[GRASS-user] Convert vector map from line to boundary/area

   I have done something incorrectly trying to create a mask and need a
clue-stick to correct the situation. Here's what I did:

   1. Digitized a line to define an area on a base raster map; saved it as
   anal_area_mask.

   2. v.to.rast in=bndy_conditions type=area out=anal_area_mask use=cat

   3. Removed existing mask: r.mask -r

   4. Created new mask: r.mask rast=anal_area_mask

   5. Selected a raster map in the Layer Manager window.

   6. No map displayed in the Map Display window; it's plain white.

   Did editing the digitized line to an area, and saving it as a line, affect
how it was converted to a raster map? Yep.

   If I change the vector map type from line to boundary or area it is not
visible.

   How do I convert this vector line to either a boundary or area (whichever
is appropriate) so it produces a raster mask?

Rich

On 07/04/17 00:57, Rich Shepard wrote:

   I have done something incorrectly trying to create a mask and need a
clue-stick to correct the situation. Here's what I did:

   1. Digitized a line to define an area on a base raster map; saved it as
   anal_area_mask.

   2. v.to.rast in=bndy_conditions type=area out=anal_area_mask use=cat

   3. Removed existing mask: r.mask -r

   4. Created new mask: r.mask rast=anal_area_mask

   5. Selected a raster map in the Layer Manager window.

   6. No map displayed in the Map Display window; it's plain white.

   Did editing the digitized line to an area, and saving it as a line, affect
how it was converted to a raster map? Yep.

   If I change the vector map type from line to boundary or area it is not
visible.

   How do I convert this vector line to either a boundary or area (whichever
is appropriate) so it produces a raster mask?

1) Convert the line from type line to type boundary (v.type).
2) Add a centroid inside the area (v.centroids)

Moritz

On Fri, 7 Apr 2017, Moritz Lennert wrote:

1) Convert the line from type line to type boundary (v.type).

Moritz,

   I missed seeing v.type when I went through the list of modules. I was
looking for something like this.

2) Add a centroid inside the area (v.centroids)

   Yes, v.centroids does nothing when it's only a line.

Many thanks,

Rich