Chris and Artem,
Thanks so much for the details.
This makes perfect sense now from my end. I was missing the
distinction between scale denominators and scale in the mapnik code.
The OGC 'Standard' pixel size in millimeters is exactly what Artem
used (in meters) here:
http://trac.mapnik.org/browser/trunk/src/scale_denominator.cpp#L37
Which I see defined in the OGC SLD Spec in Section '10.2 Scale
Selection' in the pdf here:
http://portal.opengeospatial.org/files/?artifact_id=1188
Thanks!
Dane
On Nov 26, 2008, at 4:14 AM, Christopher Schmidt wrote:
On Wed, Nov 26, 2008 at 09:57:21AM +0000, Artem Pavlenko wrote:
On 24 Nov 2008, at 18:47, Jay Douillard wrote:
I've added a page to the trac wiki around this topic
http://trac.mapnik.org/wiki/ScaleAndPpi
Please consider it a first draft!
Great, thanks Jay! Just to clarify, scale denominators (Layer and
Rule objects) are both using 'standard' pixel size. I think I got
these ideas from SLD spec. I'll need to check.
Yeah, this is 90.smethingsomething (*not* 92).
"The "standardized rendering pixel size" is defined to be 0.28mm
0.28mm
(millimeters). Frequently, the true pixel size of the final rendering
device is unknown in the web environment, and 0.28mm is a common
actual
size for contemporary video displays."
So, 1 dot /.011023 inches: 90.7142861 dpi.
Regards,
--
Christopher Schmidt
MetaCarta
_______________________________________________
Mapnik-users mailing list
[email protected]
https://lists.berlios.de/mailman/listinfo/mapnik-users
_______________________________________________
Mapnik-users mailing list
[email protected]
https://lists.berlios.de/mailman/listinfo/mapnik-users
