Merge pull request #1395 from open-zaak/issue/1060-admin-map-widget

show map in the admin for Zaak.zaakgeometrie

src/openzaak/components/zaken/admin/zaken.py

@@ -2,9 +2,11 @@
 # Copyright (C) 2019 - 2022 Dimpact
 from django import forms
 from django.contrib import admin
+from django.contrib.gis.admin import OSMGeoAdmin
 from django.db.models import CharField, F
 from django.db.models.functions import Concat
 
+from openzaak.forms.widgets import AuthorityAxisOrderOLWidget
 from openzaak.utils.admin import (
     AuditTrailAdminMixin,
     EditInlineAdminMixin,
@@ -599,7 +601,7 @@ def clean(self):
 
 @admin.register(Zaak)
 class ZaakAdmin(
-    AuditTrailAdminMixin, ListObjectActionsAdminMixin, UUIDAdminMixin, admin.ModelAdmin
+    AuditTrailAdminMixin, ListObjectActionsAdminMixin, UUIDAdminMixin, OSMGeoAdmin
 ):
     list_display = (
         "identificatie",
@@ -634,6 +636,7 @@ class ZaakAdmin(
     ]
     raw_id_fields = ("_zaaktype", "hoofdzaak", "_zaaktype_base_url")
     viewset = "openzaak.components.zaken.api.viewsets.ZaakViewSet"
+    widget = AuthorityAxisOrderOLWidget
 
     def get_object_actions(self, obj):
         return (

src/openzaak/forms/widgets.py

@@ -3,6 +3,9 @@
 from typing import Optional, Union
 
 from django import forms
+from django.contrib.gis.admin.widgets import OpenLayersWidget
+from django.contrib.gis.gdal import AxisOrder, OGRGeometry, SpatialReference
+from django.contrib.gis.geos import GEOSGeometry
 from django.utils.translation import ugettext_lazy as _
 
 from dateutil.relativedelta import relativedelta
@@ -141,3 +144,54 @@ def _build_subwidget_context(
             name=f"{name}_{attribute}", value=value, attrs=attrs,
         )
         return widget_context["widget"]
+
+
+class AuthoritySpatialReference(SpatialReference):
+    def __init__(self, srs_input="", srs_type="user"):
+        super().__init__(srs_input, srs_type, axis_order=AxisOrder.AUTHORITY)
+
+
+class AuthorityAxisOrderOLWidget(OpenLayersWidget):
+    """
+    Here is a long and painful explanation why we need it. Buckle up.
+
+    First, `Zaak.zaakgeometry` field is geometric field, not geographic. If it's a point, it has x and y coordinates.
+    But how do we map them to lat and lon? What is the order - lat/lon or lon/lat?
+    Well, there is no consensus what should be the order.
+
+    OpenZaak supports only "ESPG:4326" coordinate system. According to "ESPG:4326" it should be lat/lon order.
+    GDAL<3.0 expects lon/lat order and treat all points like lon/lat.
+    Good news, that GDAL>=3.0 can use the order defined in CRS. And in Open Zaak we support GDAL >= 3.0
+
+    BUT django.contrib.gis.gdal uses traditional axis order (lon/lat) as a default one and user can set up only
+    SRID without axis order when initializing geometry objects.
+
+    OpenStreetMap supports "ESPG:3587" coordinate system. So in the parent class "ESPG:4326" coordinates are
+    transformed to "ESPG:3587" using GDAL api with traditional axis order, where 'x' is treated as 'lon'
+    and 'y' is treated as 'lat'
+
+    In this class we transform coordinates with "Authority" order, for "ESPG:4326" it's lat/lon.
+
+    If in next django versions "axis_order" is treated with more attention, this workaround should be removed.
+    This workaround won't work if os GDAL<3.0. Perhaps, in this case we can use django-leaflet?
+
+    GDAL related doc - https://gdal.org/tutorials/osr_api_tut.html#crs-and-axis-order
+    """
+
+    data_srid = 4326
+
+    def get_context(self, name, value, attrs):
+        if value:
+            ogr = OGRGeometry(value.wkt, AuthoritySpatialReference(value.srid))
+            # ogr = value.ogr
+            ogr.transform(self.params["srid"])
+            value = GEOSGeometry(ogr._geos_ptr(), srid=ogr.srid)
+
+        return super().get_context(name, value, attrs)
+
+    def deserialize(self, value):
+        value = GEOSGeometry(value)
+
+        if value.srid and value.srid != self.data_srid:
+            value.transform(AuthoritySpatialReference(self.data_srid))
+        return value