I got this working this morning. Again, I simply need to explore the documentation better! My issue was not with format or projection, but with image size. My final mosaic kept hitting the 3.7GB mark, regardless of whether I used a .vrt, a GTiff, or worked with gdalwarp.<div>
<br></div><div>Reading the GTiff driver documentation, I needed to set BigTiff to yes.</div><div><br></div><div>Thanks all who responded. Using a vrt definitely sped the process as I no longer needed to batch translate from IMG to tif.</div>
<div><br></div><div><br></div><div><br><div class="gmail_quote">On Fri, Oct 7, 2011 at 6:59 PM, Chaitanya kumar CH <span dir="ltr"><<a href="mailto:chaitanya.ch@gmail.com">chaitanya.ch@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">Jay,<br><br>The gdal_merge script needs the images to match in the coordinate system and the number of bands.<br><br>One likely problem is could be different data types. Provide the gdalinfo outputs of the images.<br>
<br><div class="gmail_quote">
Before you try that, use the gdalbuildvrt program to create a vrt file
and then gdal_translate to convert the vrt file into a single image. The result is
usually the same.<div><div></div><div class="h5"><br>
<br>On Fri, Oct 7, 2011 at 9:12 PM, Jay L. <span dir="ltr"><<a href="mailto:jzl5325@psu.edu" target="_blank">jzl5325@psu.edu</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204, 204, 204);padding-left:1ex">
<div><div></div><div class="h5">
<div class="gmail_quote"><div class="gmail_quote">Sent with an example attachment, which is awaiting approval. Here is the mail without attachement.</div><div class="gmail_quote"><br></div><div class="gmail_quote"><br></div>
<div class="gmail_quote">
I have 8 large Gtiffs which I am trying to mosaic. Tiffs were created from .IMG files downloaded from PDS. I converted to tif using:<div><br></div><div> gdal_translate -of GTiff -scale -co "TILED=YES" -co "COMPRESS=JPEG" <input></div>
<div><br></div><div>The format conversion is working without a problem. Gdalinfo is reporting the correct NDV and projection information. Viewing each tif also returns the expected raster iamge. So far, so good.</div>
<div>
<br></div><div><br></div><div>I then use:</div><div><br></div><div> gdal_merge.py -o wacmos.tif -of GTiff -v --optfile tiff_list.txt </div><div><br></div><div><br></div><div>Six of the eight tiles are added to the mosaic correctly. Varying the order in the list, or using *.tif does not change the output. It is always the same two images which are missing. Watching the verbose output, it looks like the images are mosaicing correctly. What would cause these images to be merged as totally black tiles?</div>
<div><br></div><div><br></div><div>Thanks for any insight, </div><div>Jay</div><font color="#888888"><div><br></div><div> </div>
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<br></div></div><div class="im">_______________________________________________<br>
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<a href="http://lists.osgeo.org/mailman/listinfo/gdal-dev" target="_blank">http://lists.osgeo.org/mailman/listinfo/gdal-dev</a><br></div></blockquote></div><font color="#888888"><br><br clear="all"><br>-- <br>Best regards,<br>
Chaitanya kumar CH.<br>
<br><a href="tel:%2B91-9494447584" value="+919494447584" target="_blank">+91-9494447584</a><br>17.2416N 80.1426E<br>
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