[gdal-dev] GetProjection returns empty string, python 3.7
Nicolas Cadieux
njacadieux.gitlab at gmail.com
Mon Oct 26 16:00:55 PDT 2020
Hi,
I am currently on 3.0.2. and the Anaconda Navigator does not give me
higher options. I will create a new clean environments and try conda
install. I will try changing the code I think my version of the code
probably corresponds to <3 versions of gdal. It's a cut and paste from
the gdal tutorial. Can I send you my test file to test on your code?
Thanks, I appreciate the help.
Nicolas
On 2020-10-26 6:31 p.m., Paul Harwood wrote:
> Me too.
>
> But which conda package for gdal are you using - there are a lot of
> ones out there.
>
> Are you using conda install -c conda-forge gdal ?
>
> It should be version 3.1.4 at the moment ?
>
> Also - I don't know if this is part of it but ...
>
> "srs = osr.SpatialReference()
> srs.SetUTM(11, 1)
> srs.SetWellKnownGeogCS("NAD27")
> dst_ds.SetProjection(srs.ExportToWkt())
> "
>
> why not just
>
> "srs = osr.SpatialReference()
> srs.SetUTM(11, 1)
> srs.SetWellKnownGeogCS("NAD27")
> dst_ds.SetSpatialRef(srs)
> "
> ??
>
> On Mon, 26 Oct 2020 at 22:11, Nicolas Cadieux
> <njacadieux.gitlab at gmail.com <mailto:njacadieux.gitlab at gmail.com>> wrote:
>
> Hi,
>
> Comes back as None for me... :( I'am working with Anaconda.
> Could it be my environment?
>
> Nicolas
>
> On 2020-10-26 5:04 p.m., Paul Harwood wrote:
>> GetSpatialRef is OSR based and it is certainly working for me
>> against GDAL Raster datasets - it would not be a method against
>> the GDAL Dataset if it was only an OGR thing - OGR has its own
>> objects.
>>
>> This code is working for me at this very minute and giving me the
>> name of the CRS for a gtiff
>>
>> dataset = gdal.Open(str(filepath))
>> if dataset:
>> proj = "None"
>> crs = dataset.GetSpatialRef()
>> if crs:
>> proj = crs.GetName()
>> return {"type": "gdal", "driver":
>> dataset.GetDriver().ShortName, "proj": proj}
>>
>> On Mon, 26 Oct 2020 at 20:08, Nicolas Cadieux
>> <njacadieux.gitlab at gmail.com
>> <mailto:njacadieux.gitlab at gmail.com>> wrote:
>>
>> Hi,
>>
>> Thanks for helping. I will put my code at the end. The
>> problem seems to be between gdal python lib 2.2.2 and 3.0.2.
>> Under 2.2.2 and < 3, GetProjection() works well but return
>> nothing with gdal python lib 3.0.2. It's my understanding
>> that .GetSpatialRef is for OGR data (vector). Am I wrong?
>>
>> I was using GetProjection() because that is the method used
>> in the raster_api tutorial.
>> (https://gdal.org/tutorials/raster_api_tut.html)
>>
>> I understand that gdal 3 now relies on proj 6 for the
>> SpatialRef. I'am trying to figure out if is a problem with
>> proj or with gdal...
>>
>> Nicolas
>>
>>
>> code:
>>
>> # -*- coding: utf-8 -*-
>> """
>> Created on Sun Oct 25 15:09:05 2020
>>
>> @author: Nicolas
>> """
>> #https://stackoverflow.com/questions/37648439/simplest-way-to-save-array-into-raster-file-in-python
>>
>>
>> from osgeo import gdal, osr, ogr
>> import numpy
>>
>> print (gdal.__version__)
>>
>> # https://gdal.org/tutorials/raster_api_tut.html
>> fileformat = "GTiff"
>> driver = gdal.GetDriverByName(fileformat)
>> metadata = driver.GetMetadata()
>> if metadata.get(gdal.DCAP_CREATE) == "YES":
>> print("Driver {} supports Create()
>> method.".format(fileformat))
>>
>> if metadata.get(gdal.DCAP_CREATECOPY) == "YES":
>> print("Driver {} supports CreateCopy()
>> method.".format(fileformat))
>> dst_ds = driver.Create(r"c:\temp\gdal.tif", xsize=512, ysize=512,
>> bands=1, eType=gdal.GDT_Byte)
>> dst_ds.SetGeoTransform([444720, 30, 0, 3751320, 0, -30])
>> srs = osr.SpatialReference()
>> srs.SetUTM(11, 1)
>> srs.SetWellKnownGeogCS("NAD27")
>> dst_ds.SetProjection(srs.ExportToWkt())
>> print ('srs = ',srs)# this is good
>> raster = numpy.zeros((512, 512), dtype=numpy.uint8)
>> dst_ds.GetRasterBand(1).WriteArray(raster)
>> # Once we're done, close properly the dataset
>> srs = None
>> dst_ds = None #srs is file and well georeferenced in Qgis.
