I have a small section of road as an area. I want to convert one edge to a
line. I displayed the map and selected 'Vector digitizer' and the name of
the map. Clicking the icon for 'Delete selected boundaries, etc.' I removed
the corners and centroid, leaving one edge of the road visible.
However, when I clicked the 'Quit digitizer' icon the display shows the
unedited area rather than the single line. Seems to me from the last time I
used the GUI digitizer on a vector map that the changes were saved to the
same map name when I quit editing.
Any thoughts on what I missed?
Rich
Hi Rich
I think you’ll have to convert the boundary to a line first, with v.type. Then edit the line. (Similar to what Helmut suggested previously)
···
On 2017-06-07 23:37 PM, Rich Shepard wrote:
I have a small section of road as an area. I want to convert one edge to a
line. I displayed the map and selected ‘Vector digitizer’ and the name of
the map. Clicking the icon for ‘Delete selected boundaries, etc.’ I removed
the corners and centroid, leaving one edge of the road visible.
However, when I clicked the ‘Quit digitizer’ icon the display shows the
unedited area rather than the single line. Seems to me from the last time I
used the GUI digitizer on a vector map that the changes were saved to the
same map name when I quit editing.
Any thoughts on what I missed?
Rich
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Micha Silver
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On Thu, 8 Jun 2017, Micha Silver wrote:
I think you'll have to convert the boundary to a line first, with v.type.
Then edit the line. (Similar to what Helmut suggested previously)
Micha,
I should have provided an update to this thread and apologize for not
doing so. Because modification of the road area to a single line was not
working for me I created a new map in the GUI vector editor by digitizing
a line over the area's edge. This new map, 'cutline,' is a single line, not
a boundary, as confirmed by v.info.
This still leaves the issue of overlaying the line on the area in such a
way that the area is divided in two parts (v.overlay is not doing the job or
I'm not correctly specifying the command), then rasterizing the two adjacent
areas so each can have a separate value in each cell. The former task is
where I'm stuck. I assume that for the latter task I can run v.to.rast twice
and produce new maps, e.g., 'upper' and 'lower', then use the GII digitizer
to remove all unwanted cells prior to setting values then pasting the two
parts back together.
Regards,
Rich
On Thu, 8 Jun 2017, Rich Shepard wrote:
This still leaves the issue of overlaying the line on the area in such a
way that the area is divided in two parts (v.overlay is not doing the job or
I'm not correctly specifying the command)
Ah, mea culpa! v.patch will do the job.
Rich