Re: [postgis-users] PL/Python

[David Haynes]

Hello Remi,

Do you know who, what list I should report this to? In my work I found is
that plpython doesn't work well with the memory drivers for gdal or ogr.
Specifically when I would run the my code it might create the raster
dataset in memory and the for no apparent reason it would terminate the
database connection. I thought this was specific to gdal memory until I
encountered some downstream issues with vector datasets.

The error was resolved choosing actual directories and writing the data
there. I suppose that there would have to a specific plpython memory driver.



On Sat, May 21, 2016 at 5:04 AM, Rémi Cura  wrote:

> Hey,
> debuggin plpython is a bit of a pain.
> Maybe you are aware that you can use
> plpy.notice to print values during execution.
>
> This blog
> 
> seems to indicate that what you do should work:
>
> driver = gdal.GetDriverByName( 'MEM' )
> ds = driver.Create( '', 255, 255, 1, gdal.GDT_Int32)
>
>
> Maybe you can check that executing that in plain python while logged as 
> postgres works?
>
> Cheers,
> Rémi-C
>
>
>
>
>
> 2016-05-18 21:26 GMT+02:00 David Haynes :
>
>> Yes because the second function in my doesn't error.
>>
>> On Wed, May 18, 2016 at 12:06 PM, Martijn Meijers > > wrote:
>>
>>> I think the gdal.getDriver call returns None. Hence the attribute error
>>> on the line afterwards. Are you sure that 19 is what you should pass as
>>> input?
>>>
>>> Martijn
>>>
>>> Verzonden vanaf mobiel.
>>>
>>>
>>>  Oorspronkelijk bericht 
>>> Van: David Haynes
>>> Datum:18-05-2016 17:35 (GMT+01:00)
>>> Aan: postgis-users@lists.osgeo.org
>>> Onderwerp: [postgis-users] PL/Python
>>>
>>> Hello,
>>>
>>> I have a question regarding importing the gdal library using pl/python.
>>> Specifically, I want to create an in memory raster using the gdal library.
>>> This is a snippet of code that I have written,
>>>
>>> CREATE OR REPLACE FUNCTION terrapop_area_level_to_raster2(
>>> sample_geog_level_id bigint, raster_variable_id bigint, raster_band bigint)
>>> RETURNS text AS
>>> $BODY$
>>> from osgeo import gdal
>>> import numpy as np
>>> from osgeo import ogr, osr
>>>
>>> memDriver = gdal.GetDriver(19)
>>> #memDriver = gdal.GetDriverByName('MEM')
>>> memRast = memDriver.Create('', 10, 10, 1, gdal.GDT_Int32)
>>>
>>> This is the error I receive. A python NoneType error. Which seems to
>>> that the gdal class has not been imported. I have verified that gdal is
>>> available on the system.
>>>
>>> ERROR: AttributeError: 'NoneType' object has no attribute 'Create'
>>> SQL state: XX000
>>>
>>> However, this function on the same server and database returns to me all
>>> the gdal drivers. Any idea how I can diagnose this problem?
>>>
>>> CREATE OR REPLACE FUNCTION gdal_drivers()
>>>   RETURNS SETOF text AS
>>> $BODY$
>>>
>>> from osgeo import gdal
>>> driver = gdal.GetDriverByName('MEM')
>>> rast = driver.Create('', 2, 4, 1, gdal.GDT_Int32)
>>>
>>> names = []
>>> driverall = gdal.GetDriverCount()
>>> for i in range(gdal.GetDriverCount()):
>>> driver = gdal.GetDriver(i)
>>> drivername = driver.ShortName
>>> names.append([i,drivername])
>>>
>>> return names
>>>
>>> $BODY$
>>>   LANGUAGE plpythonu VOLATILE
>>>
>>>
>>>
>>>
>>>
>>>
>>> ___
>>> postgis-users mailing list
>>> postgis-users@lists.osgeo.org
>>> http://lists.osgeo.org/mailman/listinfo/postgis-users
>>>
>>
>>
>> ___
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>
>
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Re: [postgis-users] PL/Python

[Rémi Cura]

Hey,
debuggin plpython is a bit of a pain.
Maybe you are aware that you can use
plpy.notice to print values during execution.

This blog

seems to indicate that what you do should work:

driver = gdal.GetDriverByName( 'MEM' )
ds = driver.Create( '', 255, 255, 1, gdal.GDT_Int32)


Maybe you can check that executing that in plain python while logged
as postgres works?