>>
>> #
>> ---------------------------------------------------------------------------
>> # open dataset try to read srs
>> #
>> ---------------------------------------------------------------------------
>> raster_ds = gdal.Open(r"C:\temp\gdal.tif")
>> # first try
>> print("Projection is {}".format(raster_ds.GetProjection()))
>>
>> # second try
>> srs = osr.SpatialReference()
>> srs.ImportFromWkt(raster_ds.GetProjectionRef())
>> print ('srs =', srs)
>> # thrid try
>> srs = osr.SpatialReference()
>> srs = raster_ds.GetProjection()
>> print('srs =', srs)
>> srs = raster_ds.GetProjectionRef()
>> # forth try
>> # from gdal_info
>> https://github.com/OSGeo/gdal/blob/master/gdal/swig/python/samples/gdalinfo.py
>> pszProjection = raster_ds.GetProjectionRef()
>> print(pszProjection)
>> if pszProjection is not None:
>> hSRS = osr.SpatialReference()
>> if hSRS.ImportFromWkt(pszProjection) == gdal.CE_None:
>> pszPrettyWkt = hSRS.ExportToPrettyWkt(False)
>> print("Coordinate System is:\n%s" % pszPrettyWkt)
>> else:
>> print("Coordinate System is `%s'" % pszProjection)
>>
>>
>> On 2020-10-26 3:44 p.m., Paul Harwood wrote:
>>> I am not sure why you are using GetProjection and not
>>> GetSpatialRef ? Although, the code snippet you included in
>>> your email does not seem to use either?
>>>
>>> I certainly was in the process of working on some code that
>>> uses .GeoSptialRef very successfully on GDAL3.1.3 - so I am
>>> sure that it is working!
>>>
>>> On Mon, 26 Oct 2020 at 18:36, Nicolas Cadieux
>>> <njacadieux.gitlab at gmail.com
>>> <mailto:njacadieux.gitlab at gmail.com>> wrote:
>>>
>>> New info!
>>>
>>> GetProjection works with gdal python 2.2.2 and 2.3.3 but
>>> not with with
>>> gdal 3.0.2. Is this a change in the gdal library?
>>>
>>> Nicolas
>>>
>>> On 2020-10-26 1:53 p.m., Nicolas Cadieux wrote:
>>> > Hi,
>>> >
>>> > In case mail question was not clear, I have posted the
>>> questions about
>>> > this on stackexchange. I posted a full code that you
>>> can run exposing
>>> > my problem and question.
>>> >
>>> > Thanks
>>> >
>>> > Nicolas
>>> >
>>> >
>>> https://gis.stackexchange.com/questions/377567/cannot-get-projection-from-raster-dataset-using-getprojection
>>>
>>> >
>>> >
>>> > On 2020-10-25 9:31 p.m., Nicolas Cadieux wrote:
>>> >> Hi,
>>> >>
>>> >> With the following code, I get an empty string
>>> indicating the
>>> >> projection is not valid.
>>> >>
>>> >> from osgeo import gdal, osr
>>> >> raster_ds = gdal.Open(r"C:\temp\180922_WTE3.tif")
>>> >> target_ds =
>>> >>
>>> driver.Create(r"c:\temp\output.tif",xsize=raster_ds_ncol,ysize=raster_ds_nrow,bands
>>>
>>> >> = 1,eType = gdal.GDT_Float32)
>>> >> (array is a numpty array.)
>>> >> raster_srs = osr.SpatialReference()
>>> >> raster_srs.ImportFromWkt(raster_ds.GetProjectionRef())
>>> >> target_ds.SetProjection(raster_srs.ExportToWkt())
>>> >> target_ds.GetRasterBand(1).WriteArray(array)
>>> >> raster_ds = None #close dataset
>>> >> target_ds=None
>>> >>
>>> >> Below is the result of gdal info from qgis. File
>>> appears to have a
>>> >> valid projection and is properly georeferenced in
>>> QGIS using other
>>> >> data sets. Is this projection wrong or am I missing
>>> something in my
>>> >> python code? The goal is to extract the projection
>>> from raster_ds
>>> >> set in order to apply to target_ds. I can create the
>>> file, apply a
>>> >> geotransform but can't get the projection. Can you help?
>>> >>
>>> >> Thanks/merci!
