<br><br><div class="gmail_quote">2009/7/11 Frank Warmerdam <span dir="ltr"><<a href="mailto:warmerdam@pobox.com">warmerdam@pobox.com</a>></span><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div class="im">Jorge Arévalo wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hello,<br>
<br>
2009/7/10 Tamas Szekeres <<a href="mailto:szekerest@gmail.com" target="_blank">szekerest@gmail.com</a>>:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Jorge,<br>
<br>
I'm a bit hesitant to think using a server cursor would be the best approach<br>
here. Could you explain why is this needed?<br>
</blockquote>
<br>
Yes. As now I'm working basically with regularly tiled coverages, an<br>
operation like SELECT rast FROM table gives me all the tiles. These<br>
tiles don't overlap, and its size can be the size of a block read for<br>
IReadBlock method. So, if I have a cursor, I can fetch the tile that<br>
the IRasterBlock needs as one of the rows of the resultset without<br>
having all the tiles loaded in memory at same time.<br>
</blockquote>
<br></div>
Jorge,<br>
<br>
I'm not clear on how you know what row to take out of the resultset<br>
for a given IReadBlock() call? How do you translate the x/y block<br>
index into a resultset row offset?<br>
<br>
I would note that spatial searches *should* be quite fast if the<br>
raster row is spatially indexed.<div><div></div><div class="h5"></div></div></blockquote><div><br>Jorge,<br><br>I'm thinking of exactly the same as Frank. It's ok you have the same block size in GDAL as the block size in the database but you might have to construct a different SQL query to select the corresponding block even if a single row is retrieved in a single IReadBlock call.<br>
<br>Best regards,<br><br>Tamas<br><br></div></div><br>