[OSM-talk] OSM map renderer - update

Nick Whitelegg Nick.Whitelegg at solent.ac.uk
Wed Apr 19 11:55:56 BST 2006

>Any particular reason you didn't use exactly the same format as
>Etienne?  (Not that I think you should have, I'm just wondering)

Etienne's is perhaps more geared to SVG (or at least XML) output, through 
the use of XSLT, CSS classes etc.  The format I used seemed the most 
straightforward way to style a dynamically-generated bitmap image. However 
if most people are in favour of one single style format I could alter my 
format to the same as Etienne's, though that would require quite a bit of 
work, as a combined XML/CSS parser is obviously more complex than a 
straight XML parser.

>> Another problem is when two consecutive segments in a street have a 
>> 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 
>> has been dealt with there.

>You want round caps on your lines, I think.

That's what I thought. I looked at the GD documentation and couldn't find 
a way of doing it automatically, whilst a cursory look at the ImageMagick 
docs suggested it was possible.

>> Might also be worth looking at ImageMagick rather
>> than GD as it seems better able to deal with this (not to mention
>> anti-aliasing)

>I thought GD did antialiasing now?  Or is that only on 1px lines?

It does some, just for lines I think, not text. However for whatever 
reason the version of PHP on the dev box doesn't support the 
ImageAntiAlias() function, even though the requirement ("only works with 
the bundled version of GD") is I believe satisfied.

>Possibly worth looking to see if there are PHP bindings for the Anti
>Grain Geometry library - I hear good things about it and the output is
>lovely.  (It also works with SVG so we could keep output consistent
>across all branches of the project).

OK will look at that.


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