GIS Data

This is the launch page for finding information about GIS data: what is GIS data, what are the different types of GIS data, what are errors in GIS data, metadata, and where to find GIS data on the Internet.

Introduction to GIS Data

Geodatabases Explored – Vector and Raster Data
Vector and raster data types (including aerial and satellite imagery) are described.

GIS Data: A Look at Accuracy, Precision, and Types of Errors
What is the difference between precision and accuracy?  What types of errors are found in GIS data?  Learn more about error in GIS data.

GIS Data Formats
What are the common GIS file formats?  This article describes shapefiles, GML, CAD based file formats, and imagery formats.

What is a Basemap?
Basemaps are creating by combining GIS data to form the background layer of a map.

Satellite Imagery
Article from 2001 briefly describing satellite imagery and a list of (then) available satellite imagery sources.

Orthophotos
Information about aerial imagery and orthorectification.

Understanding GIS Error
Understanding error in GIS data is an important part of GIS analysis.

Metadata
Metadata, known as “data about the data” is critical documentation about GIS data.

GIS Data Creation and Analysis

Methods for Creating Spatial Databases
How is GIS data created?  Read here about some of the methodology including heads up digitizing, COGO, and geocoding.

Finding GIS Data Sources on the Internet

The Internet has a wealth of sources of downloadable GIS data.  Below is information about GIS data warehouses and other sources of GIS data.

African Data
Data sources, both commercial and free, in GIS format of Africa. Find cadastral, environmental and cultural data.

Airport Data and GIS Resources
Links to airport location data, associations and articles on the use of GIS in the aviation industry.

Census Data
Links to Census related datasets. Sources include TIGER files.

Data Warehouses
Resources to web sites that host large amounts of datasets both at the nationwide (United States) and global levels. Most of the data is available for free or for little cost.

Digital Elevation Models
Links to Digital Elevation Model datasets.

GIS File Formats
Guides to the various file formats and tools for data format conversions.

Imagery
Digital imagery can greatly add to the visualization of GIS data. In addition satellite imagery can be utilized to derive layers via classification processes such as vegetation, land cover and temperature.

North American Tribal Data
Free sources of data for North American Tribal regions.

Time Zone Data
Free and commerical sources of Time Zone Datasets.

Urban Landuse Data
Free download sites for obtaining urban land use datasets.

World Data
Free and low-cost sources of data for globally based datasets.

(Article originally published: February 2, 2005)