Casper Børgesen wrote > This is my syntax: > > gdal_translate -of AAIGrid -ot Float32 -co DECIMAL_PRECISION=2 > my_source.vrt my_target.asc > > I have tried the above syntax using gdal 1.9.2 and 1.10 and these are > examples from my results: > > 1.9.2: > ... > 3.77 3.83 3.89 3.87 3.79 3.49 3.03 2.50 1.96 1.56 1.29 0.95 0.77 0.54 0.53 > 0.41 > ... > > 1.10: > ... > 3.8 3.8 3.9 3.9 3.8 3.5 3 2.5 2 1.6 1.3 0.95 0.77 0.54 0.53 0.41 > ... > > Has the meaning of DECIMAL_PRECISION changed from 1.9.2 to 1.10? > > It seems like in 1.9.2 the meaning is X characters to the right of the > comma and in 1.10 it means X describing characters? > > I haven't tried the 1.10.1 release because I can't find the binaries on > Tamas gisinternals.
Hmm. After a look into the source code [0] and some testing [1], it looks to me that DECIMAL_PRECISION is used as precision of a "%.<precision>g" format. Format letter g means: "Print a number in either scientific notation or in floating-point notation, whichever uses fewer characters." For format letter g, the precision value defines: "Maximum number of *significant* digits." I see there has been this change recently: http://trac.osgeo.org/gdal/changeset/25032/trunk/gdal/frmts/aaigrid/aaigriddataset.cpp Hermann [0] http://trac.osgeo.org/gdal/browser/trunk/gdal/frmts/aaigrid/aaigriddataset.cpp#L1051 [1] # Input file $ cat in.asc ncols 1 nrows 4 xllcorner 1 yllcorner 1 cellsize 1 0.00012345 1.12345678 22.1234567 333.123456 # Test run $ for i in 1 2 3 4 5 ; do echo DECIMAL_PRECISION=$i && gdal_translate -of AAIGrid -ot Float32 -co DECIMAL_PRECISION=$i in.asc out.asc && cat out.asc done # Output DECIMAL_PRECISION=1 ncols 1 nrows 4 xllcorner 1.000000000000 yllcorner 1.000000000000 cellsize 1.000000000000 0.0001 1 2e+01 3e+02 DECIMAL_PRECISION=2 ncols 1 nrows 4 xllcorner 1.000000000000 yllcorner 1.000000000000 cellsize 1.000000000000 0.00012 1.1 22 3.3e+02 DECIMAL_PRECISION=3 ncols 1 nrows 4 xllcorner 1.000000000000 yllcorner 1.000000000000 cellsize 1.000000000000 0.000123 1.12 22.1 333 DECIMAL_PRECISION=4 ncols 1 nrows 4 xllcorner 1.000000000000 yllcorner 1.000000000000 cellsize 1.000000000000 0.0001234 1.123 22.12 333.1 DECIMAL_PRECISION=5 ncols 1 nrows 4 xllcorner 1.000000000000 yllcorner 1.000000000000 cellsize 1.000000000000 0.00012345 1.1235 22.123 333.12 -- View this message in context: http://osgeo-org.1560.x6.nabble.com/gdal-dev-Change-of-DECIMAL-PRECISION-in-AAIGrid-tp5075524p5075585.html Sent from the GDAL - Dev mailing list archive at Nabble.com. _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
