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Cofrin Center for Biodiversity


It's pretty obvious that a person engaged in GIS work needs to know where their site is located. That's tougher than it sounds because some "languages" and numeric systems essential for defining location are unfamiliar, complicated and downright odd.

Define the Project Footprint
Defining and evaluating a project footprint helps clarify how much work is involved in the project and suggests ways to go at it. Use a paper map, a webmapping application or ArcGIS to draw a figure that includes the locations of all mapping (database building), analytical and map-making activities - then add a generous buffer. Remember, once a project is under way it is easier to shrink the geographic scope than it is to expand it. Eventually you will want to convert your footprint figure to a polygon feature in one of your project-specific spatial databases.

Make a Project Location Checklist
The earth's surface is partitioned in so many ways, it's a wonder it doesn't shatter. Property lines, state boundaries, no-fly zones, neighborhood associations, flood plains and on and on. Of the thousands of partitioning schemes in existence, a few basic ones come up again and again in geographic information systems work. It pays to know what they are, how they work and how to express their relationship to the project footprint. It is a good idea to to work through the following checklist at the beginning of any new project.

  Record the north and south bounding coordinates. These are the lines of latitude that define the northernmost and southernmost extents of the project footprint.
  Record the east and west bounding coordinates.
  List the names of the one-degree blocks intersected by the project footprint.
  List the names and the USGS IDs of the 7½ minute quadrangles intersected by the project footprint.
  List the Worldwide Reference System path and row for scenes intersected by the project footprint (applies to projects utilizing Landsat imagery).
  List the national, tribal, state, etc governments having jurisdiction over the project site.
  List the Public Land Survey System units intersected by the project footprint.
  List the organizations and individuals who own the land intersected by the project footprint. Record owner-imposed restrictions on access and activities.