WAIS through the Web - Discovering Environmental Information

Wide Area Information Servers (WAIS)

Wide Area Information Servers [WAIS] index each word in every readable file and provide the means to make the index available for query, process queries and deliver results.

The freeWAIS-sf distribution from University of Dortmund [freeWAIS-sf] is well suited to preparing a spatial data directory because it is designed to index certain structured fields. In the case of our test server we are indexing five fields:

• the four edges of a minimum bounding rectangle of each data set
  • northernmost latitude
  • southernmost latitude
  • easternmost longitude
  • westernmost longitude
• data set theme

freeWAIS allows boolean queries which means that one can search for combinations of words in the text. Such a query might be "(river or ocean) and (pollution or toxic or waste)".

Multiformat capabilities allow a data set to be presented as a suite of files. For every data set that WAIS discovers Mosaic can present each of the following associated files:

• a metadata text file
• World_Heritage_Areas.TEXT
• an image of the spatial data set
• World_Heritage_Areas.GIF
• a prepared map complete with sources and caveats as a postscript file
• World_Heritage_Areas.PS
• an HTML document with a list of absolute links to relevant documents available on the World Wide Web
• World_Heritage_Areas.HTML
• a compressed archive file of the complete data set including actual spatial information (the bits and bytes - perhaps an ARC/INFO GIS export file)
• World_Heritage_Areas.TGZ

If other sites around the world that deal with environmental information used the same names for metadata fields then queries on, for example, the "NOAA Data Set Catalog", the "USGS Spatial Data Discovery System", and the "ERIN Distributed Spatial Data Library" could be carried out concurrently.

Additional technical documentation is under continuous development at ERIN to help with setting up a spatial multiformat WWW-WAIS gateway [ERIN3].

Further references to documentation about WAIS can be found at ERIN's list of "References for Spatial Search and Retrieve" [ERIN4].