[Liblas-devel] Re: Writing Scan Angle Rank values

[Howard Butler]

On May 1, 2008, at 1:11 PM, Howard Butler wrote:

> Mateusz,
>
> The specification says the following for Scan Angle:
>
> Scan Angle Rank (-90 to +90) – Left side unsigned char 1 byte *
>
> We are doing the following:
> int8_t GetScanAngleRank() const;
> void SetScanAngleRank(int8_t const& rank);
>
> int8_t is defined as:
>
> typedef signed char     int8_t;
>
>
> If I write the following:
> p = point.Point()
> p.scan_angle = -90
>
> The Scan Angle returned is:
>
> Scan Angle Rank:	166
>
>
> Do you have any idea why the Scan Angle Ranks cannot be  
> roundtripped?  I would expect the Scan Angle Rank to be -90 in the  
> file as I have set it.  The specification is unclear to me.  If we  
> are supposed to store Scan Angle Rank as an unsigned char, how are   
> we to store negative values?  Are we supposed to determine +/- from  
> the Scan Direction and then store 0-90 in the Scan Angle Rank?


My dumb.  I was using uint8_t in the C API and clipping things off.   
Sorry.  Fixed in r626 http://liblas.org/changeset/626/

Howard