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<DIV>I'm sorry,<BR> I know this is a pretty fundamental question to ask
on this list, but I need to ask anyway.<BR> I am trying to understand
geodatabases and how to build an application to work with one. I have
search the Web and read books like Web Mapping Illustrated. I am
famillar with using the GDAL libraries in an application to load a GeoTIFF
image, I have used the utilities like GDAL_translate in a command line
interface and I am very famillar with Shapefiles.</DIV>
<DIV> But I still don't understand the interaction of a C++ windows
application retreving a raster image<BR>from a geodatabase and the role of
the GDAL/OGR libraries in this kind of exchange.</DIV>
<DIV> </DIV>
<DIV> My question is can anyone give me an example of the queries
and the responses when a <BR>visualization application starts with a
geographical rectangle and wants to query a PostGIS database for a raster
image trimmed to fit that rectangle and how the image is returned to the
application ready to be displayed?</DIV>
<DIV> Being more specific....<BR> Is a raster image, like
a landsat image, actually stored in the database, or is the image stored
local to application and represented in the database by a bounding rectangle
and the local filename?</DIV>
<DIV> What happens when the queried rectangle overlaps more than one
database image? How are the pieces composited together into one image?</DIV>
<DIV> My only assumption right now is that the process begins with the
application sending an SQL query through OGR to the PostGIS libraries for
the rectangle in question. Beyond that I'm lost.</DIV>
<DIV> </DIV>
<DIV> Any replies will be appreciated. And if there is a link to a
nuts and bolts kind of tutorial, I would very much appreciate that also.<BR>
Thank you for your time.<BR> --Doug<BR> </DIV></FONT>
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