[GRASS-user] PS.MAP order of layers

GRASS GRASS user
,
1

Timothy wrote:

I am using rasters, areas, borders, and points in an eps file
using ps.map. I want the points to be placed under an area
layer, because I only want the relevant points to a specific
country to be seen. Not matter what order I put the
commands in (vpoints before or after varea), the points appear
on top. I am running GRASS 6.4 in the Linux environment.
Any thoughts on what to do to make this work?

add "masked y" to the vpoints instruction.

(the help page for ps.map is somewhat misleading about what the
masked instruction really does, and if the ordering works among
different feature types)

#spearfish example
g.region -d
ps.map out=test.ps << EOF
raster elevation.dem
vareas fields
  end
vpoints archsites
  masked y
  end
end
EOF

gv test.ps

as a last resort you can use v.select to crop out the non-
overlapping points (maybe use its geos op=disjoint option or
invert the area with v.in.region+v.overlay first); or try
v.overlay on its own for "point not in polygon".

Hamish

2

Hi,

On Thu, Jun 14, 2012 at 7:27 AM, Hamish <hamish_b@yahoo.com> wrote:

Timothy wrote:

I am using rasters, areas, borders, and points in an eps file
using ps.map. I want the points to be placed under an area
layer, because I only want the relevant points to a specific
country to be seen. Not matter what order I put the
commands in (vpoints before or after varea), the points appear
on top. I am running GRASS 6.4 in the Linux environment.
Any thoughts on what to do to make this work?

add "masked y" to the vpoints instruction.

(the help page for ps.map is somewhat misleading about what the
masked instruction really does, and if the ordering works among
different feature types)

I haven't noticed it before. In my point of view it's a bug. Either
the help page or better ps.map should be changed. Ordering seems to
work for areas and line layers so is there any reason why point layers
behave in a different way?

Anna

#spearfish example
g.region -d
ps.map out=test.ps << EOF
raster elevation.dem
vareas fields
end
vpoints archsites
masked y
end
end
EOF

gv test.ps

as a last resort you can use v.select to crop out the non-
overlapping points (maybe use its geos op=disjoint option or
invert the area with v.in.region+v.overlay first); or try
v.overlay on its own for "point not in polygon".

Hamish
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3

Thanks for your helpful suggestions! I used "masked y" as my initial solution. After doing that, I discovered that I wanted the points under some layers and over other layers, so I solved that next problem by using "masked y" for the layers that I wanted it on top of. Ultimately, I think using the pre-selecting points idea will be the most elegant solution, but I have not had time yet to implement that. I do agree with Anna's suggestion that it would be more natural to treat point vectors like area or line vectors in regard to their order. In the shorter-term, perhaps re-wording the manual might be helpful.

Thanks again for your help!

   Tim

***************************************************************
Timothy S. Thomas, Research Fellow, IFPRI
t.s.thomas@cgiar.org +1-202-862-4605 skype: timothy.s.thomas Rm 5035

-----Original Message-----
From: Anna Kratochvílová [mailto:kratochanna@gmail.com]
Sent: Thursday, June 14, 2012 3:18 AM
To: Hamish
Cc: Thomas, Timothy (IFPRI); grass-user@lists.osgeo.org
Subject: Re: [GRASS-user] PS.MAP order of layers

Hi,

On Thu, Jun 14, 2012 at 7:27 AM, Hamish <hamish_b@yahoo.com> wrote:

Timothy wrote:

I am using rasters, areas, borders, and points in an eps file using
ps.map. I want the points to be placed under an area layer, because
I only want the relevant points to a specific country to be seen.
Not matter what order I put the commands in (vpoints before or after
varea), the points appear on top. I am running GRASS 6.4 in the
Linux environment.
Any thoughts on what to do to make this work?

add "masked y" to the vpoints instruction.

(the help page for ps.map is somewhat misleading about what the masked
instruction really does, and if the ordering works among different
feature types)

I haven't noticed it before. In my point of view it's a bug. Either the help page or better ps.map should be changed. Ordering seems to work for areas and line layers so is there any reason why point layers behave in a different way?

Anna

#spearfish example
g.region -d
ps.map out=test.ps << EOF
raster elevation.dem
vareas fields
end
vpoints archsites
masked y
end
end
EOF

gv test.ps

as a last resort you can use v.select to crop out the non- overlapping
points (maybe use its geos op=disjoint option or invert the area with
v.in.region+v.overlay first); or try v.overlay on its own for "point
not in polygon".

Hamish
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