[GRASS-dev] v.lidar category numbers

[Markus Neteler]

On Fri, Jun 19, 2009 at 1:27 PM, Hamish<hamish_b at yahoo.com> wrote:
> Hi,
>
> I'm a bit confused with v.lidar EDGE/TERRAIN/UNKNOWN #defines.
>
> v.lidar.edgedetection categorizes data points as either of those three.
>
> output vector map includes cats 0,1,2 by layer 1.
>  (also there is a DB on layer 3, but that is not important to this email)
>
>
> man page says:
>  EDGE (cat = 1, layer = 1)
>  TERRAIN (cat = 2, layer = 1)
> (so cat=0 is UNKNOWN ??)
>
>
> vector/lidar/v.lidar.edgedetection/edgedetection.c has:
>    /* 0 = PRE_TERRAIN */
>    /* 1 = PRE_EDGE */
>    /* 2 = UNKNOWN */
>
>
> vector/lidar/lidarlib/PolimiFunct.h has:
>    /* PRE-CLASSIFICATION */
> #define PRE_TERRAIN             1
> #define PRE_EDGE                2
> #define PRE_UNKNOWN             3
>
>
> In v.lidar.growing I don't see any of these clearly but I guess they
> must be there.
>
>
> ... I am a little confused. I'd like to update the v.lidar.edgedetection
> man page to say what cat 0 in its output means.
>

Via Maria Brovelli/Sara Lucca I obtained this answer

----- start cite -----
The output of v.lidar.edgetection is:
TERRAIN (cat = 1, layer = 1)
EDGE (cat = 2, layer = 1)
UNKNOWN (cat = 3, layer = 1)

Nothing correspond to category 0.

So the correct classification is the one in the PolimiFunct.h

    vector/lidar/lidarlib/
    PolimiFunct.h has:
       /* PRE-CLASSIFICATION */
    #define PRE_TERRAIN             1
    #define PRE_EDGE                2
    #define PRE_UNKNOWN             3


In the man page there is an error, in fact the category referring to
terrain and edge are switched:


    man page says:
     EDGE (cat = 1, layer = 1)
     TERRAIN (cat = 2, layer = 1)
    (so cat=0 is UNKNOWN ??)


The comment in the file edgedetection.c is wrong, probably it is
something left from an old version of the code:

    vector/lidar/v.lidar.

    edgedetection/edgedetection.c has:
       /* 0 = PRE_TERRAIN */
       /* 1 = PRE_EDGE */
       /* 2 = UNKNOWN */

----- end cite -----

Markus