Merge branch 'doc-update-readmes' into 'master'

Bug fixes and README updates

See merge request cspp_geo/cspp-geo-web-viewer!11

mapserver/README.md

 # MapServer
 
+## Build
+
+```bash
+docker build -t gitlab.ssec.wisc.edu:5555/cspp_geo/cspp-geo-web-viewer/mapserver:latest mapserver/
+```
+
 ## Usage
 
 ```bash
-docker run -p 8888:80 -d --rm --name cspp-geo-mapserver -v cspp-geo-abi-l1b-geotiffs:/data gitlab.ssec.wisc.edu:5555/cspp_geo/cspp-geo-web-viewer/mapserver:latest
+docker run -p 8888:80 -d --rm --name cspp-geo-mapserver --network cspp-geo-rabbit -v cspp-geo-abi-l1b-geotiffs:/data gitlab.ssec.wisc.edu:5555/cspp_geo/cspp-geo-web-viewer/mapserver:latest
 ```
 
 Then the main mapserv CGI script can be accessed with:
 
 http://localhost:8888/cgi-bin/mapserv
 
+where MapServer parameters can be appended to the end (after a `?`). However,
+an easier to access API is available:
+
+```bash
+http://localhost:8888/wms/<satellite>/<instrument>/<sector>/<data_level>?...
+```
+
+An example URL of this including MapServer parameters is:
+
+```bash
+http://localhost:8888/wms/g16/abi/radf/l1b?request=GetMap&service=WMS&version=1.1.1&srs=EPSG:930916&layers=true_color_test&bbox=-5000000,-5000000,5000000,5000000&format=image/png&WIDTH=1000&HEIGHT=1000&TIME=2020-01-21T16:00:16
+```
+
 ## Special Notes
 
 This image has had its installation of the PROJ library modified to include

mapserver/cgi-bin/layer_times.py

 #!/usr/bin/env python3
+import os
 import cgi
 import json
 import fiona
 
 form = cgi.FieldStorage()
 layer = form['layer'].value
-with fiona.open(layer, 'r') as shp_file:
-    times = [x['properties']['time'] for x in shp_file]
+if not os.path.isfile(layer):
+    times = []
+else:
+    with fiona.open(layer, 'r') as shp_file:
+        times = [x['properties']['time'] for x in shp_file]
 
 print("Content-Type: application/json")
 print("Access-Control-Allow-Origin: *")

tile_gen/tile_index.py

@@ -110,7 +110,7 @@ def index(input_files, output_shapefile):
     shutil.rmtree(tmp_dir, ignore_errors=True)
 
     times_removed = current_times - new_times
-    times_added = new_times = current_times
+    times_added = new_times - current_times
     return sorted(times_removed), sorted(times_added)