[GRASSLIST:9952] v.digit additions

GRASS GRASS user
1

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

(attachments)

patches.tar.gz (4.96 KB)

2

These sound like very helpful additions.

Since you are looking at v.digit, I'd like to ask if it looks like v.digit
can be modified so that it doesn't require an x-display to run?

Michael
______________________________
Michael Barton, Professor of Anthropology
School of Human Evolution and Social Change
Arizona State University
Tempe, AZ 85287-2402
USA

voice: 480-965-6262; fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton

From: Ralf Gerlich <ralf.gerlich@bsse.biz>
Date: Mon, 23 Jan 2006 12:48:56 +0100
To: GRASSLIST <grasslist@baylor.edu>
Subject: [GRASSLIST:9952] v.digit additions

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

3

Michael Barton wrote:

These sound like very helpful additions.

Since you are looking at v.digit, I'd like to ask if it looks like v.digit
can be modified so that it doesn't require an x-display to run?

Not really. v.digit is inherently interactive, and needs to be
re-written.

Apart from anything else, v.digit is based around modal input, whereas
all modern UI toolkits are event-driven.

--
Glynn Clements <glynn@gclements.plus.com>

4

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