[Mapserver-users] Mapserver and POSTGIS and RASTER layer

[Bob Basques]

Rosangela,

I've been playing around with this exact same scenario, only as a
seperate service , and then combining the results with  Mapserver (or
any other image service for that matter).  Not to get too far off topic,
but I handle the integration with a combination of server and client
side operations.

I build a tiled dataset (or datasets) to accomplish this task with a
dedicated (raster) image server.  Then the mapping info from say a
MAPserver can be overlaid (with the appropriate transparent colors set)
onto the raster image.

See here if interested in getting some ideas:

       http://pwultra5.ci.stpaul.mn.us/cgi-bin/drill/req.02.pl
(NOTE: the Zoom out function isn't completed yet. hence the "Top Level"
link  :c)

This is an experiment for the very purpose that is described in this
thread, pulling in a tiled raster dataset (many levels in this example,
there are 6 levels of resolution in all)

Another version:

     http://pwultra5.ci.stpaul.mn.us/cgi-bin/drill/req.lights.01.pl

This version also has an overlay for the Lighting network at the next to
last zoom level.

Check the underlying page code, it may give you some alternate ideas.


The idea was to make a raster image interface with a major emphasis on
speed of downloads.  It's not obvious with this example, but the
Viewport (area of viewable image) can be resized, and the appropriate
tiles will be downloaded as needed for each level of resolution,
currently there should be no more than four tiles per theme being
downloaded. the source tiles are all 1000 pixels square regardless of
zoom level, there's just more of them the further in you zoom.

Again, this is an experiment in progress, don't be surprised if
something doesn't owrk right off.  It does require IE5+ currently, but
it can be made to run cross browser.



bobb



Paul Ramsey wrote:

 > Rosangela,
 > No, it's not possible with the current PostGIS and Mapserver. Your
 > description is a very good "use case" for how such a functionality
 > might be made to work. Would you like to fund the R&D to make it
 > possible? If others are also interested in this capability, a jointly
 > funded development project could share the expense of adding the new
 > capability to PostGIS and Mapserver.
 > Yours,
 > Paul
 >
 > Rosangela Silva wrote:
 >
 >> Hello,
 >>
 >> I'd like to use mapserver with posgis for manipulate raster data
 >> and I'd like to know if is possible to do this:
 >> - pass a variable to a MAP FILE (in execution time) into a SQL SELECT
 >> - mosaic some blobs resultant of an SQL SELECT
 >>
 >> Something like this:
 >>
 >>  LAYER #Raster
 >>    CONNECTIONTYPE postgis
 >>    NAME "sp_images"
 >>    CONNECTION "user=postgresql password="" dbname=gisdb host=localhost"
 >> =>>>   DATA " SELECT data from sp_image where sp_image.the_geom &&
 >> EXTEND "
 >>    STATUS DEFAULT
 >>    TYPE RASTER
 >>         OFFSITE 0
 >>   END
 >>
 >> " SELECT data from sp_image where sp_image.the_geom && EXTEND "
 >>
 >> data is of blob type and the select probably result a number of
 >> blobs registers. I'd like to mosaic this blobs and form an raster layer
 >> on execution time. The EXTEND is a variable passed in execution time
 >> with MapServer extend box request.
 >> Is it possible??
 >>
 >> Thanks in advance,
 >>
 >> Rosangela.
 >
 >
 >