[GRASS-dev] Why the parameters of "g.region" are defined as string?

GRASS GIS GRASS GIS developer
1

Hi all,

Today I've just realize that the parameter of g.region are defined as string:

http://trac.osgeo.org/grass/browser/grass/trunk/general/g.region/main.c#L203

for example:

{{{
    parm.north = G_define_option();
    parm.north->key = "n";
    parm.north->key_desc = "value";
    parm.north->required = NO;
    parm.north->multiple = NO;
    parm.north->type = TYPE_STRING;
    parm.north->description = _("Value for the northern edge");
    parm.north->guisection = _("Bounds");
}}}

Why should we not use TYPE_DOUBLE for these parameters (n,s,e,w,)? Is
it to not loose significant digits?

Sorry if this has already been discussed, but I was not able to find
any reference in the mailing-list's archive.

Best regards

Pietro

2

On 08/12/2013 05:39 PM, Pietro wrote:

Hi all,

Today I've just realize that the parameter of g.region are defined as string:

http://trac.osgeo.org/grass/browser/grass/trunk/general/g.region/main.c#L203

[snip]

Why should we not use TYPE_DOUBLE for these parameters (n,s,e,w,)? Is
it to not loose significant digits?

It needs to be a string, so that you can use
common lat/lon notations in the format "°dd'mm''ss".

Ben

Sorry if this has already been discussed, but I was not able to find
any reference in the mailing-list's archive.

Best regards

Pietro
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Dr. Benjamin Ducke, M.A.
{*} Geospatial Consultant
{*} GIS Developer

   benducke@fastmail.fm

3

On Mon, Aug 12, 2013 at 4:54 PM, Benjamin Ducke <benducke@fastmail.fm> wrote:

On 08/12/2013 05:39 PM, Pietro wrote:

http://trac.osgeo.org/grass/browser/grass/trunk/general/g.region/main.c#L203

Why should we not use TYPE_DOUBLE for these parameters (n,s,e,w,)? Is
it to not loose significant digits?

It needs to be a string, so that you can use
common lat/lon notations in the format "°dd'mm''ss".

Thank you Ben! I didn't thought to the lat/lon notation.

Best regards

Pietro

4

Ben:

It needs to be a string, so that you can use
common lat/lon notations in the format "°dd'mm''ss".

technically it's like ddd:mm:ss.ssssH.
see the v.in.ascii man page. fwiw GMT mapping uses something similar.

regards,

Hamish

ps- the wxgui loc'n wizard still doesn't support that? :frowning: