--- Begin Forwarded Message ---
>Date: Fri, 6 Nov 1998 13:17:28 -0700
>From: Chris Cialek <[log in to unmask]>
>Subject: NSDI_L Putting Data Accuracy Standards to Use
 
 
 
Forward from NSDI-L...might be of interest to others on these lists.
 
Dale
 
 
Anyone who routinely uses USGS quadrangle maps is familiar with the
statement, "This map complies with national map accuracy standards."   The
standards referred to have been in existence since the 1940's and help
provide some indication of the map's quality.
 
Last summer, the United States National Map Accuracy Standards were
replaced with a new standard designed to better represent not just printed
maps, but also the growing number of geographic databases.  This new
standard - the National Standard for Spatial Data Accuracy - provides
guidance in three areas.  The NSSDA:
 
1. Identifies a well-defined statistic used to describe accuracy
2. Describes a method to test spatial data for positional accuracy
3. Provides a way to report that accuracy that makes it easier to evaluate
the fitness for use of a database.
 
The Minnesota Governor's Council on Geographic Information Standards
Committee recently released a draft handbook designed to help explain the
new standard and guide data developers in evaluating the accuracy of their
spatial databases.  "Implementing the National Standard for Spatial Data
Accuracy" explains how positional accuracy can be measured and reported for
databases that contain geographic features like roads, rivers and property
lines.  Five practical examples walk you through the process using
databases developed at the Minnesota Departments of Transportation and
Natural Resources, the City of Minneapolis, Washington County and The
Lawrence Group, a private mapping firm.
 
The handbook, with practical examples and formatted spreadsheets that make
calculating the accuracy statistic easy, can be downloaded in PDF and Excel
formats from the committee's web site:
 
http://www.mnplan.state.mn.us/press/accurate.html .
 
A printed version of the handbook can be ordered through the web site or by
contacting LMIC.
 
Your comments on the material included in the handbook and its overall
usefulness are strongly encouraged and can be directed to Christopher
Cialek at LMIC, phone 651.297.2488, fax 651.296.1212 or e-mail:
[log in to unmask]  Responses received by January 1, 1999 will be used
to refine the handbook for final publication.
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