<div dir="ltr">Do you mean <div><br></div><div><span style="font-size:12.8000001907349px">gdal_translate -te -13813007 5569641 -13809113 5572598</span><br style="font-size:12.8000001907349px"><span style="font-size:12.8000001907349px">srtm_merged_3857.vrt my_subwindow.tif --config GDAL_CACHEMAX 800</span><br></div><div><span style="font-size:12.8000001907349px"><br></span></div><div><span style="font-size:12.8000001907349px">?</span></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Jun 11, 2015 at 3:08 PM, Eli Adam <span dir="ltr"><<a href="mailto:eadam@co.lincoln.or.us" target="_blank">eadam@co.lincoln.or.us</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On Thu, Jun 11, 2015 at 2:38 PM, Ari Simmons <<a href="mailto:ari.ucb.fire@gmail.com">ari.ucb.fire@gmail.com</a>> wrote:<br>
> One notably huge difference is that there is a huge jump in pixel size (from<br>
> 0.000833333333323 to 205.686440189378940)...<br>
><br>
> ah, duh. Unit change.<br>
><br>
> On Thu, Jun 11, 2015 at 2:26 PM, Ari Simmons <<a href="mailto:ari.ucb.fire@gmail.com">ari.ucb.fire@gmail.com</a>> wrote:<br>
>><br>
>> I am experimenting with using 'gdalwarp' on a .vrt (first time), but I'm<br>
>> not sure what I'm doing wrong. I've been running this:<br>
>><br>
>> >> gdalwarp -s_srs EPSG:4326 -t_srs EPSG:3857 -r bilinear -of VRT<br>
>> >> merged.vrt srtm_merged_3857.vrt<br>
>><br>
>> and it processes fast (far far *too fast* for this global file) and<br>
>> returns<br>
<br>
That is the right speed (~0 seconds) and disk space (~0MB). That is<br>
because it doesn't actually do anything except write down notes of<br>
what it would have done (and will do in the future if you ask for it).<br>
I like testing large VRT files by outputting a subwindow tif like<br>
this:<br>
<br>
gdal_translate -13813007 5569641 -13809113 5572598<br>
srtm_merged_3857.vrt my_subwindow.tif --config GDAL_CACHEMAX 800<br>
<br>
If things look good on the subwindow, then it is time for all the I/O<br>
waiting, processor cycles, and storage space. Evaluating a few<br>
places, especially where tiles come together can find things early<br>
without all the wait.<br>
<br>
HTH, Eli<br>
<br>
>><br>
>> >> Creating output file that is 194835P X 479814L.<br>
>> >> Processing input file merged.vrt<br>
>> >> Using internal nodata values (eg. 0) for image merged.vrt<br>
>><br>
>> The return .vrt file definitely doesn't appear right...a quick look at the<br>
>> returned file:<br>
>><br>
>> input:<br>
>><br>
>> Size is 432000, 208800<br>
>> Coordinate System is:<br>
>> GEOGCS["WGS 84",<br>
>> DATUM["WGS_1984",<br>
>> SPHEROID["WGS 84",6378137,298.257223563,<br>
>> AUTHORITY["EPSG","7030"]],<br>
>> AUTHORITY["EPSG","6326"]],<br>
>> PRIMEM["Greenwich",0],<br>
>> UNIT["degree",0.0174532925199433],<br>
>> AUTHORITY["EPSG","4326"]]<br>
>> Origin = (-180.000416666666670,84.000416666666666)<br>
>> Pixel Size = (0.000833333333323,-0.000833333333323)<br>
>> Corner Coordinates:<br>
>> Upper Left (-180.0004167, 84.0004167) (180d 0' 1.50"W, 84d 0' 1.50"N)<br>
>> Lower Left (-180.0004167, -89.9995833) (180d 0' 1.50"W, 89d59'58.50"S)<br>
>> Upper Right ( 179.9995833, 84.0004167) (179d59'58.50"E, 84d 0' 1.50"N)<br>
>> Lower Right ( 179.9995833, -89.9995833) (179d59'58.50"E, 89d59'58.50"S)<br>
>> Center ( -0.0004167, -2.9995833) ( 0d 0' 1.50"W, 2d59'58.50"S)<br>
>> Band 1 Block=128x128 Type=Int16, ColorInterp=Gray<br>
>> NoData Value=0<br>
>> Overviews: 216000x104400, 108000x52200, 54000x26100, 27000x13050,<br>
>> 13500x6525,<br>
>> 6750x3263, 3375x1632, 1688x816, 844x408, 422x204<br>
>><br>
>> and output file:<br>
>><br>
>> Size is 193861, 479814<br>
>> Coordinate System is:<br>
>> PROJCS["WGS 84 / Pseudo-Mercator",<br>
>> GEOGCS["WGS 84",<br>
>> DATUM["WGS_1984",<br>
>> SPHEROID["WGS 84",6378137,298.257223563,<br>
>> AUTHORITY["EPSG","7030"]],<br>
>> AUTHORITY["EPSG","6326"]],<br>
>> PRIMEM["Greenwich",0,<br>
>> AUTHORITY["EPSG","8901"]],<br>
>> UNIT["degree",0.0174532925199433,<br>
>> AUTHORITY["EPSG","9122"]],<br>
>> AUTHORITY["EPSG","4326"]],<br>
>> PROJECTION["Mercator_1SP"],<br>
>> PARAMETER["central_meridian",0],<br>
>> PARAMETER["scale_factor",1],<br>
>> PARAMETER["false_easting",0],<br>
>> PARAMETER["false_northing",0],<br>
>> UNIT["metre",1,<br>
>> AUTHORITY["EPSG","9001"]],<br>
>> AXIS["X",EAST],<br>
>> AXIS["Y",NORTH],<br>
>> EXTENSION["PROJ4","+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0<br>
>> +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs"],<br>
>> AUTHORITY["EPSG","3857"]]<br>
>> Origin = (-19837179.642485119000000,18807657.848855246000000)<br>
>> Pixel Size = (205.686440189378940,-205.686440189378940)<br>
>> Corner Coordinates:<br>
>> Upper Left (-19837179.642,18807657.849) (178d12' 1.50"W, 84d 0' 1.50"N)<br>
>> Lower Left (-19837179.642,-79883575.764) (178d12' 1.50"W, 89d59'58.50"S)<br>
>> Upper Right (20037399.339,18807657.849) (179d59'56.47"E, 84d 0' 1.50"N)<br>
>> Lower Right (20037399.339,-79883575.764) (179d59'56.47"E, 89d59'58.50"S)<br>
>> Center ( 100109.848,-30537958.958) ( 0d53'57.49"E, 89d 2'43.78"S)<br>
>> Band 1 Block=512x128 Type=Int16, ColorInterp=Gray<br>
>> Overviews: 96931x239907, 48466x119954, 24233x59977, 12117x29989, 6059x14995,<br>
>> 3030x7498, 1515x3749, 758x1875, 379x938, 191x471<br>
>><br>
>> One notably huge difference is that there is a huge jump in pixel size<br>
>> (from 0.000833333333323 to 205.686440189378940)...<br>
><br>
><br>
><br>
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</blockquote></div><br></div>