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GIS

The Map Collection has recently obtained geographical information system (GIS) software for general use. These packages include ArcView, Census CD, Maptitude, and StreetAtlas USA.

What is GIS?
What can be done with a GIS package?
GIS at the Map Collection
GIS at Yale


What is GIS?

A GIS system is an information system that is designed to work with data referenced by spatial or geographic coordinates. It refers to the software, hardware, and procedures that process the information requested.

What can be done with a GIS package?

Once you have a GIS software package, a computer, and some data (maps, etc.), you can do many things. Digitizing data is a large component of this: it involves taking a paper map (or hardcopy) of your information and scanning it into digital format. Scanning just saves your map as an image. You can't do much with it at that point - it is more like a photograph.
However, once you have a scanned image, you can proceed to digitize it. This involves allowing the computer to identify many of the points, lines, and polygons on the map. Digitizing can be a very time-consuming process.
Once a map is digitized, it can be geo-coded. This means that the GIS program "knows" each point's latitude and longitude, so that this map can be overlain with another map and the location will be aligned in both maps.
It is possible to have maps of various uses (land use, topography, roads, human habitat, etc.) for a given area. Each of these acts as an independent layer, and can be adjusted. However, multiple uses can be found by combining two or more layers. For example, topography, land use, and rainfall pattern layers can be combined to find areas that may be flooded.

GIS at the Map Collection

The Map Collection has the following software:

  • ArcView version 3.1 on a Windows95-based computer.
  • ESRI data and maps; includes world and US data at different levels and of various types (census, topographical, zip code, etc.).
  • ArcUSA - detailed data on the US
  • ArcWorld - detailed data on non-US regions
  • CensusCD+Maps - a US-based database of census information
  • Maptitude
  • Street Atlas USA 5.0

It also has the tutorial "Getting to Know Desktop GIS", which gives a detailed description of what GIS is and how to use a number of data sources within the ArcView package. This is a great resource for beginners.

The following data is also available:

USA :

  • Census and statistics
  • Topographical
  • Rivers and waterways
  • Highways and roads
  • Zip codes
  • Boundaries
  • Socioeconomic data

World:

  • Boundaries
  • Demographic attributes
  • Lakes and rivers
  • Statistical attributes (limited)

The world data is less detailed than that of the US, and is at a lower resolution.

GIS at Yale

There are a number of locations at Yale that have GIS software and facilities, and the most common software package is ArcView. For more information, see Digital Mapping, which gives a brief overview of GIS resources at Yale.


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http://www.library.yale.edu/MapColl/gis.html
Last updated August 22, 2000.