[OSRS-PROJ] New projection routines??
Gerald I. Evenden
gerald.evenden at verizon.net
Sun Mar 9 16:44:47 EST 2003
The following is the bash script I use to generate most of the
pseudo cylindrical illustrations. The last bit is the control
string for 'gnuplot'. Procedure coast reads world coast line data,
passes it through a call to the PJ library and transfers the
resultant xy vectors to the scratch file. Procedure graticule
generates a graticule of constant lat-lon lines, passes ll data
though a call to PJ lib and concatinates the xy output to the
scratch file. Finally, the scratch file is passed to gnuplot which
outputs an eps.
First arg is projection name. A second arg contains any added
+operation details. None In this case.
Process is pretty speedy:
[gie at localhost figs]$ time ./proto times
# prototype for generating illustration
$BASE/$BIN/graticule $gratarg $proj +R=1 >data.dat
echo -e "\n" >>data.dat
zcat $COAST/world | \
$BASE/$BIN/coast $coastarg $proj +R=1 >>data.dat
set output "$1.eps"
set terminal postscript eps
set data style lines
set bmargin 0
set rmargin 0
set tmargin 0
set lmargin 0
The main reason that gnuplot files are longer than 'plotter'
output is each output vector element in gnuplot looks like
-36 224 V
-25 215 V
-18 416 V
whereas plotter would generate something like:
-36 224 -25 215 -18 416 V
That is, a long string of delta pairs before doing a plot command.
Gnuplot also has an overhead of spec'ing characters in the
preample that plotter did not but that is only a 1 or 2k
<blank>V per line takes a lot of bytes.
Gnuplot is fairly sophisticated, this job is pretty crude and
does not exercise the program. I'm mostly turning off options.
On Sun, 2003-03-09 at 13:47, Karl Swartz wrote:
> > But tell me of an alternative with a GNU license or equivalence.
> Good question. I don't really know of any, though I don't do much with
> > But the bottom line is this: it replicates the ps files that
> > are in the PROJ.4 pdfs and the ps files are only about 70% larger
> > that the ps files generated by my old 'plotter' program. Gnuplot
> > has a lot more flexibility than 'plotter'.
> Fascinating. I would have expected gnuplot to do a crude and cumbersome
> job at best. Would you mind sharing the commands you're using (and a
> bit of sample data) so this old dog can learn some new tricks? Thanks!
> -- Karl
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