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wpietri / simpleais

A simple Python AIS parser intended for casual use.
GNU Lesser General Public License v3.0
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Incorrect longitude/latitude scaling for message 27 #2

Closed prgbwt closed 7 months ago

prgbwt commented 1 year ago

First, thanks for your work on simpleais, it is quite useful.

I noticed that simpleais reports bad longitude/latitude values for message 27. The root cause appears to be that _parse_lon/_parse_lat use a scale factor of 4 (10^4) regardless of message type, which gives incorrect results for message 27. Message 27 longitude/latitude has a lower resolution (degrees/10) than other AIS message types (degrees/10000).

Excerpt from the standard: image

Cheers

wpietri commented 7 months ago

Thanks, this should be fixed in #5.