CUGIR dataset information
|USGS 7.5 Minute Topographic Maps (2000)|
|Theme||7.5 Minute Topographic Maps (2000)
Index of quad names established by the USGS and the NY Department of Transportation.
High-quality PDFs of all current and historical topographic maps for each quad are freely available from the USGS Store (follow the 'Map Locator & Downloader' link on that page).
If you prefer, select quad sheets by map rather than by name.
|Mapsheet||Blue Ridge 7.5-minute Quad|
|Provider||NYS Department of Environmental Conservation
For additional datasets available from NYSDEC, see the list of DEC datasets at the NYSGIS Clearinghouse.
|Format||GeoTIFF image .tif|
|Download||i48drg.tar.gz | Add to basket|
|Coordinate System||Universal Transverse Mercator | Meters | Zone 18|
|Datum||North American Datum of 1983|
|Publication date||July 28, 2000|
|Date added or updated||November 30, 2000|
This data set consists of images derived from scans of U.S.G.S. 7.5 minute quadrangle maps (Digital Raster Graphics). The images form a set of seamless tiles, 5,000 m on a side, from which the map collar information was removed. Images are GeoTIFF files in NAD83, UTM zone 18.
A DRG is useful as a source or background layer in a GIS, as a means to perform quality assurance on other digital products, and as a source for the collection and revision of DLG data.
1. Checking a sample of the DRGs produced by the U.S.G.S. indicated that the images were mis-registered by as much as 5 pixels (about 12 meters). Although the images were re-registered in an effort to reduce this error, perfect registration was not always possible. We found that some of the original images were scanned with distortion that could not be removed in the re-registration process. Thus, an unknown proportion of the images have errors which, when combined with any errors in the original maps, may exceed the limits of the National Map Accuracy Standards adhered to by the original maps. If a scanned image is to be used where accuracy at the 1:24,000 scale is needed, its registration accuracy should be verified. 2. The maps upon which the images are based used either metric contours in meters or English contours in feet. There is no easy way to determine which units are used for a particular image because the map collar information is not present. Users need to be aware of the need to use care in determining elevation units from these images. 3. For more background on Digital Raster Graphics, refer to the USGS. To identify codes used in the data go to <http://cugir.mannlib.cornell.edu/metadata/NY.DRG.Index.html>, the Index of New York State Digital Raster Graph (DRG) Quad Names established by the USGS and NY Department of Transportation (DOT).
|Topics||imagery & base maps|
|File size||5725 kilobytes|
|Use constraints||Acknowledgement of the USGS would be appreciated in products derived from these data.|
|Full metadata||HTML | XML | Text|
|Related||Mapsheets in other spatial series related to Blue Ridge 7.5-minute Quad|