Re: Getting PDOP, VDOP and HDOP in C

[Gary E. Miller]

Yo David!

On Tue, 29 Mar 2022 05:29:15 +0100
David Taylor <gm8arv@yahoo.co.uk> wrote:

> I have a program which returns a valid gps_data_t named gps_data.  My
> knowledge and reading of the headers isn't good enough to find how to
> get the three variables: pdop, hdop and vdop, although I suspect they
> are available.  Could some kind soul show me how, please?
> 
> given in outline:
> 
>    struct gps_data_t gpsdata;
>    status = gps_open (GPSD_SHARED_MEMORY, DEFAULT_GPSD_PORT,
> &gpsdata); gps_read (&gpsdata, NULL, 0);
> 
>    hdop = gpsdata.<what>
>    vdop = gpsdata.<what>
>    pdop = gpsdata.<what>


Looking in include/gps.h, one should not be surprised to find:

    gpsdata.dop.xdop
    gpsdata.dop.ydop
    gpsdata.dop.pdop
    gpsdata.dop.hdop
    gpsdata.dop.vdop
    gpsdata.dop.tdop
    gpsdata.dop.gdop
  
That said, the DOPs are not very useful in real life.  Better to look
at the epX, which are only slightly less fanciful.

RGDS
GARY
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Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
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