Hi,
Another method to reproduce without Python by using gdal_create:
gdal_create -outsize 100 100 -ot float32 -a_nodata nan -of hfa nan.img
C:\data\000\gdaltest>gdalinfo nan.img
Warning 1: NaN converted to INT_MAX.
Driver: HFA/Erdas Imagine Images (.img)
Files: nan.img
Size is 100, 100
...
Band 1 Block=64x64 Type=Float32, ColorInterp=Undefined
Description = Layer_1
NoData Value=nan
Metadata:
LAYER_TYPE=athematic
If I convert nan.img into GeoTIFF with "gdal_translate nan.img nan.tif", I do
see the warning, but the new GeoTIFF still has NoData Value=nsn. I wonder what
is the real meaning of the warning.
-Jukka Rahkonen-
________________________________________
Lähettäjä: gdal-dev käyttäjän Jason Roberts via gdal-dev puolesta
Lähetetty: Perjantai 9. toukokuuta 2025 2.04
Vastaanottaja: Even Rouault; gdal dev
Aihe: Re: [gdal-dev] HFA (.img) driver prints Warning 1: NaN converted to
INT_MAX when float raster has nan as the NoData value
Thank you. I can help you repro it if you want to take a look.I'm having
trouble attaching a .img file to email. My email system doesn't want to allow
it, even if I put it in a zip. But here is a simple way to repro it by creating
the file with GDAL itself. (In this example, I used float64 and the same
warning occurs.) You could use this to produce a test file. If you'd prefer I
send a file I can post it to a file exchange service.>>> import numpy as
np>>>>>> from osgeo import gdal>>> print(gdal.__version__)3.9.2e>>>
gdal.UseExceptions()>>>>>> # Create the dataset as float64 with 1 band>>> f =
'has_nans.img'>>> drv = gdal.GetDriverByName('HFA')>>> ds = drv.Create(f, 100,
100, 1, gdal.GDT_Float64)>>>>>> # Make some fake data; set some cells to nan,
although this is not necessary to repro the warning>>> data =
np.arange(100*100, dtype=float).reshape(100,100)>>> data[0:20,0:30] =
float('nan')>>>>>> # Write the data to the band>>> band =
ds.GetRasterBand(1)>>> band.SetNoDataValue(float('nan'))0>>>
band.WriteArray(data, 0, 0)0>>>>>> # Close the dataset>>> del band, ds>>>>>> #
Open it again - warning happens here>>> ds = gdal.Open(f,
gdal.GA_ReadOnly)Warning 1: NaN converted to INT_MAX.JasonOn 5/8/25 18:39, Even
Rouault wrote:There are metadata fields that the HFA driver opens. That must
come from that. Always shutting down the warning could be inappropriate, but
perhaps in the context where the warning is emitted the driver could avoid
emitting it. But we need to have access to the file to better understand the
call path.Le 09/05/2025 à 00:35, Jason Roberts a écrit :Hi Even,Thanks. I can
silence this with a custom error handler (I tested it, and it works). But the
part that is confusing to me, as a user of the Python API, is that I did not
ask the API to do anything with int32s. All I did was open the dataset using
the default parameters of gdal.Open(). I would not expect a warning to be
reported in that circumstance, unless opening .img files that use nan as the
NoData value was problematic for GDAL in some way. That is why I was suggesting
that the warning be removed.JasonOn 5/8/25 17:51, Even Rouault wrote:Jason,It
looks like something in the code asks a float64 field to be returned as a
int32, and thus NaN has to be turned into something else. That's perhaps fine
in the context where that happens with your file and could potentially be
silenced, but access to the file would be needed to investigateEvenLe
08/05/2025 à 23:01, Jason Roberts via gdal-dev a écrit :Hi GDAL team,I'm
working with the GDAL Python API. I have some HFA (.img) files that are float32
and that use nan as their NoData value. As far as I can tell, using nan is
allowed but I could be wrong. When I open them, I get "Warning 1: NaN converted
to INT_MAX." Everything seems to work fine after that. Is this message
something I need to worry about? If not, may I suggest you remove it from the
HFA driver if possible?Here's some code demonstrating the message. If need be,
I can provide an example file, or write some code to generate one.>>> import
numpy as np>>> from osgeo import gdal>>> gdal.__version__ # this version
is packaged with ArcGIS Pro 3.4, but I don't think the version
matters'3.9.2e'>>> ds =
gdal.Open(r'\\conch\denmod\Covariates\NARW25\CMEMS_GLORYS\SST\1999\SST_199901.img',
gdal.GA_ReadOnly)Warning 1: NaN converted to INT_MAX.>>> band =
ds.GetRasterBand(1)>>> gdal.GetDataTypeName(band.DataType)'Float32'>>>
band.GetNoDataValue()nan>>> arr = band.ReadAsArray() # the data look ok:>>>
np.isnan(arr).sum()86788>>> (~np.isnan(arr)).sum()142985>>> np.max(arr)nan>>>
np.nanmax(arr)27.078554As far as I can tell, the warning comes from this code
in gdal/frmts/hfa/hfafield.cpp: else if
(std::isnan(dfDoubleRet)) {
CPLError(CE_Warning, CPLE_AppDefined, "NaN
converted to INT_MAX."); nIntRet = nMax; }But
I don't know if there are any negative ramifications that will result.Thank you
for your help. And, as always, thank you very much for developing and
maintaining GDAL.Jason _______________________________________________
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