[OSM-dev] New t at h client with multi-layer support

Frederik Ramm frederik at remote.org
Thu Apr 5 07:48:43 BST 2007

Apologies if this is a duplicate, I meant to send it yesterday night but 
somehow it doesn't seem to have come through.



    I've just commited to SVN a new t at h client which supports rendering
multiple layers from one downloaded data set.

It is currently configured to run the default (old "basemap") and
maplint layers but I expect that 80n will soon add the bicycle/"outdoor"
layer he has been preparing.

The layer stuff is controlled from a new config file named, uhm,

I hope that some of you "early adopters" find the time to download the
new client and test it. If you want it to render maplint ONLY, simply
say "Layers=maplint" in layers.conf. This is what I just did for the
whole of London; maplint tiles should be visible there now. There was
a problem where node duplication would occur when a tile was
downloaded in multiple stripes and concatenated; this prompted me to
re-write the concatenation code - in typical "parse XML with regexes"
fashion, but if someone wants to come up with an XSLT based solution
for that, feel free to change it.

When playing around with layers, please keep in mind that it makes no
sense to upload layers for which the server is not configured - so if
you want your very special type of slippy map, talk to OJW first.

I haven't found a way to make the maplint tiles transparent and use
them as an overlay in the OpenLayers thingy; this should be possible
somehow so if someone wants to experiment...

Please note that the selection of checks done by maplint and the way
the results are rendered is just a first shot right now, I believe
there will be good ideas and improvements in the future. Maybe if we
find a good colour-coding of the different kinds of problems then we
can drop textual error messages on the maplint layer altogehter?

Here's the svn comment:

Multi-layer support. Layers controlled by layers.conf (currently
built-in: default layer and maplint layer). Empty layers.conf emulates
old behaviour. All layers rendered off the same downloaded data.

Memory consumption of tilesGen.pl may have increased for complex tiles
as maplint demanded a more fine-tuned approach to merging of multiple

Version name bumped up to "Essen" even though there's no visible
changes on the default layer - I felt the large number of changes
merited that.

TODOs: Make community decisions on what maplint tests should be run
and how they are supposed to be rendered. This version uses a rather
strict set of tests. Tests are encoded in tests.xsl which is generated
by a Makefile from within the original maplint distribution; the
Makefile and the components from which tests.xsl is assembled are not
included in tiles at home.


Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00.09' E008°23.33'

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