fix: Parse negative altitudes from surveys

coordinator/ProcessorSurveyUtils.py

@@ -19,7 +19,7 @@ def parse_location_str(location_str):
 
     # expecting a space-separated string containing four numbers which
     # contain a decimal point
-    regex = r'(?P<lat>[-?0-9\.]+)\s(?P<lon>[-?0-9\.]+)\s(?P<alt>[0-9\.]+)\s(?P<acc>[0-9\.]+)'
+    regex = r'(?P<lat>-?[0-9\.]+)\s(?P<lon>-?[0-9\.]+)\s(?P<alt>-?[0-9\.]+)\s(?P<acc>[0-9\.]+)'
 
     # needed because the ODK names are too complicated for regex named groups
     name_dict = {