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GIS Standards

NHNM routinely gives datasets to people and organizations making requests. The most convenient and accurate method to transfer data is through digital files.We use ESRI Arcview software to produce our data and we store the information in Arcview shapefile format. Currently, most of our data is stored as point locations, making it easy to export to a digital database file with X and Y coordinates for each point. However, in the future we will store increasing amounts of our data as polygons making it necessary for our clients to have GIS software to view the data.

Please note: A shapefile contains three separate files which must be kept together for the data to be functional in GIS. The extensions of the files are *.shp, *.shx and *.dbf.   For example, if the name of the file is "test" you will have test.shp, test.shx, and test.dbf files.

Options for viewing data

ARC/INFO Users
All NHNM geographic data is stored in Geographic, decimal degree, North American Datum 1927 (NAD27). We can provide reprojected data on request

Arcview Users
All NHNM geographic data is stored in Geographic, decimal degree, North American Datum 1927 (NAD27). We can provide reprojected data on request.

CAD Users
We can send our point data as a text file that will allow you to import the XY coordinates into your program. We include Latitude/ Longitude decimal degree. If you prefer another projection, such as Universal Transverse Mercator (UTM), we can reproject the data and include the projected coordinates as well in the text file.

Non GIS Users
ESRI has made available at no cost a product called Arc Explorer. Arc Explorer will allow you to view shape files and their databases. Using this program can give you more information than a paper map. Download it here.

Sending Data to the NHNM

Occasionally clients will send data to NHNM in a GIS. We can accept ESRI ArcInfo and ArcView formats. A projection file must accompany the data or a written explanation of the projection of the data must accompany the files. The projection, datum, and spheroid must be included. If the data are in Universal Transverse Mercator (UTM), the zone must also be specified. Please contact the NHNM GIS Specialist if you have questions.