Comments on: Plotting the world revisited

By: Ig77

Ig77 — Wed, 29 Dec 2021 17:31:46 +0000

Very Interesting.
I have a further question. I would display satellite tracks with lines (not points) overplotted on earthmap, how I can avoid the -180 180 jump in longitude?
Thank you

By: Little Orc

Little Orc — Tue, 24 Sep 2019 17:50:17 +0000

OMG, I live in Capri island and the 10m map just doesn’t feature it.
(BTW Ischia is there).

By: Pablo

Pablo — Fri, 06 Apr 2018 11:12:40 +0000

Hi, I have a matrix of numbers which correspond to pixels in an image. The file is in

https://www.dropbox.com/s/kkklktk82nvd20b/pher-of-1365.txt?dl=0

I have made a heatmap with them

set encoding iso_8859_1
# set terminal postscript eps enhanced color “Helvetica” 16 #size 3.5in,3in
set term postscript eps enhanced color size 4.7in,4in

# WORKS 1 Density
set xlabel “longitude”
set ylabel “latitude”
set output “test0.eps”
set size square
set title “Pher” font “Helvetica, 16”
# format the lateral bar
set format cb “%2.0t{/Symbol \327}10^{%L}”
set autoscale fix
set key
unset xtics
unset ytics
set yrange [:] reverse
set view map
splot ‘pher-of-1365.txt’ matrix with image

this image correspond with streets of a city with a squared area of N, S, E, W each 525 m from location point 51.05660 N, 3.721500 E.
I would like to plot a map of this place overlayed with my file which should match with the streets.

Any idea of how I could compound an image like this or how I could get a squared map of the coordinates above and then overlay my image on it?

By: Gianni

Gianni — Wed, 31 Jan 2018 17:45:02 +0000

I am sorry but the reported script was somehow truncated !!! Sorry for that...

# Rounding number to next integer in admin mode (0.5 = goUp)
round(x) = x-floor(x)180.0 ? x : round2(x+y,roundDec)180.0 ? round2(x+y-360.0,roundDec) : round2(x+y,roundDec)
# The following is generating only one spurious line on antarctica
shiftVal=-11.500000
# Plotting using shifted latitude
plot 'world_110m.txt' using (shiftMap($1,shiftVal)):($2) with lines linestyle 1

Hope is more clear now...

By: Gianni

Gianni — Wed, 31 Jan 2018 17:41:06 +0000

I've improved my solution adding a rounding function. Now the script is working properly with shifting =0.0 or >180.0 or <-180.0. In all other cases one or more spurious lines are included into the generated chart. Latest script is the following:

reset
set terminal pngcairo size 1920,1184 enhanced font 'Verdana,12'
set output 'w2d.png'
set style line 1 linecolor rgb 'black' linetype 1 linewidth 2
unset key
set border 0
unset tics
set encoding utf8
# Rounding number to next integer in admin mode (0.5 = goUp)
round(x) = x-floor(x)180.0 ? x : round2(x+y,roundDec)180.0 ? round2(x+y-360.0,roundDec) : round2(x+y,roundDec)
# Centered as default: it works!
# shiftVal=0.000000
# Centered on Rome
# shiftVal=-12.482778
# The following is generating only one spurious line on antarctica
shiftVal=-11.500000
# Centered on USA
# shiftVal=100.000000
# Centered on left extreme
# shiftVal=180.000000
# Centered on right extreme
# shiftVal=-180.000000
# Forcing an error: it works!
# shiftVal=-181.000000
# Base plotting
# plot 'world_110m.txt' using 1:2 with lines linestyle 1
# Plotting using shifted latitude
plot 'world_110m.txt' using (shiftMap($1,shiftVal)):($2) with lines linestyle 1

Any hint on how to solve this issue?

By: Gianni

Gianni — Tue, 30 Jan 2018 05:46:31 +0000

Hi all, following my previous request I've tried to put together the following script:

reset
set terminal pngcairo size 1920,1184 enhanced font 'Verdana,12'
set output 'w2d.png'
set style line 1 linecolor rgb 'black' linetype 1 linewidth 2
unset key
set border 0
unset tics
set encoding utf8
# shiftMap(currentLatitude, shiftVal) function definition
shiftMap(x,y) = abs(y)>180.0 ? x : (x+y)180.0 ? (x+y-360.0) : (x+y)
# Centered as usual
# shiftVal=0.0
# Centered on Rome
# shiftVal=-12.482778
# Cenetered on USA
shiftVal=90
# Plotting using shifted latitude
plot 'world_110m.txt' using (shiftMap($1,shiftVal)):($2) with lines linestyle 1

It works but output is always including some wrong lines crossing the whole chart. Any hint on how to solve this issue?

By: Gianni

Gianni — Sun, 28 Jan 2018 15:44:38 +0000

Hi All,
following all valuable examples available on this site I’ve successfully plot the world map, either in 2d or in 3d. While plotting 3d world map using “set view” command I was able to center the map on a specific region; is there available an equivalent command to center a 2d world map on a specific meridian position? In other words: is it possible to have Americas in the central part of the map with Europe on the right and Japan on the left?
Thanks in advance for any input!

By: nohup

nohup — Thu, 31 Mar 2016 15:15:05 +0000

I don’t know

By: nohup

nohup — Thu, 17 Mar 2016 18:10:57 +0000

How to plot the map of Earth in 3D format with points only, without colorized surface??

By: Valerio Schiavoni

Valerio Schiavoni — Wed, 21 Oct 2015 23:52:43 +0000

I wonder if it is possible to 1) draw the map of the world WITH country/border nations, including USA states, and 2) highlight some of those countries with different (filling) color.
Initially the areas inside the borders can be white.

Has anyone ever tried something like this with Gnuplot ?