Generic Mapping Tools
(GMT)
Maps
Final script for Example 1
#!/bin/bash
psbasemap -R0/100/0/10 -JX5i/3i -Ba20g10/a2f1g2WSne \
-X2 -Y14 -K -P > plot.ps
sample1d -I1 << END |\
nawk '{print $1, sqrt($1)}' > input.dat
0
100
END
psxy input.dat -R -JX -W5t15_15:0 -K -O >> plot.ps
sample1d input.dat -I10 |\
psxy -R -JX -St0.5 -G255/0/0 -W5/0/255/0 -O >> plot.ps
gs plot.ps
Correction on the –W flag
psxy input.dat –R –JX -W5t15_15:0 -K –O >>
plot.ps
The –W command can be quite complicated and is specified in order
–W[width],[color],[texture]
In this example, the first 5 represents line width, the t signifies a
texture follows, the 15_15 specifies the dash and space width,
and the :0 specifies that a dash is used.
Alternately, -W5,0,15_15:- does the same thing.
Common command options on first, and
possibly subsequent, calls
• Need on all calls
-R Define region for plot – will need on first
call and at least “–R” on subsequent
-J Define projection for plot – will need this on
all calls if need to define region
Common command options on first, and
possibly subsequent, calls
• (Generally) Need on first call only
-B Borders -- annotation, frame, grid. Only
need on first (or a single) call.
-P Switch between landscape and portrait
modes
-X Shift X axis
-Y Shift Y axis
Common command options on first, and
possibly subsequent, calls.
• Need when needed.
-K Don’t close PostScript (showpage), use
when more will follow
•
need on all but last GMT call
-O Don’t initialize PostScript, use when
appending to pre-existing file
•
need on all but first GMT call
• use both –K and –O when putting a large number of
GMT call outputs together
Common command options on first, and
possibly subsequent, calls.
• Need when needed.
-V Verbose (prints out stuff to standard error
for user).
-H Header records (tells GMT to skip first H
lines of ascii input file)
GMT Defaults
 There are about 100 parameters which can be
adjusted individually to modify the appearance of
plots or affect the manipulation of data. Each as a
default value.
 GMT defaults are kept in a file called ~/.gmtdefaults4.
There are tons of them and you can find out what
they are and what the mean reading the man page
for gmtdefaults.
 When a program is run, it initializes all parameters to
the GMT defaults, then tries to open the file
.gmtdefaults4 in the current directory. If not found, it
will look for that file in a sub-directory ~/.gmt, and
finally in your home directory itself. If successful, the
program will read the contents and set the default
values to those provided in the file.
 To view your current gmtdefault settings
%gmtdefaults –L
 To view the list of options for each default parameter
%man gmtdefaults
Plotting Defaults
example of start of .gmtdefaults4
#
GMT-SYSTEM 4.2.1 Defaults file
#-------- Plot Media Parameters -PAGE_COLOR
PAGE_ORIENTATION
PAPER_MEDIA
= 255/255/255
= landscape
= letter
#--- Basemap Annotation Parameters -ANNOT_MIN_ANGLE
= 20
ANNOT_MIN_SPACING
=0
ANNOT_FONT_PRIMARY
ANNOT_FONT_SIZE
ANNOT_OFFSET_PRIMARY
= Helvetica
= 14p
= 0.075i
Changing the defaults
 You can edit your local copy of .gmtdefaults4 using
nedit or vim
 You can explicitly reset a default within a script using
the command gmtset
#!/bin/sh
gmtset PAPER_MEDIA letter MEASURE_UNIT cm
gmtset OUTPUT_DEGREE_FORMAT +D
gmtset PLOT_DEGREE_FORMAT +D
How about making pretty MAPS?
Map projections available in GMT
List of “standard”
command line
options.
The –J option sets
the “projection”
One has to look at
the man page for
each one as
“different things
vary”
pscoast -R-90/-70/0/20 -JM6i -P -B5g5 -G180/120/60 > map1.ps
“All” gmt programs
plot “maps”
through the
projection
command line
option or switch
(even the x-y plot).
pscoast -R-90/-70/0/20 -JM6i -P -B5g5 -G180/120/60 > map1.ps
All projections
give you two
selections for
specifying the
scale
(note GMT takes the mapmakers
attitude that a map has to have a
predetermined/known scale –
nicely filling the page does not
cut it.)
pscoast -R-90/-70/0/20 -JM6i -P -B5g5 -G180/120/60 > map1.ps
-Jmparameters
(Mercator [C]).
Specify one of:
-Jmscale
or -JMwidth
Give scale along
equator
(1:xxxx or UNIT/degree).
pscoast -R-90/-70/0/20 -JM6i -P -B5g5 -G180/120/60 > map1.ps
-Jmlon0/lat0/scale or
-JMlon0/lat0/width
Give central
meridian, standard
latitude and scale
along parallel
(1:xxxx or UNIT/degree, UNIT =
number inches or cms).
Mercator Projection:
One way to address plotting sphere on a
plane (which is whole ‘nother subject)
Conformal (maintains shapes)
Cylindrical projection
pscoast -R-130/-70/24/52 -JB-100/35/33/45/6i -B10g5:."Conic\
Projection": -N1/2p -N2/0.25p -A500 -G200 -W0.25p -P >! map.ps
Region is
“rectangle” on
the spherical
earth.
-N for
boundaries
(international,
US/Canadian/Mexican
state boundaries “built
in”)
, rivers.
pscoast -R-130/-70/24/52 -JB-100/35/33/45/6i -B10g5:."Conic\
Projection": -N1/2p -N2/0.25p -A500 -G200 -W0.25p -P >! map.ps
-A to get rid of
small
water/island
features
Albers
projection (b/B)
– need to know
something
(center and
standard
pscoast -R-130/-70/24/52 -JB-100/35/33/45/6i -B10g5:."Conic\
Projection”: -N1/2p -N2/0.25p -A500 -G200 -W0.25p -P >! map.ps
-Jblon0/lat0/lat1/lat2/scale or -JBlon0/lat0/lat1/lat2/width
Albers - Give projection center, two
standard parallels, and scale (1:xxxx or UNIT/degree).
Albers
Also conformal (maintains/conserves shape)
Conical projection
pscoast -R0/360/-90/90 -JG280/30/6i -Bg30/g15 -Dc -A5000 \
-G255/255/255 -S150/50/150 -P >! map.ps
azimuthal
Orthographic
projection (g/G)
mimics looking at
earth from
infinite distance.
pscoast -R0/360/-90/90 -JG280/30/6i -Bg30/g15 -Dc -A5000 \
-G255/255/255 -S150/50/150 -P >! map.ps
New option
-Dc
Controls resolution
of coastline
f full
h high
l low
c crude
Helps manage file
sizes.
Example 2
Simple
location map
with focal
mechanisms
 gmtset: To change individual GMT default parameters
 pscoast: Plot coastlines, filled continents, rivers, and
political borders
 psxy: Plot symbols, polygons, and lines in 2-D
 pstext: Plot text strings
 psmeca: Plot focal mechanisms on maps
#!/bin/sh
###Create a basemap for the Sumatra-Andaman Island region
#Set global variables
Plots=../BasicInfo
CPT=/usr/local/GMT4.2.0/share/cpt
LATMIN=-6.2
LATMAX=16
LONMIN=90
LONMAX=106
OUTFILE=$0.ps
#What does the $0 signify on this line?
#Explicitly set some GMT default values
gmtset MEASURE_UNIT cm
ANOT_FONT_SIZE 12
gmtset BASEMAP_TYPE fancy
LABEL_FONT_SIZE 12
#Map
# Create the basic basemap using GMT coastline data
pscoast -JM15 -R$LONMIN/$LONMAX/$LATMIN/$LATMAX -Ba2f1WNes -Y5 -X3 -K -P \
-Dh -A100 -N1 -W1 -G155 > $OUTFILE
•
•
•
•
-D Selects the resolution of the data set ((f)ull, (h)igh, (i)ntermediate, (l)ow, (c)rude)
-A Features with an area smaller than min_area in km^2
-W and –G Control the fill color and line color of the land regions
-N Plots political boundaries. 1 is for national boundaries, 2 is for states in the Americas
#Plot basic tectonic information, including subduction zones and volcanoes
psxy $Plots/trench.right.gmt -R -JM -M -W5/0 -Sf0.3i/0.08irt -G0 -O -K >> $OUTFILE
psxy $Plots/trench.left.gmt -R -JM -M -W5/0 -Sf0.3i/0.08ilt -G0 -O -K >> $OUTFILE
psxy $Plots/trench.other.gmt -R -JM -M -Wt30_30:1p5/0 -O -K >> $OUTFILE
psxy $Plots/transform.gmt -R -JM -M -Wt10_10:1p5/0 -O -K >> $OUTFILE
psxy $Plots/ridge.gmt -R -JM -M -W1/0 -O -K >> $OUTFILE
psxy $Plots/volcanoes.simkin+siebert.gmt -R -JM -St.35 -W1/0 -G0 -O -K >> $OUTFILE
• -M Multiple segment file. Segments are separated by a record whose first character is
flag. [Default is '>']. Example of trench.right.gmt
>
92.278 6.948
91.903 7.663
>
#Information for the 2004 Sumatra event
awk '{print $7, $6, $9/30}' $Plots/122604_032705.pde |\ #prints lat, lon,mag/30
psxy -R -JM -Sc -W1/0 -G255/255/100 -O -K >> $OUTFILE
• When no value is specified on the –S flag (ie 0.20), then the size of the circle (denoted by
the c) is controlled by the third column of info sent to the psxy command.
