Hi,

I have a requirement to display a default map for a country at zoom level 10. i.e. I need a vector map for a country at zoom level 10 so that the user can use it as default map. The map has to be generated using Osmosis's --mapfile-writer plugin and to be used by Mapsforge APIs on the Android device.

Note: I use polygon files to extract country info from Planet OSM.

Thank you for your suggestions.

  • ananth

asked 08 May '12, 03:44

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kris
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edited 08 May '12, 17:42

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stephan75
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1

Was there a question in there?

(08 May '12, 10:09) Gnonthgol ♦

Are you asking someone to do something for you, or asking how to do something? It really isn't clear from the question which.

Perhaps if you can add a bit more detail saying what you've tried and what didn't work, or perhaps that someone's asked you to do something and you're looking for "getting started" tips?

(08 May '12, 10:54) SomeoneElse ♦
1

The question is: How do I generate a vector map file (.map file) using Osmosis plugin for a particular zoom level?

For example, if you convert a osm.bz2 file (for a smaller area) to vector map file, there is no option to generate the map file for a particular zoom level. By default the vector map generated by Osmosis (--mapfile-writer plugin) generates for all the zoom level (making it heavier??)

Thanks

Kris

(11 May '12, 07:31) kris
1

Do you know the difference between a bitmap tile based map and a vector based map?

When you use tiles, then you have to define what zoom levels are to be created by a renderer.

But with a vector map there is no need to define zoom levels if you create the base map file. Because the renderer is painting the map on-the-fly ... ok?

(11 May '12, 18:15) stephan75

Hi Stephan,

Thank you for your reply.

I do understand the difference between bitmap tiles and mapsfile-writer generated vector map tiles. Some of the areas are pretty big to use as vector maps. Say for example, Europe. The mapfile-writer plugin generates the vector map file having all zoom levels.

What Im trying to do is that if a vector map can be generated having zoom levels from 10 to 18, it may be sufficient (such that the map file size is lesser than having a map with all the zoom levels).

  • ananth
(13 May '12, 17:36) kris

A bit more confusion. Of course we are doing (scale/zoom) level generation and tiling on vector/parametric map data. Especially when we pretend on efficient server – client vector data transmission by streaming via cellular networks. Scale levels and tiling are essential for any modern (vector, raster or mixed) mapping system. But generating pre-scaled vector versions (polyline smoothing, data reduction …) and tiling (multi-tiling where the last/client tiles are generated on-the-fly) are complex and complicated subjects. As a rule the corresponding algorithms are IPR or license protected (or kept as technology secrecy). Tuning of parameters requires extensive experimental work and there are no unique formal rules for these algorithms. Therefore, don’t be disappointed if you don’t find (good) answers to your question in the public domain. “Free” versions of such tools are, as a rule, just a kind of invitation to go for the commercial versions.

Finally, all the above stuff has nothing (or very little) to do with OSM. Slippy map, Mapnik, Osmosis, Opentiles, Geofabrik, Mapsforge … are only examples how OSM data may be used. But in this area tings are rapidly changing.

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answered 14 May '12, 09:52

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sanser
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question asked: 08 May '12, 03:44

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last updated: 14 May '12, 09:52

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