[Tilecache] [Mapnik-users] png256 transparency and nodata with raster, mapnik

Dane Springmeyer blake at hailmail.net
Thu Jan 29 14:40:01 EST 2009


Matt,

Mapnik's png256 format does not support opacity AFAIK.

Could you file a trac ticket?

Dane



On Jan 29, 2009, at 11:21 AM, Matt Bartolome <mattxbart at gmail.com>  
wrote:

> Hi, this is a tilecache + mapnik question.
>
> I'm wondering if it is possible to set a nodata value to transparent
> when rendering raster data with png256 in tilecache. I wanted to use
> the png256 extension in my tilecache.cfg but when the bounding box
> exceeds the raster I get a black boundary for the missing data. With
> the default extension (regular png) in tilecache it is transparent so
> the black doesn't show up however each tile can be upwards of 200K,
> which I am currently using pngnq to compress. It would be nice if it
> could be accomplished in one swoop.
>
> -Matt
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> Mapnik-users at lists.berlios.de
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