[postgis-users] Create a Thematic grid map with postgresql

[Purvis, Charlton]

> grids from point data on the fly, though it is an interesting idea.

I run a balance between defining a zillion CLASS-es w/ different colors and
constraints to produce a nice image from point data TO pumping point data
into GMT to produce nice images.  I'd suggest you check out GMT if you
haven't already.

This approach is to take either randomly spaced data or a nicely gridded
data set and pump it into a GMT grid.  Create a color table on that, and
then run through a GMT script to produce the image.  Then pass that image
back to MapServer, and away you go.

Our data comes in near real time, but I generate the grids ahead of time.
The only ad-hoc stuff comes in when you're creating the image based on the
user's current extent.

Attached is a very crude example of something we're dealing w/ as we speak.
It's remotely sensed sea surface height data that trickles in near real
time.  I lump them into passes of lots of point data, create the grids, and
then an image like the attached one is created on the fly.  Well, it won't
be like the attached one w/ a colorbar sandwiched improperly, but you get
the idea.  If you're interested, I can pass along some of the code.

Charlton

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