Geographic Information Systems - GIS

Welcome to the City of Pullman's GIS

The goal of the Geographic Information System (GIS) is to develop location intelligence across the City of Pullman. Location is the common thread connecting the physical and intangible resources of the City. The tools of the GIS enable the City to:

  • Collect location information
  • Visualize, analyze and understand spatial relationships
  • Engage and communicate through maps and mapping applications
  • Connect location information to other business intelligence systems
The City of Pullman GIS portal can be found here:

GIS Map Portal

Data Accuracy

Maps and data on the City of Pullman Geographic Information System (GIS) are representations of real-world conditions. With consideration for the intended use of the map, appropriate effort is made to ensure the accuracy of the data, but errors in mapping and errors in source documents do occur. As such the City of Pullman assumes no liability for errors, omissions or inaccuracies regardless of cause, or for any decision made, action taken, or not taken, as a result of reliance upon any maps.

Potential Sources of Mapping Error

The data contained in basemaps on this site was derived in part by humans, digitizing from aerial imagery and in part by computer algorithms extracting features from aerial imagery. In each case classification errors can occur, obscured features may be missed, and positional accuracy is limited to the resolution of the aerial image.

  • Basemaps are representations of real-world conditions, but confirm on-the-ground conditions before making decisions or acting on information.
Land-base data – city limits, annexations, subdivisions, property, easements, vacations, rights-of-way, zone boundaries, and council wards – are defined by recorded legal documents. Geographic representations do not take the place of these documents, and do not determine ownership rights or property size.

  • The location of property boundaries must be determined by a land surveyor registered to practice in the State of Washington.
Utilities are often underground and difficult to locate. In addition, they are sometimes intentionally drawn to show system connectivity, rather than location accuracy.

  • Utility maps should not be used in lieu of authorized (811) utility locates.
Inventory maps may have incomplete data sets, due to changing conditions. The size of inventoried assets will determine the appropriate mapping scale, and accuracy needs. Some data sets may be created through geocoding, placing assets at a street address, rather than physical locations.

  • Timing, scale, and location method will affect the “accuracy” of a data set.
Maps are presented on a background, or “basemap,” composed of aerial images or schematic representations of actual conditions. On-the-ground conditions may have changed since the photograph was taken, or the schematic created. Location errors in the basemap occur as a result of inescapable compromises made when the 3-dimensionsal earth is represented as a flat map.

  • Even if location data is very accurate, it might look like it is in the wrong place, relative to the basemap.
The City of Pullman GIS utilizes the Washington State Plane South Zone horizontal datum (NAD 83) and NAVD 88 vertical datum transformed from Geoid 12B to collect and store location information. However, most web-based maps will be presented in Web Mercator Auxiliary Sphere projection, causing positional errors in the reprojection. The Web Mercator Auxiliary Sphere projection can cause errors in distance and area measurements.

  • Location errors are unavoidably introduced by representing the earth as a flat map.

Appropriate Map Use

  • DON’T: Make decisions or act without confirming on-the-ground conditions.
  • DON’T: Assume that, because utilities are not shown on a map, that utilities don’t exist in that area.
  • DO: Use maps to help find assets on the ground.
  • DO: Read the Terms of Use specific to each map or data set.
  • DO: Contact City of Pullman GIS with questions regarding accuracy and completeness of maps.
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