<br><br><div><span class="gmail_quote">On 9/26/06, <b class="gmail_sendername">Frank Warmerdam</b> <<a href="mailto:warmerdam@pobox.com">warmerdam@pobox.com</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Frederico Lucca wrote:<br>> Hello list,<br>><br>> Can I reproject a image that is inside a layer using tileindex?<br><br>Frederico,<br><br>Yes.<br><br>> My problem is that I need to show a ECW that is in Corrego Alegre Datum.
<br>> First of all I tried to use<br>> PROJECTION<br>> "init=epsg:4225"<br>> END<br>> without success.<br><br>To be clear, are the bounds stored in the tile index in degrees?<br>(as opposed to projected meters, feet, etc)
</blockquote><div><br>Frank,<br><br>Yes, the bounds are stored in degrees, with Corrego Alegre datum. Almost the same as WGS84, in some places with difference of 60 meters from one to other.<br> </div><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
> Than I tried to use gdalwarp to convert it to WGS84 that is my map<br>> Datum, but I can't write ECW format, why not?<br><br>The gdalwarp program processes the image in chunks, but the ECW<br>writer (and also many other compressed GDAL drivers) only support
<br>line by line copying, so gdalwarp has to output to a "working file",<br>which can then be converted to ecw using gdal_translate. I often<br>use GeoTIFF or Imagine (HFA) formats for working files.</blockquote>
<div><br>Great! The problem is the hard disk space, I have more than 1000 images and no space. Each GeoTiff have 100.000 MB and compressing with ECW 10.000 MB.<br> </div><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
> So, the only solution I found is convert using gdalwarp exporting as<br>> GTiff, but the image size is very large.<br>><br>> I have many photos and want to use only a layer if is possible.<br>> There is a solution?
<br><br>Generally speaking, if all your photos are in EPSG:4225 you should be<br>able to just label the layer that way, and your map as EPSG:4326, and<br>mapserver will take care of reprojecting the images as needed.<br><br>
However, you cannot have a mix of coordinate systems in your tile index.<br>So this only works if all the images in your tile index are in the same<br>coordinate system.</blockquote><div><br>Ok, all my images have the same coordinate system.
<br> </div><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">There is a performance cost to reprojecting rasters on the fly. You<br>may still find you are better pre-reprojecting them using gdalwarp,
<br>and then recompressing to ECW with gdal_translate.</blockquote><div><br>Ok, I will try, thanks a lot. <br><br>Fred.<br></div><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Good luck,<br>--<br>---------------------------------------+--------------------------------------<br>I set the clouds in motion - turn up | Frank Warmerdam, <a href="mailto:warmerdam@pobox.com">warmerdam@pobox.com</a><br>
light and sound - activate the windows | <a href="http://pobox.com/~warmerdam">http://pobox.com/~warmerdam</a><br>and watch the world go round - Rush | President OSGeo, <a href="http://osgeo.org">http://osgeo.org</a><br>
<br></blockquote></div><br><br clear="all"><br>-- <br>"Everything under the sun is in tune<br>But the sun is eclipsed by the moon"