fixed int64 time overlfow, fixes #445

clients/python/sliderule/raster.py

@@ -134,6 +134,9 @@ def sample(asset, coordinates, parms={}):
             **columns
         }
 
+    # GPS Offset between unix epoch and gps epoch in milliseconds
+    gps_offset_msecs = 315964800.0 * 1000
+
     # Populate Columns
     i = 0
     per_coord_index = 0
@@ -142,7 +145,7 @@ def sample(asset, coordinates, parms={}):
         latitude = coordinates[per_coord_index][1]
         per_coord_index += 1
         for raster_sample in input_coord_response:
-            columns['time'][i] = numpy.int64((raster_sample['time'] + 315964800.0) * 1000000000)
+            columns['time'][i] = numpy.int64((raster_sample['time'] + gps_offset_msecs) * 1e6) # int64 with gps nanoseconds will overflow in year 2272
             columns['longitude'][i] = numpy.double(longitude)
             columns['latitude'][i] = numpy.double(latitude)
             columns['file'] += raster_sample['file'],

clients/python/tests/test_worldcover.py

@@ -3,6 +3,8 @@
 import pytest
 from pathlib import Path
 import sliderule
+from sliderule import raster
+import geopandas as gpd
 
 TESTDIR = Path(__file__).parent
 
@@ -24,3 +26,26 @@ def test_vrt(self, init):
         assert abs(rsps["samples"][0][0]["value"] - vrtValue) < sigma
         assert rsps["samples"][0][0]["file"] ==  vrtFile
         assert rsps["samples"][0][0]["time"] ==  vrtFileTime
+
+    def test_time_overflow(self, init):
+        region = [  {"lon": -108.34, "lat": 38.89},
+                    {"lon": -107.76, "lat": 38.90},
+                    {"lon": -107.78, "lat": 39.26},
+                    {"lon": -108.36, "lat": 39.25},
+                    {"lon": -108.34, "lat": 38.89}  ]
+
+        gfp = gpd.GeoDataFrame(geometry=gpd.points_from_xy([-108.1, -108.3], [39.1, 39.2]), crs='EPSG:4326')
+        points = [[x,y] for x,y in zip(gfp.geometry.x , gfp.geometry.y)]
+        gdf = raster.sample("esa-worldcover-10meter", points)
+
+        expected_time  = "2021-06-30 00:00:18"
+        expected_value = 10.0
+
+        # Check if all timestamps match the expected_time (used as index)
+        assert all(str(index) == expected_time for index in gdf.index), \
+            f"Time mismatch. Expected: {expected_time}, Found: {gdf.index.tolist()}"
+
+        # Check if all values match the expected value
+        assert all(gdf["value"] == expected_value), \
+            f"Value mismatch. Expected: {expected_value}, Found: {gdf['value'].tolist()}"
+