Digital Geographic Data Needs Assessment (GIS)
Selecting the appropriate data for
your GIS project is an important first step. This worksheet is
designed to help you think through what you are trying to accomplish
and to clarify your data needs. Working through this sheet will help
the Libraries staff give you the data you need in the most efficient
manner. You can also work through this list and leave it for the GIS
Assistant (gis@lib.washington.edu),
who will contact you to make an appointment to retrieve your
data.
- What do you want to do with
the data? Are you creating maps or performing analyses? Are
you mapping streets and bike paths in Seattle, or are you
analyzing distances between the two? Do you need socioeconomic or
demographic data, or physical features? What is the end result you
are trying to reach? Knowing where you want to go will help you
determine what you need to get there.
- What are the specific geographic features you need? Even for a specific
feature like "streets," you may need to describe how you want them
represented (centerlines, double-lined streets, connected routes,
points), the level of detail (all streets, major highways), the level
of generalization or positional accuracy (e.g., major highways at
a "local" scale, such as 1:24,000, or at a "national" scale, such
as 1:3,000,000).
- What attributes of those
features do you need? For streets, you may need
none, some, or all of the following attributes: street name, route
number, road class, road surface class, address ranges, traffic
volume, under or overpass.
- What is the geographic extent
of your area of interest? Do you need data for the State
of Washington, Olympic Peninsula, Puget Sound area, City of
Seattle, Capitol Hill? Census tract, block group, ZIP
code?
- Are parameters such as scale, datum, projection, and coordinate system
important to your application? This can be especially important
when combining data from different sources.
Other things to consider:
- Metadata. Metadata is data about the
data – it provides information about data quality, accuracy,
projection, lineage, etc., and helps you determine fitness for
use. Just as you wouldn't use an unattributed quote in an report,
you don't want to use unverified data in a project.
- File size. Many digital
data sets are several megabytes in size, and will require
sufficient storage space. Does your UW account have room for that
data? Do you know how to request more room? Do you have access to
another server that will accommodate your files?
- Time. Some files you
request may take time to retrieve or generate. Please give staff
ample notice to get your data to you. Many files will be delivered
to you within 48 hours of your request (not including weekends),
with most being delivered much faster.
- Your experience. Are you
performing analyses you've never done before? Are you new to the
software? The Libraries can provide you with data and brief
(approximately one-hour) consultations on your data or projects.
It's a good idea to have a manual on-hand and to utilize the
expertise of your department, if appropriate.
- Your region of study. The
UW Libraries' collection of digital geospatial data concentrates
on the Seattle, Puget Sound, and State of Washington areas. Data
for the rest of the United States and the world is also collected,
but local information is more extensive.
Examples of data themes:
- Agriculture
- Bathymetry
- Demographics
- Economics
- Education
- Fish/Wildlife
- Geology
- Land Use/Land Cover
- Sensitive Areas
- Street Networks
- Topography
- Transportation
- Utilities
- Vegetation
- Wetlands
Last modified: Tuesday January 04, 2005
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