[OSM-talk] Tiles at Home client update

J.D. Schmidt jdsmobile at gmail.com
Sun Mar 4 16:45:29 GMT 2007


Jochen Topf skrev:
> On Sun, Mar 04, 2007 at 02:45:02PM +0100, J.D. Schmidt wrote:
>> Jochen Topf skrev:
>>> every client can decide which rendering he wants. 
>> Yes, although a client should not enable NoBezier, unless he has the 
>> following problems :
>> A) Tiles generated with errors like the ones described in Kristians 
>> post, and which has been identified as happening on AMD64 boxes running 
>> Gentoo.
>> B) Persons who for some reason can't get Math::Vec installed, but still 
>> want to participate in the T at H project.
>>
>>> So some clients will
>>> render their pieces of the map differently from others
>> Yes, just like today, where people are running a mixture of clients 
>> version. If you look at the Log page, you can see both Agadir, Athens 
>> and Bangkok revisions running.
> 
> Which is also a problem. Everybody should use the same renderer. Of
> course there is some overlap until everybody has moved to the new
> version. Thats ok, because we are not re-rendering the whole world each
> time we change the code anyway. But old code and old tiles should eventually
> be worked out of the system by itself. Now, for the first time, you have
> created an incompatibility that will potentially last forever. Thats
> what I am objecting to.
> 
>>> leading to
>>> problems at tiles boundaries 
>> Those problems do NOT arise from the Beziercurve hinting used. Think it 
>> over..
> 
> Actually they do.
> 
>> The beziercurve hinting does NOT change the position of the endpoint of 
>> any ways. Therefore the endpoint at the edges of the tile will be at the 
>> exact same point as if they were rendered without the Beziercurve 
>> hinting. I'm putting up an example page on the wiki under the 
>> tiles at home/problems page, which shows two neighbouring tiles rendered 
>> with and without Beziercurvehinting.
> 
> This might be true for a point sitting directly on the boundary. But in
> the general case the point is not directly on the boundary so this
> *will* lead to rendering problems.
> 
>> It REALLY is a Non-Issue.
>> (Or as they say here in Copenhagen at the moment : Move along folks, 
>> nothing to throw stones at.)
>>
>>
>>> and to strange "yesterday it looked
>>> different" problems.
>> That is again not due to the Beziercurve hinting. But due to the fact 
>> there are different client versions running, using different stylesheets.
> 
> See above.
> 
>> The Beziercurve hinting is just that, a subtle hinting that smooth out 
>> sharp bends into curves. On zoom level 12, it's hardly possible to see 
>> it, on higher zoomlevels it gives the roads a more pleasing look. The 
>> only way you can see a difference on the slippymap is when zoomed in to 
>> zoom level 15 and beyond, and happen to look at a boundary where there 
>> are a curve in a road. And then you still need to look closely, to see 
>> the difference, which is only in the esthetics of the render, not in the 
>> actual lineup of the tiles.
> 
> Nobody said that is was in the lineup of the tiles.
> 
> But I see that you see my point which is exactly what you say here.
> There is a difference which affects "the esthetics of the render". And
> thats the whole point. I want the map to look beautiful, I assume you do,
> too. So I don't like this little "difference" and you don't care about
> this difference, because it is too small for you. Well, I do care. And I
> assume other do, too. (If it was that small we didn't need Bezier curves

> in the first place.)
> 
>> You didn't misunderstand me, nor what the option do. You just 
>> misunderstod the ramifications of the Beziercurve hinting. Whether its 
>> because you got some beef with it being implemented this way, or whether 
>> its because you didn't understand how the Beziercurve hinting affects 
>> the data in the tile, I really can't say.
> 
> No need to get personal. Have you considered that I might know a thing
> about how all of this works and my reason for bringing up this topic is
> that I care about nice looking maps?
> 
> Jochen

The proof is in the pudding... See the examples on 
http://wiki.openstreetmap.org/index.php/Tiles%40home/Problems and then 
tell me again it is a major issue ?

J.D. "Dutch" Schmidt




More information about the talk mailing list