[GRASS-user] ps.map and line style

GRASS GRASS user
1

Hello,
in a map composition I need to draw contours with two particular
linestyles:
- a line bedecked with crosses: ----x----x----x----x----
- a double line: =====================

I am wondering if there is a simple way to specify e.g. a postscript
linear pattern that applies to vlines, the same way we can with vareas.

Any idea ?

Vincent

2

Vincent Bain wrote:

Hello,
in a map composition I need to draw contours with two particular
linestyles:
- a line bedecked with crosses: ----x----x----x----x----
- a double line: =====================
  

Hi Vincent,

I have plotted a double line like this:

vlines my_lines
    color yellow
    width 1.5
    label Chirp lines
    lpos 4
    style 000111
end

vlines my_lines
    color black
    width 3
    label Chirp lines
    lpos 4
    style 000111
end

The top entry in the file plots on top in the map. This gives a black dotted line with a yellow middle. Specifying the same legend position recreates the pattern in the legend.

Later

John

--

Dr John Stevenson
Postdoctoral Research Associate
School of Earth, Atmospheric and Environmental Sciences
Williamson Building (Room 2.42)
University of Manchester
Manchester M13 9PL, UK
tel. +44(0)161 306 6585; fax. +44(0)161 306 9361;
john.stevenson@manchester.ac.uk

3

Vincent wrote:

in a map composition I need to draw contours with two
particular
linestyles:
- a line bedecked with crosses: ----x----x----x----x----

I suspect for that you might have to use the v.lrs modules or
v.to.points to make points along the line at a regular interval,
then display them over the top with a vpoints command. Perhaps
there is another way though.

Hamish

4

Hi John,
thanks for the trick, I'll give it a try, though I need two black lines
with /transparency/ in between.

Vincent.

Le mardi 12 janvier 2010 à 10:10 +0000, John A Stevenson a écrit :

Vincent Bain wrote:
> Hello,
> in a map composition I need to draw contours with two particular
> linestyles:
> - a line bedecked with crosses: ----x----x----x----x----
> - a double line: =====================
>
Hi Vincent,

I have plotted a double line like this:

vlines my_lines
    color yellow
    width 1.5
    label Chirp lines
    lpos 4
    style 000111
end

vlines my_lines
    color black
    width 3
    label Chirp lines
    lpos 4
    style 000111
end

The top entry in the file plots on top in the map. This gives a black
dotted line with a yellow middle. Specifying the same legend position
recreates the pattern in the legend.

Later

John

5

Yes Hamish, this is what I was planning to do in the end.
If I go this way, I'll probably have to implement an 'angle' attribute
in order to align my point symbols on the line direction... Will give it
a try too,

thank you,
Vincent.

Le mardi 12 janvier 2010 à 02:57 -0800, Hamish a écrit :

Vincent wrote:
> in a map composition I need to draw contours with two
> particular
> linestyles:
> - a line bedecked with crosses: ----x----x----x----x----

I suspect for that you might have to use the v.lrs modules or
v.to.points to make points along the line at a regular interval,
then display them over the top with a vpoints command. Perhaps
there is another way though.

Hamish

6

Vincent:

I need two black lines with /transparency/ in between.

try the offset or coffset setting within the vlines instruction:

       offset (experimental) - offset for the vectors lines in pixels for plotting parallel
       lines in distance equal to offset (accepts positive or negative decimal points).
       Useful to print streets with several parallel lanes;

       coffset (experimental) - offset for the vectors lines. If coffset is used then off-
       set of line is equal to coffset * category value and offset is used in legend;

(I think that "pixels" should really say "points", but..)

Hamish