Hello, I use Maperitive to generate tiles from osm data. Then I use those tiles in my application. The tiles generated are in Mercator projection but my application requires tiles in WGS84. I wonder what options I have: 1. Is there a way to let Maperitive generating tiles in WGS84? 2. If 1 is impossible, is MapProxy the only tool I can use to re-project the tiles from Mercator to WGS84?

Thanks.

asked 26 Sep '13, 07:12

hua%20zhang's gravatar image

hua zhang
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accept rate: 0%

closed 30 Sep '13, 12:33

SomeoneElse's gravatar image

SomeoneElse ♦
32.3k63333753

The question has been closed for the following reason ""Close" was requested by initial questioner; a different question now best reflects what they're asking." by SomeoneElse 30 Sep '13, 12:33


I think you may be confusing Mercator which is a map projection with WGS84 which is coordinate frame for the Earth. All location data stored in the OSM database is stored as latitude/longitude positions using the WGS84 standard. WGS84 is a 3-dimentional model of the earth, to create a 2-dimentional map of a part of the earth this data needs to be transformed and scaled to fit. This is what the map projection does for you. Mercator is just one of many hundreds of different possible map transformations, but is the one used by the standard OSM map tiles.

So to answer your question: Your map tiles are created from WGS84 data using the Mercator projection by the Maperitive application. This is probably what your application requires.

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answered 26 Sep '13, 15:40

srbrook's gravatar image

srbrook
99351225
accept rate: 13%

1

Hello srbrook, thank you very much for explain WGS84 and projections for me. I think I got better idea now. My application is using tiles from other source. I am trying to use OSM tiles instead. After I put OSM tiles in the application, (I tested on a few places,) the x coordinates looks the same as before, but y coordinates are about a couple of kilometres different between two tile source. My first guess was it is probably to do with osm tiles are using a different projection from what the application requires. After I saw this post https://help.openstreetmap.org/questions/23934/osm-and-4326-projection, I am more convinced that this is to do with the different projection.

I will have another look at the application code, and I might need your help again. Thanks.

(27 Sep '13, 04:47) hua zhang

Hello srbrook, my application is using osm tiles as the background layer, and features on other layers are created by mapinfo. Because mapinfo is using NAD83 projection. I guess my question became how to generate tiles in NAD83 projection. To remove confusion, I started a new question https://help.openstreetmap.org/questions/26860/how-to-generate-tiles-in-nad83-projection, and I will close this question. I look forward to your reply in the new question. Thanks.

(30 Sep '13, 12:29) hua zhang

I don't know how to close this question. :(

(30 Sep '13, 12:32) hua zhang

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question asked: 26 Sep '13, 07:12

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last updated: 30 Sep '13, 12:33

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