[GRASSLIST:10327] Re: v.digit additions

[Ralf Gerlich]

Hi,

thanks to Markus, these changes are in CVS now - with a little 
additional fix.

Cheers,
Ralf

Ralf Gerlich schrieb:
> Hello,
> 
> I have created some additions to v.digit, namely
> 
> 1. the possibility to change the width of displayed lines in the 
> settings dialog,
> 2. a tool for continuous appending of points to a previously closed 
> line, and
> 3. a tool for copying categories between features.
> 
> I have attached the separated patches in a tar.gz together with the 
> additional icons.
> 
> ad 1.
> =====
> 
> On some raster maps the 1-pixel wide lines and point-markers are hard to 
> see, even when changing the colors. This patch enables setting of the 
> width of such lines in the settings dialog.
> 
> The patch is a bit quick-and-dirty, but worked fine so far.
> 
> ad 2.
> =====
> 
> When digitising large objects on a large scale, these objects tend to 
> cross the display border. In that case, one has to stop digitising the 
> line or boundary, pan the view and continue editing. While "add vertex" 
> allows for adding vertices anywhere in the line, it is tedious to use 
> when continuing at the end, as for any additional vertex two clicks are 
> necessary.
> 
> Simply starting with a new line adds an additional node where none is 
> topologically required and in case of many occurrences of such nodes 
> may, e.g., prevent "v.clean tool=prune" from doing proper simplification 
> (which is important for my application of creating custom scenery for 
> the open source flight simulator FlightGear)
> 
> The "edit line" tool allows the user to select one end of a line and 
> continue editing as if the line was newly created, including deletion of 
> previous vertices using button 2 up to the first vertex, resulting in 
> the deletion of the line.
> 
> ad 3.
> =====
> 
> When digitising discontinuous but related features it may be desirable 
> for the parts to have the same categories, pointing to the same table rows.
> 
> I am now in a situation where I have a considerable data set with 
> related features being assigned different categories. The "copy 
> categories" tool allows you to copy the categories of one feature to 
> another. Simply select the source feature and the target feature and 
> confirm by clicking once with button 1. The categories are copied from 
> source to target and the old categories of the target are deleted using 
> check_record(). The old target becomes the new source and you can select 
> a new target by the next click with button 1.
> 
> =====
> 
> I am not sure if any of this is actually useful for others and whether I 
> did these things the right way, but I tought, I'd share them.
> 
> Best Regards,
> Ralf