So we are scaling the circle size by what earthquake parameter in this example?
• Example of 122604_032705.pde from http://neic.usgs.gov/neis/epic/epic_rect.html
PDE-W 2004 12 26 005853.45 3.30 95.98 30 9.00 MwHRV 9C M STS...M
PDE-W 2004 12 26 011710.33 4.94 94.27 30 5.50 mb GS .. . .......
psxy -R -JM -Sa.89 -W1/0 -G255/255/0 -: -O -K << END >> $OUTFILE
3.3 95.98
END
• -Sa creates a star
• -: indicates that the data is in y-x format rather than x-y format. This is useful because we
speak of earthquakes in terms of latitude (y) and longitude (x) and therefore tend to write
geographic coordinates in this order as well.
#Global CMT solutions for events above Mw ~6.6
psmeca -R -JM -Sm0.5 -G255/255/100 -T -O -K << END >> $OUTFILE
#lon lat depth mrr mtt mpp mrt mrp mtp iexp name
94.26 3.09 29 1.04 -0.43 -0.61 2.98 -2.40 0.43 29 X Y 122604A
92.79 6.61 14 5.26 -0.84 -4.41 3.95 -2.91 2.10 26 X Y 122604B
92.45 8.58 12 0.94 -0.12 -0.81 0.02 -0.27 0.32 26 X Y 122604C
92.20 4.99 12 -0.02 -0.64 0.66 -0.11 -0.16 -0.80 26 X Y 010105A
95.38 2.84 12 0.26 -0.17 -0.09 0.90 -0.91 0.16 26 X Y 022605A
END
• psmeca creates lower hemisphere projections, aka beachballs. It is a rather complicated
little command.
• -S Selects the meaning of the columns in the data file.
• -Sa Focal mechanisms in Aki and Richard convention.
• -Sc Focal mechanisms in Harvard CMT convention.
• -Sm Seismic moment tensor (Harvard CMT, with zero trace).
•-Sd plot only the double couple part of moment tensor.
•-Sz plot anisotropic part of moment tensor (zero trace).
• http://www.globalcmt.org/CMTsearch.html
• -Sp Focal mechanisms given with partial data on both planes.
• -Sx Principal axis.
• -G Controls fill of the compressive quadrant of the moment tensor
• -T Plots the nodal planes
pstext -R -JM -: -O << END >> $OUTFILE
-3.5 90.5 14 0 0 0 Yellow: 2004 Mw 9.2 series
-5.75 90.5 14 0 0 0 CMT solutions for Mw >= 6.6
END
• format is x, y, size, angle, font#, justify, text
• %pstext –L will tell you the font # and font name
• you can use [T|M|B][L|C|R] to specify justification
(top/middle/bottom/left/center/right)
gs $OUTFILE #gs indicates ghostscript
if you are using vim to edit this script
:!script.gmt will run the script, open the
resulting file using gs, and you can see
what you have done. If you don’t like it,
type quit, and continue editing the file.
nawk commands as input to GMT
nawk '{print $9, $8, $11}' EBH.HDF
You can put this into GMT several ways
If this is the only file you want to plot – this
would work
nawk '{print $9, $8, $11}' EBH.HDF | pxsy …
If you had a number of files that needed
conversion you could do it this way (only
need one psxy call)
psxy … << END …
…
`nawk '{print $9, $8, $11}' EBH.HDF`
…
END
Converting each file on the fly.
If you want to do the same thing to a list of
files
filelist=“$SAMDATA/eq-rupt-1995.dat $DEM/eq-rupt-1960.dat”
for FILE in $filelist
do
psxy -R -$PROJ$SCALE -M$ -: $CONTINUE -W$LINETHICK/$PURPLE $FILE \
$VBSE >> $OUTPUTFILE
done
Other ways to make list
(notice the different kinds of quotes: “,’ and `)
filelist=`ls -1 $ROOT/dem/topocontours/andes_3000_*`
contourlist=‘1 2 3 4’
Some other nawk tricks – doing math and
passing variables to nawk (quote heaven)
SCALE=`echo $STNDTMLON | \
nawk ‘{print ($1>=0?$1:360+$1)”/”’${jTRESCALE}_1’*’$FACTOR’}’ `