I would think you would do this through some custom programming using a
little PostGIS backend query based on rectangle extent and some php to
iterate through the query results adding up the areas and then dumping
the summation to an html container in the browser.
but, that's just my approach, someone else might know how to do it
through mapserver's query mechanism, of which I am no expert.
cheers,
percy
Raymond Fu wrote:
hi,
Is it possible and how can I use user map query to generate a
calculated value and ? For example, user draws a recentangle area on
the map, the total number of added value of certain field for all the
feature within the selected area will be displayed on the browser.
Thanks
Raymond
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David Percy
Geospatial Data Manager
Geology Department
Portland State University
http://gisgeek.pdx.edu
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