>>> >>
>>> >> Nicolas
>>> >>
>>> >> QGIS version: 3.14.16-Pi
>>> >> QGIS code revision: df27394552
>>> >> Qt version: 5.11.2
>>> >> GDAL version: 3.0.4
>>> >> GEOS version: 3.8.1-CAPI-1.13.3
>>> >> PROJ version: Rel. 6.3.2, May 1st, 2020
>>> >> Processing algorithm…
>>> >> Algorithm 'Raster information' starting…
>>> >> Input parameters:
>>> >> { 'EXTRA' : '', 'INPUT' : 'C:/temp/180922_WTE3.tif',
>>> 'MIN_MAX' :
>>> >> False, 'NOGCP' : False, 'NO_METADATA' : False,
>>> 'OUTPUT' :
>>> >> 'TEMPORARY_OUTPUT', 'STATS' : False }
>>> >>
>>> >> GDAL command:
>>> >> gdalinfo C:/temp/180922_WTE3.tif
>>> >> GDAL command output:
>>> >> Warning 1: TIFFReadDirectory:Sum of Photometric
>>> type-related color
>>> >> channels and ExtraSamples doesn't match
>>> SamplesPerPixel. Defining
>>> >> non-color channels as ExtraSamples.
>>> >>
>>> >> Driver: GTiff/GeoTIFF
>>> >> Files: C:/temp/180922_WTE3.tif
>>> >> Size is 1194, 2783
>>> >> Coordinate System is:
>>> >> PROJCRS["WGS 84 / UTM zone 18N",
>>> >> BASEGEOGCRS["WGS 84",
>>> >> DATUM["World Geodetic System 1984",
>>> >> ELLIPSOID["WGS 84",6378137,298.257223563,
>>> >> LENGTHUNIT["metre",1]]],
>>> >> PRIMEM["Greenwich",0,
>>> >> ANGLEUNIT["degree",0.0174532925199433]],
>>> >> ID["EPSG",4326]],
>>> >> CONVERSION["UTM zone 18N",
>>> >> METHOD["Transverse Mercator",
>>> >> ID["EPSG",9807]],
>>> >> PARAMETER["Latitude of natural origin",0,
>>> >> ANGLEUNIT["degree",0.0174532925199433],
>>> >> ID["EPSG",8801]],
>>> >> PARAMETER["Longitude of natural origin",-75,
>>> >> ANGLEUNIT["degree",0.0174532925199433],
>>> >> ID["EPSG",8802]],
>>> >> PARAMETER["Scale factor at natural origin",0.9996,
>>> >> SCALEUNIT["unity",1],
>>> >> ID["EPSG",8805]],
>>> >> PARAMETER["False easting",500000,
>>> >> LENGTHUNIT["metre",1],
>>> >> ID["EPSG",8806]],
>>> >> PARAMETER["False northing",0,
>>> >> LENGTHUNIT["metre",1],
>>> >> ID["EPSG",8807]]],
>>> >> CS[Cartesian,2],
>>> >> AXIS["(E)",east,
>>> >> ORDER[1],
>>> >> LENGTHUNIT["metre",1]],
>>> >> AXIS["(N)",north,
>>> >> ORDER[2],
>>> >> LENGTHUNIT["metre",1]],
>>> >> USAGE[
>>> >> SCOPE["unknown"],
>>> >> AREA["World - N hemisphere - 78°W to 72°W - by country"],
>>> >> BBOX[0,-78,84,-72]],
>>> >> ID["EPSG",32618]]
>>> >> Data axis to CRS axis mapping: 1,2
>>> >> Origin = (459417.200000000011642,5028584.700000000186265)
>>> >> Pixel Size = (0.050000000000000,-0.050000000000000)
>>> >> Metadata:
>>> >> AREA_OR_POINT=Area
>>> >> TIFFTAG_XRESOLUTION=1
>>> >> TIFFTAG_YRESOLUTION=1
>>> >> Image Structure Metadata:
>>> >> INTERLEAVE=BAND
>>> >> Corner Coordinates:
>>> >> Upper Left ( 459417.200, 5028584.700) ( 75d31'
>>> 7.03"W, 45d24'34.58"N)
>>> >> Lower Left ( 459417.200, 5028445.550) ( 75d31'
>>> 6.99"W, 45d24'30.07"N)
>>> >> Upper Right ( 459476.900, 5028584.700) ( 75d31'
>>> 4.28"W, 45d24'34.59"N)
>>> >> Lower Right ( 459476.900, 5028445.550) ( 75d31'
>>> 4.24"W, 45d24'30.08"N)
>>> >> Center ( 459447.050, 5028515.125) ( 75d31' 5.63"W,
>>> 45d24'32.33"N)
>>> >> Band 1 Block=1194x1 Type=UInt16, ColorInterp=Red
>>> >> ...
>>> >> Band 288 Block=1194x1 Type=UInt16, ColorInterp=Undefined
>>> >>
>>> >>
>>> >>
>>> _______________________________________________
>>> gdal-dev mailing list
>>> gdal-dev at lists.osgeo.org <mailto:gdal-dev at lists.osgeo.org>
>>> https://lists.osgeo.org/mailman/listinfo/gdal-dev
>>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20201026/742f27ee/attachment-0001.html>
More information about the gdal-dev
mailing list