Merge pull request #73 from geoadmin/develop

New Release v1.8.0 - #minor
geoadmin · May 3, 2023 · 8787456 · 8787456
2 parents 147a098 + a746d43
commit 8787456
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Showing 3 changed files with 15 additions and 3 deletions.
diff --git a/app/helpers/utils.py b/app/helpers/utils.py
@@ -1,5 +1,6 @@
 import hashlib
 import logging
+import math
 import re
 from datetime import datetime
 
@@ -70,7 +71,15 @@ def set_cache_control(headers, restriction):
     return headers
 
 
-def get_closest_zoom(resolution, epsg):
+def resolution_factor_at_latitude(latitude):
+    return math.cos(latitude * (math.pi / 180.0))
+
+
+# Zoom is defined at the Equator for WebMercator, layer defined at the
+# latitude of Switzerland have to be corrected.
+def get_closest_zoom(resolution, epsg, latitude=0.0):
+    if int(epsg) == 3857:
+        resolution /= resolution_factor_at_latitude(latitude)
     tilegrid = getTileGrid(int(epsg))()
     return tilegrid.getClosestZoom(float(resolution))
 

diff --git a/app/templates/Layers.xml.jinja b/app/templates/Layers.xml.jinja
@@ -37,7 +37,7 @@
                 {% endfor %}
             </Dimension>
             <TileMatrixSetLink>
-                <TileMatrixSet>{{ epsg }}_{{ layer.resolution_max|get_closest_zoom(epsg) }}</TileMatrixSet>
+                <TileMatrixSet>{{ epsg }}_{{ layer.resolution_max|get_closest_zoom(epsg, latitude=standard_latitude) }}</TileMatrixSet>
             </TileMatrixSetLink>
             {# ## ATTENTION: s3 tiles have a row/col order, mapproxy ones the standard col/row #}
             {% for format in layer.formats %}

diff --git a/app/views.py b/app/views.py
@@ -18,6 +18,8 @@
 
 logger = logging.getLogger(__name__)
 
+STANDARD_LATITUDE_FOR_SWITZERLAND = 47.0
+
 
 class GetCapabilities(View):
     methods = ['GET']
@@ -107,7 +109,8 @@ def get_context(cls, models, epsg, lang):
             'epsg': epsg,
             'default_tile_matrix_set': get_default_tile_matrix_set(epsg),
             'legend_base_url': app.config["LEGENDS_BASE_URL"],
-            'language': lang
+            'language': lang,
+            'standard_latitude': STANDARD_LATITUDE_FOR_SWITZERLAND
         }
         logger.debug('Data context created in %fs', time.time() - start)
         return context