fixed interpolation. Added alerts for different cases. e.g. no speed data available.
fixed interpolation. Added alerts for different cases. e.g. no speed data available.

IFGI-Geosoftware2-GroupA/envirocar-analyser,IFGI-Geosoftware2-GroupA/envirocar-analyser,IFGI-Geosoftware2-GroupA/envirocar-analyser