55121
Phone: 651-686-8424
Fax: 651-686-8389
Browse Graphic None available
Associated Data Sets For information on other air photos available for Minnesota, see

Section 2 Data Quality
Attribute Accuracy Radiometry is verified by visual inspection of the digital orthophoto. Slight systematic radiometric differences may exist between adjacent orthoimage files; these are due primarily to differences in source image capture dates and sun angles along flight lines. These differences can be observed in an image's general lightness or darkness when it is compared to adjacent orthoimage file coverages. Tonal balancing may be performed over a group of images during the mosaicking process which may serve to lighten or darken adjacent images for better color tone matching.
Logical Consistency Logical consistency is implicit in the raster image data structure. Source imagery is cloud free.
Completeness No report
Horizontal Positional Accuracy Using the National Standard for Spatial Data Accuracy, the data set tested 0.672 Feet horizontal accuracy at 95% confidence level. This data exceeds the ASPRS Class 1 standards.
Vertical Positional Accuracy Not applicable as it pertains to a two-dimensional raster image.
Lineage Martinez Corporation obtained color aerial photography covering Ramsey County and portions of Anoka, Dakota, Hennepin, and Washington counties. Great Lakes Aerial Survey (GLAS) was contracted to obtain the aerial photography on April 9, 2006. Martinez Corp. used elevation models provided by each of the counties mentioned above to create digital ortho images.

GLAS acquired aerial photography utilizing a gyro stabilized aerial camera equipped with forward motion compensation (Wild RC30, Wild Universal Aviogon /4-8, SN: 13373, CFL: 153.465 mm). This project was flown at an altitude of 5000 feet above ground level (AGL). Spatial-specific information not available.

Aerial Photography was scanned at a resolution of 14 microns (1814 DPI) using a Vexcel VX4000 Image Scanning System. The scanned imagery was aero-triangulated and geo-referenced to the Ramsey County Coordinate System (nonHARN). The imagery was tone balanced so that the color of the imagery was accurate and consistent throughout the entire study area, seamlines were manually selected. Orthophotos were created using elevation models obtained from Ramsey, Anoka, Washington and Dakota Counties. The elevation models were reviewed and edited to represent the terrain conditions of the 2006 aerial photography prior to the ortho-rectification process. The orthophotos were reviewed for geometric and radiometric accuracy as well as tone consistency. Bridges and overpasses were corrected to the appropriate horizontal position and artifacts were removed using Photoshop methods.

Data_Set_Credit: Martinez Corporation and the Ramsey County Surveyor's Office


MnGeo converted the imagery from Ramsey County coordinates in feet to UTM Zone 15 coordinates in meters. MnGeo staff then read the imagery directly into a database that serves the images over the web via a WMS server in JPG format.

Section 3 Spatial Data Organization (not used in this metadata)

Section 4 Coordinate System
Horizontal Coordinate Scheme Universal Transverse Mercator
UTM Zone Number 15
Horizontal Datum NAD83
Horizontal Units meters
Cell Width 0.15
Cell Height 0.15

Section 5 Attributes
Overview Wild RC30 Calibrated Focal Length: 153.465mm. Orthophoto Pixel Size = 0.5
Detailed Citation
Table Detail:

Section 6 Distribution
Publisher USGS and MnGeo
Publication Date 2007
Contact Person Information Nancy Rader, GIS Data Coordinator
Minnesota Geospatial Information Office
658 Cedar Street
St. Paul, MN  55155
Phone: 651-201-2489
Fax: 651-296-3698
Distributor's Data Set Identifier Ramsey County high resolution DOQs 2006
Distribution Liability 1. USGS Disclaimer:

Although these data have been processed successfully on a computer system at the USGS, no warranty expressed or implied is made by the USGS regarding the use of the data on any other system, nor does the act of distribution constitute any such warranty. Data may have been compiled from various outside sources. Spatial information may not meet National Map Accuracy Standards. This information may be updated without notification. The USGS shall not be liable for any activity involving these data, installation, fitness of the data for a particular purpose, its use, or analyses results.

2. MnGeo disclaimer:
Ordering Instructions 1. MnGeo's Geospatial Image Server

The imagery is available to view via WMS (Web Mapping Service) from MnGeo's Geospatial Image Server. Click on 'Online Linkage' field below to see a webpage that provides the url to connect to the Geospatial Image Server as well as information about how to use WMS services.

2. NorthStar Mapper

View and download imagery from MnGeo's NorthStar Mapper online interactive map at:

After you click on "Start Mapping", find these photos as the "Ramsey Co. Air Photos 2006" layer under "Air Photos and Basemaps"
For help using NorthStar Mapper, see:
Online Linkage I AGREE to the notice in "Distribution Liability" above. Clicking to agree will either begin the download process or link to download information. See "Ordering Instructions" above for details.

Section 7 Metadata Reference
Metadata Date 01/09/2013
Contact Person Information Nancy Rader, GIS Data Coordinator
Minnesota Geospatial Information Office
658 Cedar Street
St. Paul, MN  55155
Phone: 651-201-2489
Fax: 651-296-3698
Metadata Standard Name Minnesota Geographic Metadata Guidelines
Metadata Standard Version 1.2
Metadata Standard Online Linkage

This page last updated: 01/09/2013
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