How can I acess Multilinestring(dim=3)

[Richard Mair]

Hi i am using

geom = models.MultiLineStringField(

dim=3, srid=EPSG_CODE, blank=True, null=True, spatial_index=True

) # EPSG:3128=AustriaLambert

and my PostGIS-DB is using (MultilinestringM

ALTER TABLE IF EXISTS public."KMSYS"
    ADD COLUMN geom geometry(MultiLineStringM,31287);

but when I access my Model I only get 2 dimensional response

Can anybody lead me to the correct handling

[David James Nwoyie]

Increase the dim to 4 because of the Django of use 0 as the starting point 

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[Richard Mair]

Hi David,

thanks for your help. I tried setting dim to 4 but did't see any change.

Here is my model:

```python

from django.contrib.gis.db import models

class Kmsys(models.Model):

# Define constants ----------------------------

EPSG_CODE = 31287

NAME_OF_GEOMETRY_FIELD = "geom"

# F I E L D S -------------------------------------------------

id = models.IntegerField(primary_key=True)

geom = models.MultiLineStringField(

dim=4, srid=EPSG_CODE, blank=True, null=True, spatial_index=True

) # EPSG:31287=AustriaLambert

object_id = models.BigIntegerField(db_column="OBJECTID", unique=True)

code = models.CharField(max_length=80, db_column="KMSYS_CODE", unique=False)

name = models.CharField(max_length=500, db_column="KMSYS_BEZEICHNUNG", unique=False)

start_date = models.DateTimeField(db_column="KMSYS_START_DATUM")

end_date = models.DateTimeField(db_column="KMSYS_ENDE_DATUM")

len = models.FloatField(db_column="LEN")

km_from = models.FloatField(db_column="KMSYS_KMVON")

km_till = models.FloatField(db_column="KMSYS_KMBIS")

parts_quantity = models.IntegerField(db_column="TEILE_ANZ")

fme_date = models.DateTimeField(db_column="FME_DATUM")

se_anno_cad_data = models.FileField(db_column="SE_ANNO_CAD_DATA")

bauk_id = models.FloatField(db_column="BAUK_ID")

# Meta-Class ------------------------------------------------------

class Meta:

managed = False

db_table = "KMSYS"

# db_table = '"public"."KMSYS"'

verbose_name = "Kmsys"

verbose_name_plural = "Kmsys"

ordering = ["code"]

# Methods ---------------------------------------------------------

def __str__(self) -> str:

"""String for representing the Model object."""

return f"{self.code} | {self.name} | {self.start_date} | {self.end_date} | {self.km_from} | {self.km_till} | {self.parts_quantity} | {self.fme_date} | {self.se_anno_cad_data} | {self.bauk_id}"

```

And this is the pytest that keeps failing -> At the beginning i just tested the dim=3 manually without db-access

from django.contrib.gis.geos import GEOSGeometry, LineString, MultiLineString, Point

from rest_framework.reverse import reverse

import logging

import pytest

from kmsys.models import Kmsys

from kmsys.test.test_runner import DjangoNoCreateAndDropRunner

logger = logging.getLogger(__name__)

# use pytest marks to tell pytest-django your test needs database access! In case only a certain method needs db-access use @pytest.mark.django_db as decorator of the according test-method.

pytestmark = pytest.mark.django_db

class TestModel:

"""

Test suite for KMSYS

"""

def test_query_kmsys(self):

"""

Test whether the kmsys can be accessed.

"""

# ARRANGE -------------

# simple dimension test with GDAL

# p: OGRGeometry = OGRGeometry("Point (1 2 3 )")

# assert p.coord_dim == 3

# simple dimension test with GEOS

p: GEOSGeometry = GEOSGeometry("Point (1 2 3 )")

assert p.hasz

# simple dimension test with GEOS Multilinestring

ls1 = LineString([(0, 0, 150), (1, 1, 151)], srid="31287")

ls2 = LineString([(2, 2, 153), (3, 3, 154)], srid="31287")

mls = MultiLineString(ls1, ls2)

assert mls.hasz

# ACT -----------------

first_kmsys: Kmsys = Kmsys.objects.all().first()

logger.info(f"first: {first_kmsys}")

# ASSERT -----------------

assert first_kmsys.geom.hasz

assert len(first_kmsys.geom.coords[0][0]) == 3

assert len(Kmsys.objects.all()) == 388

regards Richard