Raster tile indexing in PostGIS

[Fawcett, David]

Kristian, 

You can use a PostGIS query as a tileindex.  Take a look at:
http://mapserver.gis.umn.edu/docs/howto/wms_time_support/#example-of-wms
-t-with-postgis-tile-index-for-raster-imagery

If you are looking for performance, I am guessing that you can do better
with spatially-indexed shapefiles.  Have you created quadtree indexes
for your tileindex shapefile?  Take a look at shptree:
http://mapserver.gis.umn.edu/docs/reference/utilityreference/shptree

David.

-----Original Message-----
From: UMN MapServer Users List [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] On
Behalf Of Thy, Kristian
Sent: Wednesday, November 22, 2006 6:25 AM
To: MAPSERVER-USERS at LISTS.UMN.EDU
Subject: [UMN_MAPSERVER-USERS] Raster tile indexing in PostGIS


Quoting the Raster Data Access HOWTO
<http://mapserver.gis.umn.edu/docs/howto/raster_data>:

"The list of files forming a layer can be stored in a shapefile with
polygons  representing the footprint of each file, and the name of the
files. This is  called a TILEINDEX ..."

The tileindex, we're told, is defined in the map file like this:

LAYER
  NAME "hpool"
  STATUS ON
  TILEINDEX "hp2.shp"
  TILEITEM "Location"
  TYPE RASTER
END

My question is then: Is it possible (and if yes, desirable) to read the
tileindex from a PostGIS data source instead of a shapefile - i.e. use
gdatindex to create the tileindex, then convert the index .shp using
shp2pgsql and stuff it into PostGIS. My understanding is that using
plain ole shapefiles you miss out on the gist indexing and thus suffer a
performance loss.

best regards,
Kristian Thy


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