Opened 2 years ago
Closed 2 years ago
#33694 closed Cleanup/optimization (invalid)
GeoDjango tutorial documentation error.
Reported by: | Maxim Danilov | Owned by: | nobody |
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Component: | GIS | Version: | 4.0 |
Severity: | Normal | Keywords: | geodjango, django.contrib.gis |
Cc: | Triage Stage: | Unreviewed | |
Has patch: | no | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | no |
Easy pickings: | no | UI/UX: | no |
Description
I try to follow GeoDjango tutorial.
World Borders step.
https://docs.djangoproject.com/en/4.0/ref/contrib/gis/tutorial/#worldborders
from this sentence:
The world borders data is available in this zip file. Create a data directory in the world application, download the world borders data, and unzip.
i download zip, https://thematicmapping.org/downloads/TM_WORLD_BORDERS-0.3.zip
On the step Defining a Geographic Model:
I create class:
class WorldBorder(models.Model): # GeoDjango-specific: a geometry field (MultiPolygonField) mpoly = models.MultiPolygonField()
i think this is wrong in documentation.
Why i think so:
on the step gdal-interface
https://docs.djangoproject.com/en/4.0/ref/contrib/gis/tutorial/#gdal-interface
we don't have any field/attribute in layer object, but we have attribute "geom"
on the step layermapping
https://docs.djangoproject.com/en/4.0/ref/contrib/gis/tutorial/#layermapping
we have:
world_mapping = { ... 'mpoly' : 'MULTIPOLYGON', }
i think this is wrong in documentation.
Why i think so:
at the same step, on the
layermapping.save(strict=True, verbose=verbose)
We resieve the error:
An error occurred in the current transaction. You can't execute queries until the end of the 'atomic' block. Failed to save {... 'geom': 'MULTIPOLYGON(....)'}
And at the end:
on the step Try ogrinspect
https://docs.djangoproject.com/en/4.0/ref/contrib/gis/tutorial/#try-ogrinspect
we reсeive a normal model with mapping:
class WorldBorder(models.Model): ... geom = models.MultiPolygonField(srid=4326) worldborders_mapping = { ... 'geom' : 'MULTIPOLYGON', }
That's why i think, those parts of GeoDjango tutorial documentation is wrong:
step layermapping,
step Defining a Geographic Model
and, the same error we have also on the page LayerMapping data import utility.
https://docs.djangoproject.com/en/4.0/ref/contrib/gis/layermapping/
there we defined:
class TestGeo(models.Model): ... poly = models.PolygonField(srid=4269) # we want our model in a different SRID mapping = {'name' : 'str', # The 'name' model field maps to the 'str' layer field. 'poly' : 'POLYGON', # For geometry fields use OGC name. } # The mapping is a dictionary
if i use the same TM_WORLD_BORDERS-0.3.shp as a test_poly.shp
it is not works on the:
layermapping.save(verbose=True) # Save the layermap, imports the data.
with the same error.
From the 'Spatial queries' step, the author of the tutorial again uses the 'mpoly' field.
I think the field name "mpoly" was wrong to begin with, but it doesn't matter to Django what I think, does it?
Change History (2)
comment:1 by , 2 years ago
Keywords: | django.contrib.gis added; django.contrib.geo removed |
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comment:2 by , 2 years ago
Easy pickings: | unset |
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Resolution: | → invalid |
Status: | new → closed |
Thanks for this report, however GeoDjango Tutorial works perfectly fine for me, a field name is not important because we defined
world_mapping
. Closing per TicketClosingReasons/UseSupportChannels