Valid EDR cube queries for data with decreasing coordinates (#1402)

* resolving case when lat dimensions are decreasing

CF conventions state only that a "coordinate variable must have values that are strictly monotonic (increasing or decreasing)." In the case of PRISM, the lat coordinates are decreasing. pygeoapi failed due to the lat dimension being empty with existing implementation; this update addresses the issue.

* remove blank space

* resolving case when lat dimensions are decreasing

CF conventions state only that a "coordinate variable must have values that are strictly monotonic (increasing or decreasing)." In the case of PRISM, the lat coordinates are decreasing. pygeoapi failed due to the lat dimension being empty with existing implementation; this update addresses the issue.

* remove blank space

* test decreasing latitude

The new test will now uncover if you can successfully serve data stored on S3 AND test if you can perform a cube query on data with monotonically decreasing latitude coordinates at the same time.

* flake8 py3 fixes

pygeoapi/provider/xarray_edr.py

@@ -33,7 +33,11 @@ import numpy as np
 
 from pygeoapi.provider.base import ProviderNoDataError, ProviderQueryError
 from pygeoapi.provider.base_edr import BaseEDRProvider
-from pygeoapi.provider.xarray_ import _to_datetime_string, XarrayProvider
+from pygeoapi.provider.xarray_ import (
+    _to_datetime_string,
+    _convert_float32_to_float64,
+    XarrayProvider,
+)
 
 LOGGER = logging.getLogger(__name__)
 
@@ -180,9 +184,11 @@ class XarrayEDRProvider(BaseEDRProvider, XarrayProvider):
         LOGGER.debug(f"Query type: {kwargs.get('query_type')}")
 
         bbox = kwargs.get('bbox')
+        xmin, ymin, xmax, ymax = self._configure_bbox(bbox)
+
         if len(bbox) == 4:
-            query_params[self.x_field] = slice(bbox[0], bbox[2])
+            query_params[self.x_field] = slice(bbox[xmin], bbox[xmax])
-            query_params[self.y_field] = slice(bbox[1], bbox[3])
+            query_params[self.y_field] = slice(bbox[ymin], bbox[ymax])
         else:
             raise ProviderQueryError('z-axis not supported')
 
@@ -206,6 +212,7 @@ class XarrayEDRProvider(BaseEDRProvider, XarrayProvider):
             else:
                 data = self._data
             data = data.sel(query_params)
+            data = _convert_float32_to_float64(data)
         except KeyError:
             raise ProviderNoDataError()
 
@@ -288,3 +295,11 @@ class XarrayEDRProvider(BaseEDRProvider, XarrayProvider):
         except KeyError:
             time_steps = kwargs.get('limit')
         return time, time_steps
+
+    def _configure_bbox(self, bbox):
+        xmin, ymin, xmax, ymax = 0, 1, 2, 3
+        if self._data[self.x_field][0] > self._data[self.x_field][-1]:
+            xmin, xmax = xmax, xmin
+        if self._data[self.y_field][0] > self._data[self.y_field][-1]:
+            ymin, ymax = ymax, ymin
+        return xmin, ymin, xmax, ymax

tests/pygeoapi-test-config.yml

@@ -314,28 +314,27 @@ resources:
                   name: NetCDF
                   mimetype: application/x-netcdf
 
-    nasa-power:
+    usgs-prism:
         type: collection
-        title: NASA Prediction Of Worldwide Energy Resources (POWER)
+        title: Parameter-elevation Regressions on Independent Slopes Model (PRISM)
-        description: NASA Prediction Of Worldwide Energy Resources (POWER)
+        description: PRISM Monthly Climate Data for the Continental United States
         keywords:
-            - nasa
+            - temperature
-            - energy
+            - precipitation
-            - power
         extents:
             spatial:
-                bbox: [-180,-90,180,90]
+                bbox: [-125.020836, 24.104166, -66.520836, 49.9375]
                 crs: http://www.opengis.net/def/crs/OGC/1.3/CRS84
         links:
             - type: text/html
               rel: canonical
               title: information
-              href: https://power.larc.nasa.gov/
+              href: https://cida.usgs.gov/thredds/catalog.html?dataset=cida.usgs.gov/prism_v2
               hreflang: en-US
         providers:
             - type: edr
               name: xarray-edr
-              data: s3://power-analysis-ready-datastore/power_901_annual_meteorology_utc.zarr
+              data: s3://mdmf/gdp/PRISM_v2.zarr
               format:
                   name: zarr
                   mimetype: application/zip
@@ -343,6 +342,8 @@ resources:
                   s3:
                     anon: true
                     requester_pays: false
+                    client_kwargs:
+                        endpoint_url: https://usgs.osn.mghpcc.org/
     
     objects:
         type: collection

tests/test_api.py

@@ -2002,15 +2002,6 @@ def test_get_collection_edr_query(config, api_):
         req, 'icoads-sst', None, 'position')
     assert code == HTTPStatus.NO_CONTENT
 
-    # S3 EDR
-    req = mock_request({
-        'coords': 'POINT(-100 40)',
-        'parameter-name': 'GWETROOT'
-    })
-    rsp_headers, code, response = api_.get_collection_edr_query(
-        req, 'nasa-power', None, 'position')
-    assert code == HTTPStatus.OK
-
     # position no coords
     req = mock_request({
         'datetime': '2000-01-17'
@@ -2041,6 +2032,17 @@ def test_get_collection_edr_query(config, api_):
         req, 'icoads-sst', None, 'cube')
     assert code == HTTPStatus.BAD_REQUEST
 
+    # cube decreasing latitude coords and S3
+    req = mock_request({
+        'bbox': '-100,40,-99,45',
+        'parameter-name': 'tmn',
+        'datetime': '1994-01-01/1994-12-31',
+    })
+
+    rsp_headers, code, response = api_.get_collection_edr_query(
+        req, 'usgs-prism', None, 'cube')
+    assert code == HTTPStatus.OK
+
 
 def test_validate_bbox():
     assert validate_bbox('1,2,3,4') == [1, 2, 3, 4]