Add area of use and bounding box to CRS info

Closes #18

tests/test_api.py

@@ -1,5 +1,6 @@
 import sys
 import json
+import pprint
 
 import pytest
 
@@ -22,7 +23,9 @@ def _assert_result(entry, expected_json_output):
     """
     print(entry)
     decoded_response = _get_and_decode_response(entry)
-    print(decoded_response)
+    pprint.pprint(decoded_response)
+    print("-----")
+    pprint.pprint(expected_json_output)
     assert decoded_response == expected_json_output
 
 
@@ -315,6 +318,8 @@ def test_crs_return_srid(api_from_v1_1):
             "v4": None,
             "v4_short": None,
             "srid": "EPSG:25832",
+            "area_of_use": "Europe between 6°E and 12°E: Austria; Belgium; Denmark - onshore and offshore; Germany - onshore and offshore; Norway including - onshore and offshore; Spain - offshore.",
+            "bounding_box": [6.0, 38.76, 12.0, 84.33],
         },
         "EPSG:23032+5733": {
             "country": "DK",
@@ -329,6 +334,8 @@ def test_crs_return_srid(api_from_v1_1):
             "v4": None,
             "v4_short": None,
             "srid": "EPSG:23032+5733",
+            "area_of_use": "Denmark - onshore.",
+            "bounding_box": [8.0, 54.51, 15.24, 57.8],
         },
         "DK:S34S": {
             "country": "DK",
@@ -343,6 +350,8 @@ def test_crs_return_srid(api_from_v1_1):
             "v4": None,
             "v4_short": None,
             "srid": "DK:S34S",
+            "area_of_use": "Denmark - Sealand onshore",
+            "bounding_box": [11.0, 54.5, 12.8, 56.5],
         },
     }
 

webproj/api.py

@@ -1,10 +1,11 @@
+from cmath import inf
 import os
 import json
 from pathlib import Path
 
 from flask import Flask
 from flask_cors import CORS
-from flask_restx import Api, Resource, fields, abort
+from flask_restx import Api, Resource, abort
 import pyproj
 from pyproj.transformer import Transformer, AreaOfInterest
 
@@ -207,11 +208,41 @@ def get(self, crs):
         """
         Retrieve information about a given coordinate reference system
 
-        Version 1.1 includes the SRID in the CRS info.
+        Version 1.1 includes the SRID, area of use and bounding box in
+        the CRS info.
         """
 
         output = super().get(crs)
         output["srid"] = crs
+
+        # determine area of use and bounding box
+        try:
+            crs_from_db = pyproj.CRS.from_user_input(crs.upper())
+            if crs_from_db.is_compound:
+                area = inf
+                for subcrs in crs_from_db.sub_crs_list:
+                    aou = subcrs.area_of_use
+                    bbox_area = aou.east - aou.west * aou.north - aou.south
+                    if bbox_area < area:
+                        output["area_of_use"] = subcrs.area_of_use.name
+                        output["bounding_box"] = list(subcrs.area_of_use.bounds)
+            else:
+                output["area_of_use"] = crs_from_db.area_of_use.name
+                output["bounding_box"] = list(crs_from_db.area_of_use.bounds)
+        except pyproj.exceptions.CRSError:
+            # special cases not in proj.db
+            if crs == "DK:S34J":
+                output["area_of_use"] = "Denmark - Jutland onshore"
+                output["bounding_box"] = [8.0, 54.5, 11.0, 57.75]
+            elif crs == "DK:S34S":
+                output["area_of_use"] = "Denmark - Sealand onshore"
+                output["bounding_box"] = [11.0, 54.5, 12.8, 56.5]
+            elif crs == "DK:S45B":
+                output["area_of_use"] = "Denmark - Bornholm onshore"
+                output["bounding_box"] = [14.6, 54.9, 15.2, 55.3]
+            else:
+                abort(404, message=f"'{crs}' not available")
+
         return output