John,
I think by following Frank's advice and using a PostGIS-hosted tile-
index you can do a hell of a lot by manipulating your DATA statement
to get the images you want for a given request. Things like temporal
subsetting, etc, are all pretty easy. You don't even need to use
mapscript, just override your DATA statement with a parameter in the
mapserv CGI. (I think mapscript is largely irrelevant given the
capabilities of the CGI system, personally.)
Paul
On 25-Aug-06, at 9:55 PM, Frank Warmerdam wrote:
John Novak wrote:
I have a large number of rows containing metadata about rater
files sitting in a PostGIS table. Each row is associated with a
georeferenced file sitting in a file system, and the row contains
polygon geometry representing the footprint of the raster. The
rows also contain many other attributes that I'd like to use to
filter the displayed rasters.
Having the functionality of the RASTER layer, but using a PostGIS
table as a source for features rather than a SHAPEFILE would be a
very useful thing, at least in my case.
>
What's the opinion regarding
1. the overall usefulness of such a beastie
and
2. the complexity of actually implementing said beastie, given
that it's a combination of the functionality of a PostGIS layer
and a RASTER layer ?
I admit I have not done my homework and really examined the code
for these two layers.
John,
It is currently possible to use a postgis table as a "tile index" for
a raster layer. To do so, configure the postgis table as a
distinct layer,
and use the name of that layer in the TILEINDEX keyword of your
raster layer
instead of the name of an external shapefile.
The raster layer will do a spatial query on the tileindex table to get
a list of rasters to plot.
I'm a bit fuzzy on how you would do other sorts of query operations.
It is possible a FILTER on the tileindex layer will be preserved as
part of the tileindex query, but I'm not absolutely sure. Of course,
you could put complex query logic right into your DATA statement on
the postgis layer.
Best regards,
--
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I set the clouds in motion - turn up | Frank Warmerdam,
[EMAIL PROTECTED]
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush | President OSGeo, http://
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