clipgdalqgisqgis-2
I have a geo-tiff created by Pix4D which is about 375 Mb in file size.
I have clipped it to a smaller area using Qgis 2.8(using Raster ‣ Extraction ‣ Clipper), and the output file is about 900 MB in size.
Why did the clipping process generate such a large file, when the source file was smaller?
How do I run the clipper tool so that it produces a smaller size?
It seems a SRS problem. What's the coordinate reference system of your project? Your x coordinates seem wrong.
Note that clipper tool (from raster menu) distort your output, or may distort it by changing cell size. My suggestion is to use the clipper under gdal tools from the toolbox.
There define -tr resx, resy in the additional parameters window; where both resx & resy > 0. Those stand for the input raster resolution, and forces the output to keep it. You can get the resolution from the properties>metadata of your input raster. Note that it will be written like this: 30.0, -30.0; thus modify it to be 30.0, 30.0.
The image below sum it up with an example:
Best Answer
The Clipper tool makes an uncompressed image by default. Read the GDAL manual of your format and add manually the compression options into the gdal_translate command that is shown in the lowest pane.
For example for GeoTIFF read http://gdal.org/frmt_gtiff.html and use for example
-co COMPRESS=DEFLATE -co PREDICTOR=2which gives a well compressed, lossless output for topographic maps.If you think that it would be trivial to add compression options to the user interface of the Clipper tool it is not because more than 30 formats are supported for the output and all of them have different settings for compression if compression is supported at all.