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Note: A new GRASS GIS stable version has been released: GRASS GIS 7.4, available here.
Updated manual page: here

PNG DISPLAY DRIVER

Table of contents

PNG display driver to create PNG, PPM, or BMP images.

DESCRIPTION

The PNG driver generates PNG, PPM, or BMP images from GRASS display commands. Per default PNG files are written with this driver. This driver is used by default if Cairo driver is not available.

USAGE

Environment variables

The PNG driver can be enabled by setting GRASS_RENDER_IMMEDIATE variable, eg.
export GRASS_RENDER_IMMEDIATE=png
Several environment variables affect the operation of the PNG driver:

Example

export GRASS_RENDER_IMMEDIATE=png
export GRASS_RENDER_TRUECOLOR=TRUE

g.region raster=elevation
d.rast elevation
d.vect roadsmajor color=red
This writes a file named map.png in your current directory.

NOTES

The PNG driver uses the libpng (see the libpng home page) and zlib (see the zlib home page), all which needs to be installed for the PNG driver to work (it's worth it).

The resolution of the output images is defined by current region extents. Use g.region -p to get the number of rows and cols and use the environment variables to set the image size. If you would like a larger image, multiply both rows and cols by the same whole number to preserve the aspect ratio.

Further PNG file processing (e.g. quantization to 1 bit for monochrome images) can be done with pnmquant of the netpbm tools.

SEE ALSO

Cairo driver, PS driver, HTML driver, variables

d.rast, d.vect, d.mon, d.erase, d.redraw

AUTHOR

Original version: Per Henrik Johansen <phj (at) norgit.no>
Rewritten by: Glynn Clements, 2003

Last changed: $Date: 2014-12-19 13:17:36 -0800 (Fri, 19 Dec 2014) $


Note: A new GRASS GIS stable version has been released: GRASS GIS 7.4, available here.
Updated manual page: here

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© 2003-2018 GRASS Development Team, GRASS GIS 7.2.4svn Reference Manual