templatetags: add |reproj to transform lon/lat to given map projection (#34966)

tests/test_templates.py

@@ -6,6 +6,7 @@ import string
 
 from django.test import override_settings
 from quixote import cleanup
+from qommon.substitution import CompatibilityNamesDict
 from qommon.template import Template, TemplateError
 from wcs.conditions import Condition
 from wcs.variables import LazyFormData
@@ -511,3 +512,13 @@ def test_get_filter():
 
     tmpl = Template('{{ foo|get:0 }}')
     assert tmpl.render({'foo': ['bar', 'baz']}) == 'bar'
+
+def test_reproj():
+
+    class MockFormData(object):
+        formdef = None
+        geolocations = {'base': {'lat': 48, 'lon': 2}}
+
+    lazy_formdata = LazyFormData(MockFormData())
+    tmpl = Template('{% with form_geoloc_base|reproj:"EPSG:3946" as c %}{{c.0}}/{{c.1}}{% endwith %}')
+    assert tmpl.render(CompatibilityNamesDict({'form': lazy_formdata})) == '1625337.15483/5422836.71627'

wcs/qommon/templatetags/qommon.py

@@ -23,6 +23,7 @@ import math
 import string
 import random
 
+import pyproj
 from pyproj import Geod
 
 from django import template
@@ -341,3 +342,9 @@ def distance_filter(queryset, distance=1000):
 @register.filter
 def order_by(queryset, attribute):
     return queryset.order_by(attribute)
+
+@register.filter
+def reproj(coords, projection_name):
+    proj = pyproj.Proj(init='EPSG:4326')
+    target_proj = pyproj.Proj(init=projection_name)
+    return pyproj.transform(proj, target_proj, coords['lon'], coords['lat'])