Merge pull request #1649 from smathermather/proj4-guidance

Update proj4 string guidance

opendm/location.py

@@ -151,6 +151,8 @@ def parse_srs_header(header):
                             ' - EPSG:*****\n'
                             ' - WGS84 UTM **(N|S)\n'
                             ' - Any valid proj4 string (for example, +proj=utm +zone=32 +north +ellps=WGS84 +datum=WGS84 +units=m +no_defs)\n\n'
+                            ' Some valid EPSG codes are not yet available in OpenDroneMap and need substituted with valid proj4 strings\n'
+                            ' Try searching for equivalent proj4 strings at spatialreference.org or epsg.io.\n'
                             'Modify your input and try again.' % header)
         raise RuntimeError(e)
     
@@ -165,4 +167,4 @@ def utm_transformers_from_ll(lon, lat):
     target_srs = utm_srs_from_ll(lon, lat)
     ll_to_utm = transformer(source_srs, target_srs)
     utm_to_ll = transformer(target_srs, source_srs)
-    return ll_to_utm, utm_to_ll
+    return ll_to_utm, utm_to_ll