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+#======================================================================
+#                    L I B G M T . P L 
+#                    doc: Sun Jun 14 13:45:47 2015
+#                    dlm: Sun Sep 27 09:23:46 2015
+#                    (c) 2015 A.M. Thurnherr
+#                    uE-Info: 45 10 NIL 0 0 72 2 2 4 NIL ofnI
+#======================================================================
+
+# perl implementation of /Data/Makefiles/Makefile.GMT
+
+#----------------------------------------------------------------------
+# USAGE
+#----------------------------------------------------------------------
+#
+# Basic Example
+# -------------
+# GMT_begin('temp_prof.ps','-JX10/-10','-R0/30/0/5000');
+# GMT_psxy('-W1,red');
+# print(GMT "$temp $depth\n");
+# GMT_end('-Ba5f1:"Temperature [degC]":/a500f100:"Depth [m]":WeSn');
+#
+# Other GMT Utilities
+# -------------------
+# GMT_pstext(<opts>)			x y size angle fontno justify(ML,BC,TR,...) "text"
+# GMT_psbasemap(<opts>)			often implies GMT_end() w/o args
+# GMT_psscale(<opts>)			scale bar
+#
+# Other Extensions
+# ----------------
+# GMT_unitcoords();				afterwards, x and y range from 0 to 1; useful for legends
+# GMT_setR('-R0/1/0/1')			subsequent GMT utilities use this ROI
+# GMT_setJ('-JX10/-1-')			subsequent GMT utilities use this projection
+# GMT_setAnnotFontSize(7)		set primary annotation font size
+#
+#----------------------------------------------------------------------
+
+# HISTORY:
+#	Jun 14, 2015: - created
+#	Jun 16, 2015: - BUG: forgot to return to PWD
+#	Jun 18, 2015: - added $DEBUG
+#	Jul 26, 2015: - added usage documentation
+#				  - simplified GMT_unitcoords()
+#	Jul 28, 2015: - added GMT_setAnnotFontSize(), GMT_psscale()
+
+$DEBUG = 0;
+
+#----------------------------------------------------------------------
+# Library
+#----------------------------------------------------------------------
+
+my($GMT_plotfile);
+my($GMT_J);
+my($GMT_R);
+
+sub GMT_setR($) { ($GMT_R) = @_; }						# (re-)define -R
+sub GMT_setJ($) { ($GMT_J) = @_; }						# (re-)define -J
+
+sub GMT_spawn($)										# spawn GMT command in temp dir
+{
+	my($cmd) = @_;
+	close(GMT);
+	chdir("/tmp/antsGMT.$$") ||
+		croak("/tmp/antsGMT.$$: $!\n");
+	print(STDERR "$cmd\n") if ($DEBUG);
+	open(GMT,$cmd) || croak("$cmd: $!\n");
+	chdir("$ENV{PWD}") ||
+		croak("$ENV{PWD}: $!\n");
+}
+
+sub GMT_set(@)											# set GMT defaults
+{
+	GMT_spawn("| gmtset @_");
+}
+
+#----------------------------------------------------------------------
+# GMT_begin(plot_file,J,R,extra_opts),
+#	e.g. GMT_begin('temp_prof.ps','-JX10/-10','-R0/30/0/5000');
+#		1) create temp directory
+#		2) set GMT defaults
+#		3) create plot file with empty psxy
+#----------------------------------------------------------------------
+
+my($LABEL_FONT_SIZE) = 14 unless defined($LABEL_FONT_SIZE);
+my($ANNOT_FONT_SIZE) = 14 unless defined($ANNOT_FONT_SIZE);
+
+sub GMT_begin(@)
+{
+	my($pfn,$J,$R,$extra) = @_;
+	mkdir("/tmp/antsGMT.$$");
+	chdir("/tmp/antsGMT.$$") ||
+		croak("/tmp/antsGMT.$$: $!\n");
+	system("rm -f .gmt*
+			gmtset MEASURE_UNIT cm PAPER_MEDIA letter \\
+			       LABEL_FONT_SIZE ${LABEL_FONT_SIZE} \\
+	               ANNOT_FONT_SIZE_PRIMARY ${ANNOT_FONT_SIZE} \\
+	               WANT_EURO_FONT true \\
+	               PLOT_DEGREE_FORMAT ddd:mm:ssF") &&
+		croak("gmtset failed\n");
+	$GMT_plotfile = "$ENV{PWD}/$pfn";
+	GMT_setJ($J); GMT_setR($R);
+	GMT_spawn("| psxy -K $J $R $extra > $GMT_plotfile");
+	close(GMT);
+}
+
+sub GMT_setAnnotFontSize($)
+{
+	GMT_set("ANNOT_FONT_SIZE_PRIMARY $_[0]");
+}
+
+#----------------------------------------------------------------------
+# GMT_end(B)
+#	1) chdir to temp-dir
+#	2) psbasemap w/o -K
+#	3) close GMT file
+#	4) remove GMT temp dir
+#----------------------------------------------------------------------
+
+sub GMT_end(@)
+{
+	my($opt) = @_;
+	$opt = '-G' unless defined($opt);
+	
+	GMT_spawn("| psbasemap -O $GMT_J $GMT_R $opt >> $GMT_plotfile");
+	close(GMT);
+	chdir("$ENV{PWD}") || croak("ENV{PWD}: $!\n");
+	system("rm -rf /tmp/antsGMT.$$") &&
+		croak("Offending command: rm -rf /tmp/antsGMT.$$\n");
+}
+
+#----------------------------------------------------------------------
+# GMT_unitcoords()
+#	- set unit coordinate system
+#----------------------------------------------------------------------
+
+sub GMT_unitcoords()
+{
+	GMT_setR('-R0/1/0/1');
+}
+
+sub GMT_unitcoords_logscale()
+{
+	($jx,$jy) = ($GMT_J =~ m{-J.-?(\d+)[a-z]*/-?(\d+)});
+	if (defined($jy)) {
+		GMT_setJ("-JX$jx/$jy");
+	} else {
+		($jx) = ($GMT_J =~ m{-J.-?(\d+)});
+		if (defined($jx)) {
+			GMT_setJ("-JX$jx");
+		} else {
+			croak("cannot decode $GMT_J ($jx,$jy)");
+		}
+	}
+	GMT_setR('-R0/1/0/1');
+#	GMT_spawn("| psxy -O -K $GMT_J $GMT_R >> $GMT_plotfile");
+#	close(GMT);
+}
+
+#----------------------------------------------------------------------
+# GMT_psxy(opts)
+# GMT_psbasemap(opts)
+# GMT_pstext(opts)
+# GMT_psscale(opts)
+#----------------------------------------------------------------------
+
+sub GMT_psxy(@)
+{
+	my($opts) = @_;
+	GMT_spawn("| psxy -O -K $GMT_J $GMT_R $opts >> $GMT_plotfile");
+}
+
+sub GMT_psbasemap(@)
+{
+	my($opts) = @_;
+	GMT_spawn("| psbasemap -O -K $GMT_J $GMT_R $opts >> $GMT_plotfile");
+}
+
+sub GMT_pstext(@)
+{
+	my($opts) = @_;
+	GMT_spawn("| pstext -O -K $GMT_J $GMT_R $opts >> $GMT_plotfile");
+}
+
+sub GMT_psscale(@)
+{
+	my($opts) = @_;
+	GMT_spawn("| psscale -O -K $opts >> $GMT_plotfile");
+}
+
+1;