[GRASS-user] editing grass postscript maps

Glynn Clements glynn at gclements.plus.com
Wed May 16 20:13:47 EDT 2007


Tyler Smith wrote:

> The actual size of the files became an issue. Each of the eight maps
> was 100MB,

Ouch.

Next time, you might want to use "g.region res=" to reduce the size of
the raster data. 100MB is ~16 million pixels @ 6 bytes/pixel (RRGGBB).

Looking at the "paper" command:

  width 2.73 inches
  height 1.75 inches

2.73 * 1.75 = 4.7775 sq.in.
100e6 / 6 = 16666667 pixels
16666667 / 4.7775 = 3488575 pixels/sq.in.
sqrt(3488575) = 1868 pixels/in

Even if the printer does 2400 DPI, the halftone resolution is going to
be a fraction of that, so you could reduce the resolution
substantially without seeing any noticable difference.

I doubt that there's much point in going above 300 DPI (around 1/6th
of what you appear to have) for a raster; 2.73" * 1.75" @ 300 DPI
would be 819 * 525.

-- 
Glynn Clements <glynn at gclements.plus.com>




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