Adding check for NWM stream segments within HUC boundaries

This merge modifies clip_vectors_to_wbd.py to check for relevant input data.

- clip_vectors_to_wbd.py now checks that there are NWM stream segments within the buffered HUC boundary.
- included_huc8_ms.lst has several additional HUC8s.

CHANGELOG.md

@@ -2,6 +2,16 @@ All notable changes to this project will be documented in this file.
 We follow the [Semantic Versioning 2.0.0](http://semver.org/) format.
 <br/><br/>
 
+## v3.0.20.2 - 2021-08-13 - [PR #443](https://github.com/NOAA-OWP/cahaba/pull/443)
+
+This merge modifies `clip_vectors_to_wbd.py` to check for relevant input data.
+
+## Changes
+- `clip_vectors_to_wbd.py` now checks that there are NWM stream segments within the buffered HUC boundary.
+- `included_huc8_ms.lst` has several additional HUC8s.
+
+<br/><br/>
+
 ## v3.0.20.1 - 2021-08-12 - [PR #442](https://github.com/NOAA-OWP/cahaba/pull/442)
 
 This merge improves documentation in various scripts.

src/clip_vectors_to_wbd.py

@@ -127,7 +127,11 @@ def subset_vector_layers(hucCode,nwm_streams_filename,nhd_streams_filename,nwm_l
     nwm_streams = gpd.read_file(nwm_streams_filename, mask = wbd_buffer)
     if extent == 'MS':
         nwm_streams = nwm_streams.loc[nwm_streams.mainstem==1]
-    nwm_streams.to_file(subset_nwm_streams_filename,driver=getDriver(subset_nwm_streams_filename),index=False)
+    if len(nwm_streams) > 0:
+        nwm_streams.to_file(subset_nwm_streams_filename,driver=getDriver(subset_nwm_streams_filename),index=False)
+    else:
+        print ("No NWM stream segments within HUC " + str(hucCode) +  " boundaries.")
+        sys.exit(0)
     del nwm_streams
 
 if __name__ == '__main__':