Hi David,
Here's a crazy idea could you perhaps use mm and then output to an integer
raster? No problem representing 50597mm.
I like you thinking! But on reflection suspect that would confound a few
too many of our users. It's certainly a nice lateral-thinking solution to
bear in mind for
On 03/12/2014 06:58 AM, Jonathan Moules
wrote:
Hi David,
Here's a crazy idea could you perhaps use mm and then
output to an integer raster? No problem representing
TIFF stores floating point values as IEEE754 floats. Talking about
significant
figures doesn't make much sense. You could test using Float64 with the hope
that 50.597 can be exactly represented as a Float64. Otherwise you'll have
to
do the rounding when reading back from TIFF.
Hi Even,
Hi Even,
Thanks for the information. I don't pretend to understand the fine details
of floats, but it does seem counter intuitive that a simple 2 or 3 decimal
places can't be accurately represented.
Yes this is really counter intuitive. I've just tested with the Python console
that 50.597
Hi Even,
Thanks for the information.
I tried the Float64 but the values are identical (16 significant figures)
even though the filesize is predictably larger.
I guess I'll have to make do, but it does introduce the problem of False
Precision.
Very few formats take into account
On 03/11/2014 02:06 AM, Jonathan Moules
wrote:
TIFF stores floating point values as IEEE754 floats.
Talking about significant
figures doesn't
Hi List,
Bringing back an old thread but with a slight change.
I'm now trying to get GDAL to mosaic and export from the ASCII files to a
GeoTIFF.
But the GeoTIFF writer in GDAL is doing the exact same thing as the ASCII
writer was - it's taking *50.597* (source value) and converting it into
Have you tried using a 36bit (float) instead of 64bit (double) output?
double is usually the default output type and has more significant digits
(~16) than your source, so it's representation is ok in double format
see [1] for an explanation on floating-point precision
the following argument
Hi Etienne,
I was looking for something like that but the
http://www.gdal.org/frmt_gtiff.html page didn't list it explicitly.
That said, looking at the gdalinfo now (a little late) I see that it's
already defaulting to Float32. I also tested with the -ot Float32
arguement, but there was no
Le lundi 10 mars 2014 18:55:36, Jonathan Moules a écrit :
Hi Etienne,
I was looking for something like that but the
http://www.gdal.org/frmt_gtiff.html page didn't list it explicitly.
That said, looking at the gdalinfo now (a little late) I see that it's
already defaulting to Float32. I
Hi,
I restored DECIMAL_PRECISION and added SIGNIFICANT_DIGIT and also
reformatted the NODATA_value, although that may or may not be correct
as per Even's remarks. See:
http://trac.osgeo.org/gdal/ticket/3732
for a review.
On Mon, Mar 10, 2014 at 1:21 PM, Even Rouault
Le vendredi 24 janvier 2014 23:03:24, Hermann Peifer a écrit :
On 2014-01-24 17:22, Norman Vine wrote:
hmm
this seems to be related to this fairly recent change
http://trac.osgeo.org/gdal/ticket/3732
http://osgeo-org.1560.x6.nabble.com/gdal-dev-Change-of-DECIMAL-PRECISION-
Hi List,
I'm trying to mosaic some ASCII grid tiles into a single large ASCII file
(which can then easily be handled).
I'm using this process:
REM Create list of files
dir /b /s *.asc asc_list.txt
REM Turn into VRT
gdalbuildvrt -srcnodata - -vrtnodata 0 -a_srs EPSG:27700
try
gdal_translate -of AAIGrid -co DECIMAL_PRECISION=3 abc.vrt abc.asc
see http://www.gdal.org/frmt_various.html
HTH
Norman
On Jan 24, 2014, at 10:01 AM, Jonathan Moules
jonathanmou...@warwickshire.gov.uk wrote:
Hi List,
I'm trying to mosaic some ASCII grid tiles into a single large ASCII
Thanks Norman. I'd already seen that page but failed to read it!
However, having tested it, it's not functioning as the manual says.
As best I can tell, DECIMAL_PRECISION=3 should give me 3 decimal places.
But what it instead does it give me 3 significant figures. So 98.354 has
become 98.3.
This
hmm
this seems to be related to this fairly recent change
http://trac.osgeo.org/gdal/ticket/3732
http://osgeo-org.1560.x6.nabble.com/gdal-dev-Change-of-DECIMAL-PRECISION-in-AAIGrid-td5075524.html
don't know much more
Norman
On Jan 24, 2014, at 11:12 AM, Jonathan Moules
On 2014-01-24 17:22, Norman Vine wrote:
hmm
this seems to be related to this fairly recent change
http://trac.osgeo.org/gdal/ticket/3732
http://osgeo-org.1560.x6.nabble.com/gdal-dev-Change-of-DECIMAL-PRECISION-in-AAIGrid-td5075524.html
I am just repeating what I wrote in the above-mentioned
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