Frequently Asked Questions

Contents:
Data Library Components
Issues With Downloaded Files

Data Library Components

Q: In the tables, what does 'Extent' mean?
A: Many coverages in the Online Data Library are available in two forms, each having a different spatial extent. Coverages listed as clipped are clipped to the Rio Puerco basin boundary. Some parts of the boundaries of some of the portrayed features lie outside of the Rio Puerco basin; those parts of the boundaries external to the basin are not portrayed. In these cases, the basin boundary is substituted for the external boundary. Coverages listed as unclipped contain features that are within the basin boundary, but these features have not been clipped to the boundary. The features that extend outside of the basin boundary are represented.

Q: In the tables, what does 'View the Coverage' mean?
A: Browse images for all coverages are available for viewing online. Most of the coverages in the Online Data Library have many tabular characteristics (attributes) that are not necessarily represented in the browse images included in the library. These images are simply intended to show the user the spatial resolution and extent of the coverages, and to help clarify differences between coverages with similar names.

Q: In the tables, what does 'View the Metadata' mean?
A: Federal Geographic Data Committee (FGDC) compliant metadata records are available in html format for users to read online. These same metadata records are included as text (.txt) files in the Export files and Shapefiles that are available for download.

Q: In the tables, what does 'Get the Coverage' mean?
A: Coverages are available in two different formats (ARC/INFO export files and ArcView/ArcExplorer shapefiles) to accomodate a majority of the users in the GIS community. Users should click here for help decompressing and extracting the data files. Information about using Shapefiles in conjunction with ArcExplorer can be found here.

Q: What is metadata?
A: This online data library provides a way to find information about geospatial or spatially referenced data available for download. The information is in the form of metadata. Metadata, or "information about data," describe the content, quality, condition, and other characteristics about the data. Metadata are used to organize and maintain investments in data, to provide information to data catalogs and clearinghouses, and to aid data transfers.

Issues With Downloaded Files

Q: I downloaded an Export file with my browser, but when I try to import it, I keep getting an error. What's wrong?
A: If you used a browser to download an Export file data set, it may have changed the filename slightly from the original. Sometimes, browsers will mysteriously drop the .gz file extension from the filename. This might give the impression that the file has been automatically decompressed, when in fact it hasn't. If you are having trouble using a data set you downloaded with a browser, make sure the filename hasn't changed. These files must be decompressed before they can be used. If the filename does not have the extension, rename the file and add the .gz extension onto it. Then, use decompression software to unzip the files.

Q: I downloaded a "Shapefile" from the data library. After it was extracted, I got four files. What are these files?
A: Shapefiles typically are made of three pieces: a filename.shp file, a filename.shx file, and a filename.dbf file. The .shp file is the actual shapefile, the .shx file is an index file, and the .dbf file is a dBASE file. The fourth file is a filename.txt file. This .txt file is the metadata record for the GIS layer in a standard ASCII text format.