[OSM-talk] OSM map renderer - update

nick at hogweed.org nick at hogweed.org
Wed Apr 19 08:39:28 BST 2006

One or two updates on the OSM map renderer:

- Now attempts to draw street names at zoom levels 13 and greater (12 is the 
default). Note that street names will only be drawn if the segment is long 
enough to contain the street name. Note also that if a way is named and the 
constituent segments are not, no name is displayed (this is because I have 
removed the SQL which deals with ways as it was too slow, though I believe 
Steve has some faster way SQL which will be imported subsequently)

- Look and feel determined by a rules file, similar in concept to Etienne's 
approach. The idea is that users will be able to create and upload their own 
personalised rule files to display maps the way they want. The current 
default rules file can be found at


I'll put something on the dev list explaining this in more detail.

- A number of the new-style tags (e.g. highway, waterway) incorporated in the 
rules file. This now means the Weybridge area shows up particularly well, 
with the railway and river clearly marked out.

- Roads are drawn in logical order, i.e. footpaths first and motorways last.

The map generally looks OK at 1:50000 type scales. However there are still a 
number of issues at more detailed, street-level scales, relating to the old 
"segment spanning multiple tiles" problem. I'll take a look back over the 
posts on this last week.

Another problem is when two consecutive segments in a street have a tight 
angle (say 120 degrees or less) to each other. At detailed scales, the 
segments look non-contiguous. I'll look at the applet code to see how this 
has been dealt with there. Might also be worth looking at ImageMagick rather 
than GD as it seems better able to deal with this (not to mention 


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