Cheers,
Rémi-C





2016-05-18 21:26 GMT+02:00 David Haynes :

> Yes because the second function in my doesn't error.
>
> On Wed, May 18, 2016 at 12:06 PM, Martijn Meijers 
> wrote:
>
>> I think the gdal.getDriver call returns None. Hence the attribute error
>> on the line afterwards. Are you sure that 19 is what you should pass as
>> input?
>>
>> Martijn
>>
>> Verzonden vanaf mobiel.
>>
>>
>>  Oorspronkelijk bericht 
>> Van: David Haynes
>> Datum:18-05-2016 17:35 (GMT+01:00)
>> Aan: postgis-users@lists.osgeo.org
>> Onderwerp: [postgis-users] PL/Python
>>
>> Hello,
>>
>> I have a question regarding importing the gdal library using pl/python.
>> Specifically, I want to create an in memory raster using the gdal library.
>> This is a snippet of code that I have written,
>>
>> CREATE OR REPLACE FUNCTION terrapop_area_level_to_raster2(
>> sample_geog_level_id bigint, raster_variable_id bigint, raster_band bigint)
>> RETURNS text AS
>> $BODY$
>> from osgeo import gdal
>> import numpy as np
>> from osgeo import ogr, osr
>>
>> memDriver = gdal.GetDriver(19)
>> #memDriver = gdal.GetDriverByName('MEM')
>> memRast = memDriver.Create('', 10, 10, 1, gdal.GDT_Int32)
>>
>> This is the error I receive. A python NoneType error. Which seems to that
>> the gdal class has not been imported. I have verified that gdal is
>> available on the system.
>>
>> ERROR: AttributeError: 'NoneType' object has no attribute 'Create'
>> SQL state: XX000
>>
>> However, this function on the same server and database returns to me all
>> the gdal drivers. Any idea how I can diagnose this problem?
>>
>> CREATE OR REPLACE FUNCTION gdal_drivers()
>>   RETURNS SETOF text AS
>> $BODY$
>>
>> from osgeo import gdal
>> driver = gdal.GetDriverByName('MEM')
>> rast = driver.Create('', 2, 4, 1, gdal.GDT_Int32)
>>
>> names = []
>> driverall = gdal.GetDriverCount()
>> for i in range(gdal.GetDriverCount()):
>> driver = gdal.GetDriver(i)
>> drivername = driver.ShortName
>> names.append([i,drivername])
>>
>> return names
>>
>> $BODY$
>>   LANGUAGE plpythonu VOLATILE
>>
>>
>>
>>
>>
>>
>> ___
>> postgis-users mailing list
>> postgis-users@lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/postgis-users
>>
>
>
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Re: [postgis-users] PL/Python

[Martijn Meijers]

I think the gdal.getDriver call returns None. Hence the attribute error on the 
line afterwards. Are you sure that 19 is what you should pass as input?

Martijn

Verzonden vanaf mobiel.

 Oorspronkelijk bericht Van: David Haynes 
 Datum:18-05-2016  17:35  (GMT+01:00) 
Aan: postgis-users@lists.osgeo.org Onderwerp: 
[postgis-users] PL/Python 
Hello,

I have a question regarding importing the gdal library using pl/python. 
Specifically, I want to create an in memory raster using the gdal library. This 
is a snippet of code that I have written,

CREATE OR REPLACE FUNCTION terrapop_area_level_to_raster2( sample_geog_level_id 
bigint, raster_variable_id bigint, raster_band bigint) RETURNS text AS
$BODY$   

from osgeo import gdal
import numpy as np
from osgeo import ogr, osr


memDriver = gdal.GetDriver(19)
#memDriver = gdal.GetDriverByName('MEM')
memRast = memDriver.Create('', 10, 10, 1, gdal.GDT_Int32)

This is the error I receive. A python NoneType error. Which seems to that the 
gdal class has not been imported. I have verified that gdal is available on the 
system. 

ERROR: AttributeError: 'NoneType' object has no attribute 'Create'
SQL state: XX000

However, this function on the same server and database returns to me all the 
gdal drivers. Any idea how I can diagnose this problem?

CREATE OR REPLACE FUNCTION gdal_drivers()
  RETURNS SETOF text AS
$BODY$

from osgeo import gdal
driver = gdal.GetDriverByName('MEM')
rast = driver.Create('', 2, 4, 1, gdal.GDT_Int32)

names = []
driverall = gdal.GetDriverCount()
for i in range(gdal.GetDriverCount()):
driver = gdal.GetDriver(i)
drivername = driver.ShortName
names.append([i,drivername])

return names

$BODY$
  LANGUAGE plpythonu VOLATILE





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