[Geoserver-users] high quality printing

hi,

I need to create maps of quality for publication in journals. So, these
images are not for be seen in browser but to be stored and reused later in
PDFs or saved as images.
The requirements seem to be:

If CMYK minimum resolution 300dpi (for raster only) and 400dpi (if vector
data)
For print quality RGB and 150dpi should be fine ?

From my ignorance in these issues, these basic questions arise:

-can we determine the precision (dpi) of the image to get from Geoserver? I
supose that as default is 72-91 dpi (browser max resolution), so from this
low quality image cannot be generated a better one (even if we process it
server-side), suppose. If it's possible, there is some docs over there?

-Geoserver served images are always RGB? I say that because screen computers
always use RGB but maybe we can ask geoserver directly CMYK if we want to
store the data without showing on the screen (just save as jpeg or png...).

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GeoServer accepts a bounding box and pixel height / width, it doesn't care about resolution per se. You can request a 2000x2000 pixel image (watch memory usage), save it to disk, open it in GIMP or Photoshop and then print out as a 1inchx1inch image -> 2000 dpi. Some image formats do support storing a suggested resolution, I don't think we provide a way of customizing that, and it's easy to override when you print anyway.

I believe all our outputformats are RGB.

-Arne

pere roca wrote:

hi,

I need to create maps of quality for publication in journals. So, these
images are not for be seen in browser but to be stored and reused later in
PDFs or saved as images.
The requirements seem to be:

If CMYK minimum resolution 300dpi (for raster only) and 400dpi (if vector
data)
For print quality RGB and 150dpi should be fine ?

>From my ignorance in these issues, these basic questions arise:

-can we determine the precision (dpi) of the image to get from Geoserver? I
supose that as default is 72-91 dpi (browser max resolution), so from this
low quality image cannot be generated a better one (even if we process it
server-side), suppose. If it's possible, there is some docs over there?

-Geoserver served images are always RGB? I say that because screen computers
always use RGB but maybe we can ask geoserver directly CMYK if we want to
store the data without showing on the screen (just save as jpeg or png...).

  dear Arne,

  where can I configure the pixel height/width? I suppose that if I change
these parameters it will affect the rendering of all the layers I request
from now on... I mean, I only want high resolution when saving images, not
for visualizing in my webapp (running with the same geoserver). There is
some parameter, a "flag" to distinguish these different actions (different
resolutions required). If it's a GetMap request I'm afraid not... some other
way? the same applies for memory usage. I'm afraid I should install two
geoservers (one for saving images another for displaying in browser).

  thanks,

  Pere Roca
  EDIT project (http://edit.csic.es/edit_geo/prototype/edit.html)

Arne Kepp-2 wrote:

GeoServer accepts a bounding box and pixel height / width, it doesn't
care about resolution per se. You can request a 2000x2000 pixel image
(watch memory usage), save it to disk, open it in GIMP or Photoshop and
then print out as a 1inchx1inch image -> 2000 dpi. Some image formats do
support storing a suggested resolution, I don't think we provide a way
of customizing that, and it's easy to override when you print anyway.

I believe all our outputformats are RGB.

-Arne

pere roca wrote:

hi,

I need to create maps of quality for publication in journals. So, these
images are not for be seen in browser but to be stored and reused later
in
PDFs or saved as images.
The requirements seem to be:

If CMYK minimum resolution 300dpi (for raster only) and 400dpi (if vector
data)
For print quality RGB and 150dpi should be fine ?

>From my ignorance in these issues, these basic questions arise:

-can we determine the precision (dpi) of the image to get from Geoserver?
I
supose that as default is 72-91 dpi (browser max resolution), so from
this
low quality image cannot be generated a better one (even if we process it
server-side), suppose. If it's possible, there is some docs over there?

-Geoserver served images are always RGB? I say that because screen
computers
always use RGB but maybe we can ask geoserver directly CMYK if we want to
store the data without showing on the screen (just save as jpeg or
png...).

