Greetings
I’m using r.out.png to generate PNG files from a small patch (like 6x15 pixels) but I’m obtaining a really small PNG file. Sicne I want to display it a little bit bigger in a website I need to “create a bigger (in size) PNG”. What can I do to do this?
One idea was to rescale it in a image processing software but I get a low quality image
Is there any solution by using grass?
Thanks
Luisa
You can simply increase the resolution of your
current working region. Then you will get more
cells (and a bigger image) but exactly the same
information.
Ben
On 11/03/2011 01:16 PM, Luisa Peña wrote:
Greetings
I'm using r.out.png to generate PNG files from a small patch (like 6x15
pixels) but I'm obtaining a really small PNG file. Sicne I want to
display it a little bit bigger in a website I need to "create a bigger
(in size) PNG". What can I do to do this?
One idea was to rescale it in a image processing software but I get a
low quality image
Is there any solution by using grass?
Thanks
Luisa_______________________________________________
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--
Benjamin Ducke
{*} Geospatial Consultant
{*} GIS Developer
benducke@fastmail.fm
Luisa said:
I’m using r.out.png to generate PNG files from a small patch (like 6x15
pixels) but I’m obtaining a really small PNG file. Sicne I want to
display it a little bit bigger in a website I need to “create a bigger
(in size) PNG”. What can I do to do this?
Ben said:
You can simply increase the resolution of your
current working region. Then you will get more
cells (and a bigger image) but exactly the same
information.
Or I guess you could export it with a larger number of pixels by setting some environment variables.
export GRASS_WIDTH=
export GRASS_HEIGHT=
Cheers,
Marcello.
Marcello Gorini wrote:
>>I'm using r.out.png to generate PNG files from a small patch (like 6x15
>>pixels) but I'm obtaining a really small PNG file. Sicne I want to
>>display it a little bit bigger in a website I need to "create a bigger
>>(in size) PNG". What can I do to do this?Ben said:
>You can simply increase the resolution of your
>current working region. Then you will get more
>cells (and a bigger image) but exactly the same
>information.Or I guess you could export it with a larger number of pixels by setting
some environment variables.export GRASS_WIDTH=
export GRASS_HEIGHT=
Those will affect the size of images generated by d.* commands using
the PNG driver. They won't have any effect upon the images generated
by d.out.png.
--
Glynn Clements <glynn@gclements.plus.com>
Glynn Clements wrote:
> export GRASS_WIDTH=
> export GRASS_HEIGHT=Those will affect the size of images generated by d.* commands using
the PNG driver. They won't have any effect upon the images generated
by d.out.png.
Oops; I meant r.out.png, not d.out.png.
--
Glynn Clements <glynn@gclements.plus.com>
Marcello Gorini wrote:
Or I guess you could export it with a larger number of pixels by setting
some environment variables.export GRASS_WIDTH=
export GRASS_HEIGHT=
Glynn:
Those will affect the size of images generated by d.* commands using
the PNG driver. They won’t have any effect upon the images generated
by d.out.png.
True, my bad, sorry. Once again, I am so used to use “d.mon star=PNG etc…” that I bypassed the r.out.png part of her e-mail 
Hamish:
The book is good, d.out.file is simply using the PNG driver internally.
Oh, no, the book is not good… it is awesome! It has got me going really fast in the beggining and still helps me a lot. The most usefull book I have by far!
n.b. I typically use this when I want to show multiple overlaid rasters
in ps.map, which can only display one raster at a time. d.out.file format=
geotiff then r.in.gdal + r.composite (or ps.map’s rgb instruction).
Thanks for the tip!
Cheers,
Marcello.