<div dir="ltr">I've translated the ASCII with gdal_translate and I get a reasanable size, 335 MB.<div>The other Geotiff was exported with ano</div><div>ther software.</div><div>My question is what, inside the Geotiff structure, can make them so different in size when gdalfino reports the same dimensions and cell type?</div>
<div><br></div><div>giovanni</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">2014-07-05 16:02 GMT+02:00 G. Allegri <span dir="ltr"><<a href="mailto:giohappy@gmail.com" target="_blank">giohappy@gmail.com</a>></span>:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">I've converted a Float32 ASCII Grid of 8861 x 9457 cells to Geotiff (with deflate compression, predicor=1). <div>
The original file was 577 MB, the resulting Geotiff is about 1.897 MB.</div><div><br></div>
<div>Here is gdalinfo run on the ASCII:</div><div><br></div><div><div>Driver: AAIGrid/Arc/Info ASCII Grid</div><div>Files: DTM\dtm.asc</div><div> DTM\dtm.asc.aux.xml</div><div>Size is 8861, 9457</div><div>Coordinate System is `'</div>
<div>Origin = (1634712.000000000000000,4904391.000000000000000)</div><div>Pixel Size = (10.000000000000000,-10.000000000000000)</div><div>Corner Coordinates:</div><div>Upper Left ( 1634712.000, 4904391.000)</div><div>Lower Left ( 1634712.000, <a href="tel:4809821.000" value="+14809821000" target="_blank">4809821.000</a>)</div>
<div>Upper Right ( 1723322.000, 4904391.000)</div><div>Lower Right ( 1723322.000, <a href="tel:4809821.000" value="+14809821000" target="_blank">4809821.000</a>)</div><div>Center ( 1679017.000, 4857106.000)</div><div>
Band 1 Block=8861x1 Type=Float32, ColorInterp=Undefined</div><div>
Min=5.810 Max=1932.780</div><div> Minimum=5.810, Maximum=1932.780, Mean=393.467, StdDev=316.141</div><div> NoData Value=-99</div><div> Metadata:</div><div> STATISTICS_MAXIMUM=1932,78</div><div> STATISTICS_MEAN=393,46740210782</div>
<div> STATISTICS_MINIMUM=5,81</div><div> STATISTICS_STDDEV=316,<a href="tel:14065359461" value="+14065359461" target="_blank">14065359461</a></div><div><br></div><div>And here the Geotiff:</div><div><br></div><div>
<div>Driver: GTiff/GeoTIFF</div><div>Files: dtm.tif</div><div>Size is 8861, 9457</div>
<div>Coordinate System is:</div><div>PROJCS["Monte Mario / Italy zone 1",</div><div> GEOGCS["Monte Mario",</div><div> DATUM["Monte_Mario",</div><div> SPHEROID["International 1924",6378388,297.0000000000014,</div>
<div> AUTHORITY["EPSG","7022"]],</div><div> AUTHORITY["EPSG","6265"]],</div><div> PRIMEM["Greenwich",0],</div><div> UNIT["degree",0.0174532925199433],</div>
<div> AUTHORITY["EPSG","4265"]],</div><div> PROJECTION["Transverse_Mercator"],</div><div> PARAMETER["latitude_of_origin",0],</div><div> PARAMETER["central_meridian",9],</div>
<div> PARAMETER["scale_factor",0.9996],</div><div> PARAMETER["false_easting",1500000],</div><div> PARAMETER["false_northing",0],</div><div> UNIT["metre",1,</div><div> AUTHORITY["EPSG","9001"]],</div>
<div> AUTHORITY["EPSG","3003"]]</div><div>Origin = (1634712.000000000000000,4904391.000000000000000)</div><div>Pixel Size = (10.000000000000000,-10.000000000000000)</div><div>Metadata:</div><div> AREA_OR_POINT=Area</div>
<div>Image Structure Metadata:</div><div> COMPRESSION=DEFLATE</div><div> INTERLEAVE=BAND</div><div>Corner Coordinates:</div><div>Upper Left ( 1634712.000, 4904391.000) ( 10d41'17.17"E, 44d16'46.14"N)</div>
<div>Lower Left ( 1634712.000, <a href="tel:4809821.000" value="+14809821000" target="_blank">4809821.000</a>) ( 10d39'51.33"E, 43d25'42.21"N)</div><div>Upper Right ( 1723322.000, 4904391.000) ( 11d47'50.78"E, 44d15'27.69"N)</div>
<div>Lower Right ( 1723322.000, <a href="tel:4809821.000" value="+14809821000" target="_blank">4809821.000</a>) ( 11d45'28.67"E, 43d24'26.04"N)</div>
<div>Center ( 1679017.000, 4857106.000) ( 11d13'36.91"E, 43d50'40.36"N)</div><div>Band 1 Block=8861x1 Type=Float64, ColorInterp=Gray</div><div> NoData Value=-99</div></div><div><br></div><div>giovanni</div>
<span class="HOEnZb"><font color="#888888">
<div><br></div>-- <br><div dir="ltr">Giovanni Allegri<br><a href="http://about.me/giovanniallegri" target="_blank">http://about.me/giovanniallegri</a><div>Twitter: <a href="https://twitter.com/_giohappy_" target="_blank">https://twitter.com/_giohappy_</a></div>
<div>blog: <a href="http://blog.spaziogis.it" target="_blank">http://blog.spaziogis.it</a><br>GEO+ geomatica in Italia <a href="http://bit.ly/GEOplus" target="_blank">http://bit.ly/GEOplus</a></div></div>
</font></span></div></div>
</blockquote></div><br><br clear="all"><div><br></div>-- <br><div dir="ltr">Giovanni Allegri<br><a href="http://about.me/giovanniallegri" target="_blank">http://about.me/giovanniallegri</a><div>Twitter: <a href="https://twitter.com/_giohappy_" target="_blank">https://twitter.com/_giohappy_</a></div>
<div>blog: <a href="http://blog.spaziogis.it" target="_blank">http://blog.spaziogis.it</a><br>GEO+ geomatica in Italia <a href="http://bit.ly/GEOplus" target="_blank">http://bit.ly/GEOplus</a></div></div>
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