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<DIV><FONT color=#000080 size=2 face=Arial><SPAN class=916121219-12062020>Hi
All,</SPAN></FONT></DIV>
<DIV> </DIV>
<DIV><FONT color=#000080 size=2 face=Arial><SPAN class=916121219-12062020>I have
a large *.tif raster data set ( 92000 * 69000 cells of one meter, projection
EPSG:25832 - ETRS89 / UTM zone 32N )<BR>It contains integer values 1 to 20
and has a file size of about 100 MB in "Byte - Eight bit unsigned
integer" format. <BR>Now the result is a rectangle and I wanted to cut it
down to the area of interest (via cutline gdal option) using a shape
polygon file (with one continuous polygon inside) to and set all values outside
the area of interest of that rectangle to NULL values (for example
setting 0 as NULL data values). I used the QGIS ( QGIS v 3.12 on
windows) Menu RASTER > Extraction > Clip Raster by mask Layer which
is based on gdalwarp.<BR></SPAN></FONT></DIV>
<DIV><FONT color=#000080 size=2 face=Arial><SPAN class=916121219-12062020>That
is when I am running into the problem that the 'cut' file size increases
enormously and I ended up wit 50 times bigger file ( 5 GB size ! ) when I
was actually expecting a smaller file size than before.</SPAN></FONT></DIV>
<DIV><FONT color=#000080 size=2 face=Arial><SPAN class=916121219-12062020>I have
not really an idea why the file becomes so enormously bloated. The
same is the cass when I try gdalwarp directly on the command line or when using
the QGIS Raster calculator or any other method I tried so
far.</SPAN></FONT></DIV>
<DIV><FONT color=#000080 size=2 face=Arial><SPAN
class=916121219-12062020></SPAN></FONT> </DIV>
<DIV><FONT color=#000080 size=2 face=Arial><SPAN class=916121219-12062020>How
can I manage to get a smaller file size ( aka the 100 MB file size I started of
with ) and which tools or formats are recommended to achieve this
?</SPAN></FONT></DIV>
<DIV><FONT color=#000080 size=2 face=Arial><SPAN
class=916121219-12062020>Cheers</SPAN></FONT></DIV>
<DIV><FONT color=#000080 size=2 face=Arial><SPAN
class=916121219-12062020>Karsten</SPAN></FONT></DIV>
<DIV><FONT color=#000080 size=2 face=Arial><SPAN
class=916121219-12062020></SPAN></FONT> </DIV>
<DIV><SPAN style="FONT-SIZE: 11pt; FONT-FAMILY: 'Verdana','sans-serif'">Karsten
Vennemann<BR></SPAN><SPAN
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blocked::http://www.terragis.net/"
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