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7.22 World-wide seismicity the last 7 days

The next example uses the command-line tool wget to obtain a data file from a specified URL7.4. In the example script this line is commented out so the example will run even if you do not have wget (we use the supplied neic_quakes.d which normally would be created by wget); remove the comment to get the actual current seismicity plot using the live data. The main purpose of this script is not to show how to plot a map background and a few circles, but rather demonstrate how a map legend may be composed using the new tool pslegend. Some scripting is used to pull out information from the data file that is later used in the legend. The legend will normally have the email address of the script owner; here that command is commented out and the user is hardwired to ``GMT guru''. The USGS logo, taken from their web page and converted to a Sun rasterfile, is used to spice up the legend.

#    GMT Example 22  $Id: job22.csh,v 1.8 2004/09/29 05:29:16 pwessel Exp $
# Purpose:    Automatic map of last 7 days of world-wide seismicity
# GMT progs:    gmtset, pscoast, psxy, pslegend
# Unix progs:    cat, sed, awk, wget|cur

# Get the data (-q quietly) from USGS using the wget (comment out in case
# your system does not have wget or curl)

#wget -q -O neic_quakes.d
#curl -s >! neic_quakes.d

# Count the number of events (to be used in title later. one less due to header)

set n = `cat neic_quakes.d | wc -l`
@ n--

# Pull out the first and last timestamp to use in legend title

set first = `sed -n 2p neic_quakes.d | awk -F, '{printf "%s %s\n", $1, $2}'`
set last  = `sed -n '$p' neic_quakes.d | awk -F, '{printf "%s %s\n", $1, $2}'`

# Assign a string that contains the current user @ the current computer node.
# Note that two @@ is needed to print a single @ in pstext:

#set me = "$user@@`hostname`"
set me = "GMT guru @@ GMTbox"

# Create standard seismicity color table

cat << EOF >! neis.cpt
0    red    100    red
100    green    300    green
300    blue    10000    blue

# Start plotting. First lay down map, then plot quakes with size = magintude/50":

pscoast -Rg -JK180/9i -B45g30:."World-wide earthquake activity": -Gbrown -Slightblue \
  -Dc -A1000 -K -U/-0.75i/-2.5i/"Example 22 in Cookbook" -Y2.75i >!
awk -F, '{ print $4, $3, $6, $5*0.02}' neic_quakes.d \
    | psxy -R -JK -O -K -Cneis.cpt -Sci -Wthin -H >>

# Create legend input file for NEIS quake plot

cat << EOF >! neis.legend
H 16 1 $n events during $first to $last
D 0 1p
N 3
V 0 1p
S 0.1i c 0.1i red 0.25p 0.2i Shallow depth (0-100 km)
S 0.1i c 0.1i green 0.25p 0.2i Intermediate depth (100-300 km)
S 0.1i c 0.1i blue 0.25p 0.2i Very deep (> 300 km)
V 0 1p
D 0 1p
N 7
V 0 1p
S 0.1i c 0.06i - 0.25p 0.3i M 3
S 0.1i c 0.08i - 0.25p 0.3i M 4
S 0.1i c 0.10i - 0.25p 0.3i M 5
S 0.1i c 0.12i - 0.25p 0.3i M 6
S 0.1i c 0.14i - 0.25p 0.3i M 7
S 0.1i c 0.16i - 0.25p 0.3i M 8
S 0.1i c 0.18i - 0.25p 0.3i M 9
V 0 1p
D 0 1p
N 1

# Put together a reasonable legend text, and add logo and user's name:

cat << EOF >> neis.legend
T USGS/NEIS most recent earthquakes for the last seven days.  The data were
T obtained automatically from the USGS Earthquake Hazards Program page at
T @_http://neic/ @_.  Interested users may also receive email alerts
T from the USGS.
T This script can be called daily to update the latest information.
G 0.4i
# Add USGS logo
I USGS.ras 1i RT
G -0.3i
L 12 6 LB $me

# OK, now we can actually run pslegend.  We center the legend below the map.
# Trial and error shows that 1.7i is a good legend height:

pslegend -Dx4.5i/-0.4i/7i/1.7i/TC -Jx1i -R0/8/0/8 -O -F neis.legend -Glightyellow >>

# Clean up after ourselves:

\rm -f neis.* .gmtcommands4 .gmtdefaults4

Figure 7.23: World-wide seismicity the last 7 days.

The script produces the plot in Figure 7.23, giving the URL where these and similar data can be obtained.

next up previous contents index
Next: 7.23 All great-circle paths Up: 7. Cook-book Previous: 7.21 Time-series of RedHat   Contents   Index
Paul Wessel 2004-10-01