| snippet:
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This dataset was created for historical analysis at scales of 1 inch = 400 feet or smaller. |
| summary:
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This dataset was created for historical analysis at scales of 1 inch = 400 feet or smaller. |
| accessInformation:
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Illinois State Geological Survey and the Geographic Information Systems (GIS) and Mapping Division of the Lake County Department of Information and Technology |
| thumbnail:
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thumbnail/thumbnail.png |
| typeKeywords:
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["Data","Service","Image Service","ArcGIS Server"] |
| description:
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This is a single, seamless countywide image.
The aerial photos used to create the mosaic on this CD were taken on various dates in July and August 1939. They were scanned in 2001, and georeferenced in 2002. This data should NOT be used at a scale larger than 1 inch = 400 feet. Due to the lack of sufficient camera calibration information, errors will increase towards the margin of each underlying photo, although this effect has been minimized by cropping individual photos to make this mosaic. Since these photos were scanned from paper prints, local distortions (from the media stretching and/or shrinking) may be present as well as pen marks and fading.
In order for this information to fit on to the CD media it has been compressed with Lizardtech's MrSID software at a 1:5 target ratio.
The image is georeferenced to the Illinois State Plane, Eastern Zone, using the NAD83 horizontal datum.
Caution should be used in interpreting features in this photography with reference to current conditions. In particular, many roads and road intersections have been realigned in the more than 60 years since this photography was taken.
This historic aerial photography was captured in digital form as the result of a cooperative project between the Illinois State Geological Survey and the Geographic Information Systems (GIS) and Mapping Division of the Lake County Department of Information and Technology. It is part of a statewide program to preserve the oldest known extensive aerial photography for future generations.
The original photography was performed by the U.S. Department of Agriculture as part of a nation-wide program for use in agricultural assessment.
Since the original negatives became unstable and were destroyed by the National Archives in the 1980's, only paper prints remain. A set of paper prints representing the best available quality was assembled from the collections of several agencies. The scanning, georeferencing and mosaic processes are described in more detail on our website. |
| licenseInfo:
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| catalogPath:
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|
| title:
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Lake_IL_1939_webM |
| type:
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Image Service |
| url:
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http://clark.fm.pri:6080/arcgis/services/1939_aerials/Lake_IL_1939_webM/ImageServer |
| tags:
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["United States of America","State of Illinois","County of Lake","17","097","digital orthophoto","digital image map","aerial photograph","rectified photograph","rectified image","orthophoto","historical"] |
| culture:
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en-US |
| name:
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Lake_IL_1939_webM |
| guid:
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|
| spatialReference:
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WGS_1984_Web_Mercator_Auxiliary_Sphere |