[GRASS-dev] v.mkgrid - why 2 extra nodes in horizontal boundaries?

GRASS GIS GRASS GIS developer
1

Hi

I'm not sure if this is a defect or a feature for a purpose,
thus asking first.

v.mkgrid always creates areas with horizontal boundaries
having 2 extra nodes (see attached screendump from v.digit).
I can't see a reason why extra nodes are necesssary.
Vertical boundaries don't have them...

Maciek

2

Maciej Sieczka wrote:

v.mkgrid always creates areas with horizontal boundaries
having 2 extra nodes (see attached screendump from v.digit).

Forgot to attach. Here it is.

Maciek

(attachments)

extra_nodes.png

3

Maciej Sieczka wrote:

I'm not sure if this is a defect or a feature for a purpose,
thus asking first.

v.mkgrid always creates areas with horizontal boundaries
having 2 extra nodes (see attached screendump from v.digit).
I can't see a reason why extra nodes are necesssary.
Vertical boundaries don't have them...

from vector/v.mkgrid/write_grid.c:
/*
* For latlon, must draw in shorter sections
* to make sure that each section of the grid
* line is less than half way around the globe
*/
  x_len = length/3.;
  x_cols = cols*3.;

Hamish