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opensciencemap / vtm

a vector-tile map library written in java - running on android, desktop and within the browser
GNU Lesser General Public License v3.0
238 stars 176 forks source link

map movement influenced by tile rendering and loading #88

Open apachemaven opened 10 years ago

apachemaven commented 10 years ago

Hi:

I found that map can be hardly dragged once dealing with too many features to be rendering, so does the tile loading.

IMO, the tile loading and rendering should be put at a separate thread from the UI interaction, but it seems that this is how vtm do it. But I am not sure why the performance went down for lots of data.

We have simplified our data before send them to the client, but we still found the map move,drag,zoom may be un-responsible for some zoom levels.

Any solution to improve this?

hjanetzek commented 10 years ago

There is not much you can do but reduce the amount of data in the affected tiles and zoom-levels

apachemaven commented 10 years ago

In fact, I am interested in the behind technology. Since when I use google map or other vector map product, I found the movement is rather smooth, while the amount of the data is not little at all.

hjanetzek commented 10 years ago

If you look closely you'll find that gmaps on mobile is using bitmap tiles up to z13 and using comparatively few vector features. You can use various gl tracer tools to analyze what is drawn by gl - this also works for gmaps btw.

Sure there are some things that could be optimized in our rendering, like using indexed triangle meshes for polygons, depth sorting do avoid overdraw, ...