konova/konova/models/parcel.py

"""
Author: Michel Peltriaux
Organization: Struktur- und Genehmigungsdirektion Nord, Rhineland-Palatinate, Germany
Contact: michel.peltriaux@sgdnord.rlp.de
Created on: 16.12.21

"""
from django.db import models

from konova.models import UuidModel


class AdministrativeSpatialReference(models.Model):
    key = models.CharField(
        max_length=255,
        help_text="Represents Kreisschlüssel",
        null=True,
        blank=True
    )
    name = models.CharField(
        max_length=1000,
        help_text="Kreis",
        null=True,
        blank=True,
    )

    class Meta:
        abstract = True

    def __str__(self):
        return f"{self.name} ({self.key})"

    @property
    def table_str(self):
        return f"{self.name} ({self.key})"


class District(UuidModel, AdministrativeSpatialReference):
    """ The model District refers to "Kreis"

    """

    class Meta:
        constraints = [
            models.UniqueConstraint(
                fields=[
                    "key",
                    "name",
                ],
                name="Unique district constraint"
            )
        ]


class Municipal(UuidModel, AdministrativeSpatialReference):
    """ The model Municipal refers to "Gemeinde"

    """
    district = models.ForeignKey(
        District,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
    )

    class Meta:
        constraints = [
            models.UniqueConstraint(
                fields=[
                    "key",
                    "name",
                    "district",
                ],
                name="Unique municipal constraint"
            )
        ]


class ParcelGroup(UuidModel, AdministrativeSpatialReference):
    """ The model ParcelGroup refers to "Gemarkung", which is defined as a loose group of parcels

    """
    municipal = models.ForeignKey(
        Municipal,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
    )

    class Meta:
        constraints = [
            models.UniqueConstraint(
                fields=[
                    "key",
                    "name",
                    "municipal",
                ],
                name="Unique parcel group constraint"
            )
        ]


class Parcel(UuidModel):
    """ The Parcel model holds administrative data on covered properties.

    Due to the unique but relevant naming of the administrative data, we have to use these namings as field
    names in german. Any try to translate them to English result in strange or insufficient translations.

    All fields have to be CharFields as well, since there are e.g. Flurstücksnummer holding e.g. '123____' which
    can not be realized using numerical fields.

    To avoid conflicts due to german Umlaute, the field names are shortened and vocals are dropped.

    """
    geometries = models.ManyToManyField("konova.Geometry", blank=True, related_name="parcels", through='ParcelIntersection')
    district = models.ForeignKey("konova.District", on_delete=models.SET_NULL, null=True, blank=True, related_name="parcels")
    municipal = models.ForeignKey("konova.Municipal", on_delete=models.SET_NULL, null=True, blank=True, related_name="parcels")
    parcel_group = models.ForeignKey(
        "konova.ParcelGroup",
        on_delete=models.SET_NULL,
        help_text="Gemarkung",
        null=True,
        blank=True,
        related_name="parcels"
    )
    flr = models.IntegerField(
        help_text="Flur",
        null=True,
        blank=True,
    )
    flrstck_nnr = models.IntegerField(
        help_text="Flurstücksnenner",
        null=True,
        blank=True,
    )
    flrstck_zhlr = models.IntegerField(
        help_text="Flurstückszähler",
        null=True,
        blank=True,
    )
    updated_on = models.DateTimeField(auto_now_add=True)

    class Meta:
        constraints = [
            models.UniqueConstraint(
                fields=[
                    "district",
                    "municipal",
                    "parcel_group",
                    "flr",
                    "flrstck_nnr",
                    "flrstck_zhlr",
                ],
                name="Unique parcel constraint"
            )
        ]

    def __str__(self):
        return f"{self.parcel_group} | {self.flr} | {self.flrstck_zhlr} | {self.flrstck_nnr}"


class ParcelIntersection(UuidModel):
    """
    ParcelIntersection is an intermediary model, which is used to add extras to the
    M2M relation between Parcel and Geometry.
    """
    parcel = models.ForeignKey(Parcel, on_delete=models.CASCADE)
    geometry = models.ForeignKey("konova.Geometry", on_delete=models.CASCADE)