Addresses DEM download issues

CHANGELOG.md

@@ -6,6 +6,11 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [PEP 440](https://www.python.org/dev/peps/pep-0440/)
 and uses [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.5.3]
+* Change "OPERA DEM" references to "Modified Copernicus DEM for NISAR"
+* Update Modified Copernicus DEM for NISAR endpoints for v1.2
+* Add `fetch.download_file()` exception handling and delete partial downloads
+
 ## [0.5.2]
 
 ### Fixed

src/multirtc/dem.py

@@ -15,7 +15,7 @@
 
 
 gdal.UseExceptions()
-URL = 'https://nisar.asf.earthdatacloud.nasa.gov/STATIC/DEM/v1.1/EPSG4326'
+URL = 'https://nisar.asf.earthdatacloud.nasa.gov/NISAR/DEM/v1.2/EPSG4326'
 EGM2008_GEOID = {
     'WORLD': [
         '/vsicurl/https://asf-dem-west.s3.amazonaws.com/GEOID/us_nga_egm2008_1.tif',
@@ -118,7 +118,7 @@ def check_antimeridean(poly: Polygon) -> list[Polygon]:
 
 
 def get_dem_granule_url(lat: int, lon: int) -> str:
-    """Generate the URL for the OPERA DEM granule based on latitude and longitude.
+    """Generate the URL for the Modified Copernicus DEM for NISAR granule based on latitude and longitude.
 
     Args:
         lat: Latitude in degrees.
@@ -133,8 +133,8 @@ def get_dem_granule_url(lat: int, lon: int) -> str:
     lon_tens = np.floor_divide(lon, 20) * 20
     lon_cardinal = 'W' if lon_tens < 0 else 'E'
 
-    prefix = f'{lat_cardinal}{np.abs(lat_tens):02d}_{lon_cardinal}{np.abs(lon_tens):03d}'
-    filename = f'DEM_{lat_cardinal}{np.abs(lat):02d}_00_{lon_cardinal}{np.abs(lon):03d}_00.tif'
+    prefix = f'{lat_cardinal}{np.abs(lat_tens):02d}/{lat_cardinal}{np.abs(lat_tens):02d}_{lon_cardinal}{np.abs(lon_tens):03d}'
+    filename = f'DEM{lat_cardinal}{np.abs(lat):02d}_00_{lon_cardinal}{np.abs(lon):03d}_00_C01.tif'
     file_url = f'{URL}/{prefix}/{filename}'
     return file_url
 
@@ -156,7 +156,7 @@ def get_latlon_pairs(polygon: Polygon) -> list[tuple[float, float]]:
 
 def download_opera_dem_for_footprint(output_path: Path, footprint: Polygon, buffer: float = 0.2) -> None:
     """
-    Download the OPERA DEM for a given footprint and save it to the specified output path.
+    Download the Modified Copernicus DEM for NISAR for a given footprint and save it to the specified output path.
 
     Args:
         output_path: Path where the DEM will be saved.

src/multirtc/fetch.py

@@ -63,13 +63,22 @@ def download_file(
     session.mount('https://', HTTPAdapter(max_retries=retry_strategy))
     session.mount('http://', HTTPAdapter(max_retries=retry_strategy))
 
-    with session.get(url, stream=True) as s:
-        download_path = _get_download_path(s.url, s.headers.get('content-disposition'), directory)
-        s.raise_for_status()
-        with open(download_path, 'wb') as f:
-            for chunk in s.iter_content(chunk_size=chunk_size):
-                if chunk:
-                    f.write(chunk)
-    session.close()
+    download_path = None
+    try:
+        with session.get(url, stream=True) as s:
+            download_path = _get_download_path(s.url, s.headers.get('content-disposition'), directory)
+            s.raise_for_status()
+            with open(download_path, 'wb') as f:
+                for chunk in s.iter_content(chunk_size=chunk_size):
+                    if chunk:
+                        f.write(chunk)
+            logging.info(f'Download successful: {url}')
+    except requests.exceptions.RequestException as e:
+        logging.exception(f'Download failed: {url}')
+        if download_path is not None:
+            download_path.unlink(missing_ok=True) # delete any partial downloads
+        raise
+    finally:
+        session.close()
 
     return str(download_path)

tests/test_dem.py

@@ -4,7 +4,7 @@
 
 
 def test_get_granule_url():
-    test_url = 'https://nisar.asf.earthdatacloud.nasa.gov/STATIC/DEM/v1.1/EPSG4326/S10_W020/DEM_S01_00_W001_00.tif'
+    test_url = 'https://nisar.asf.earthdatacloud.nasa.gov/NISAR/DEM/v1.2/EPSG4326/S10/S10_W020/DEMS01_00_W001_00_C01.tif'
     url = dem.get_dem_granule_url(-1, -1)
     assert url == test_url