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Hi Pere,

The height and width parameters are sent with every WMS request. If you are using openlayers you can right click on the map, say view image (Firefox) and then see the parameters (including width and height) in the URL.

Unfortunately, after sleeping on it I realized my answer was a bit naive :frowning: Text and placemarks will not be scaled up when you make such a request, so you would also have to modify your SLDs to compensate for this (ie. text should probably be 120 pixels instead of 12 etc, the same for border widths).

-Arne

pere roca wrote:

  dear Arne,

  where can I configure the pixel height/width? I suppose that if I change
these parameters it will affect the rendering of all the layers I request
from now on... I mean, I only want high resolution when saving images, not
for visualizing in my webapp (running with the same geoserver). There is
some parameter, a "flag" to distinguish these different actions (different
resolutions required). If it's a GetMap request I'm afraid not... some other
way? the same applies for memory usage. I'm afraid I should install two
geoservers (one for saving images another for displaying in browser).

  thanks,

  Pere Roca
  EDIT project (http://edit.csic.es/edit_geo/prototype/edit.html)

Arne Kepp-2 wrote:
  

GeoServer accepts a bounding box and pixel height / width, it doesn't care about resolution per se. You can request a 2000x2000 pixel image (watch memory usage), save it to disk, open it in GIMP or Photoshop and then print out as a 1inchx1inch image -> 2000 dpi. Some image formats do support storing a suggested resolution, I don't think we provide a way of customizing that, and it's easy to override when you print anyway.

I believe all our outputformats are RGB.

-Arne

pere roca wrote:
    

hi,

I need to create maps of quality for publication in journals. So, these
images are not for be seen in browser but to be stored and reused later
in
PDFs or saved as images.
The requirements seem to be:

If CMYK minimum resolution 300dpi (for raster only) and 400dpi (if vector
data)
For print quality RGB and 150dpi should be fine ?

>From my ignorance in these issues, these basic questions arise:

-can we determine the precision (dpi) of the image to get from Geoserver?
I
supose that as default is 72-91 dpi (browser max resolution), so from
this
low quality image cannot be generated a better one (even if we process it
server-side), suppose. If it's possible, there is some docs over there?

-Geoserver served images are always RGB? I say that because screen
computers
always use RGB but maybe we can ask geoserver directly CMYK if we want to
store the data without showing on the screen (just save as jpeg or
png...).

-------------------------------------------------------------------------
This SF.Net email is sponsored by the Moblin Your Move Developer's
challenge
Build the coolest Linux based applications with Moblin SDK & win great
prizes
Grand prize is a trip for two to an Open Source event anywhere in the
world
http://moblin-contest.org/redirect.php?banner_id=100&url=/
_______________________________________________
Geoserver-users mailing list
Geoserver-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/geoserver-users

pere roca ha scritto:

  dear Arne,

  where can I configure the pixel height/width? I suppose that if I change
these parameters it will affect the rendering of all the layers I request
from now on... I mean, I only want high resolution when saving images, not
for visualizing in my webapp (running with the same geoserver). There is
some parameter, a "flag" to distinguish these different actions (different
resolutions required). If it's a GetMap request I'm afraid not... some other
way? the same applies for memory usage. I'm afraid I should install two
geoservers (one for saving images another for displaying in browser).

There is no way to specify the pixel size. Trying to work around by providing bigger height/width has the following disadvantages:
- it does change the scale of the map as computed by the WMS standard
   rules, meaning a different rendering might trigger if the SLD is using
   scale dependend rules
- as Arne noted, it does not make fonts bigger, or line width bigger,
   and so on.

Adding a parameter to specify the DPI is possible, that would be used
as a correction factor when computing the scale and the size of all
SLD elements specifyied in pixels, but it's no picnic, that would require making lots of changes in the renderer code, it would also
make the code very ugly and harder to maintain.

GeoServer WMS can output PDF directly, that one will be mostly vector
based, so it should be resolution independent. Unfortunately the
size of the lines and so on will be a bit arbitrary, since SLD allows
only sizing in pixels, and in the PDF output that does not make
much sense. But it's worth a try.

Cheers
Andrea