GeoDjango / GDAL : Wrong data field being stored

Question

I've been using GeoDjango for a few months now without any issues however when importing a new shape file the id number is being saved instead of the gridcode. The gridcode field has an int that is valuable to my project.

I know the gridcode field is present in the shapefile because I can test it in the shell.

#shell
>>> print(lyr.fields)
['Id', 'gridcode']
>>> feat = lyr[234]
>>> print(feat.get('gridcode'))
90 #This is the desired value

Ive set up my model the same way I always do:

#models.py
class GeoModel(models.Model):
    idn = geomodels.BigIntegerField(null=True)
    grd = geomodels.BigIntegerField(null=True)
    geo = geomodels.MultiPolygonField(null=True, srid=4326)

    def __int__(self):
        return self.grd

path_shp = os.path.abspath(os.path.join(os.path.dirname(app.__file__), 'data', 'folder', 'map.shp'))

mapping = {
    'idn': 'Id',
    'grd': 'gridcode',
    'geo': 'MULTIPOLYGON',}

def run(verbose=True):
    lm = LayerMapping(GeoModel, path_shp, mapping, transform=False)  
    lm.save(strict=True, verbose=verbose)

However when I try to store the data it stores the id number instead of the gridcode. For example, the terminal looks like this:

Saved: GeoModel object (1517)
Saved: GeoModel object (1518)
Saved: GeoModel object (1519)
Saved: GeoModel object (1520)
[ . . .]

Any help would be much appreciated

is the gridcode not being saved at all or is it that it is just not displaying when you save it? You may just need to set the __str__ method on your model — leelum1, Aug 05 '20 at 14:30
I don't think its being saved at all, I haven't been able to pull any value other than the value saved as "self" for each of my Geodjango functions. I tried changing _int_ to str in the self definition and it unsurprisingly gave me a type error : TypeError: __str__ returned non-string (type int). @leelum1 — Display name, Aug 05 '20 at 22:42

Display name · Accepted Answer · 2020-08-30T23:34:32.997

I found a simple workaround. After digging around in the GeoDjango docs under "Lazy Geometries", I found I can just query values that aren't returned by "intersects". For example: When I run

>>> q = GeoModel.objects.get(geo__intersects=point)
# and then I get a value I don't care for (i.e GeoModel object (1520))
# I can then run the following:
>>> q.grd
# and return the following:
90

Although this doesn't directly solve the problem above, it makes the problem irrelevant to me and likely to anyone else facing the same problem in the future.

GeoDjango / GDAL : Wrong data field being stored

1 Answers1