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#1 2021-02-17 08:56:56

dgoldman
Member
Registered: 2021-02-17
Posts: 3

OSM Tiled Web Map - Problem with Coke County, Texas?

Using leaflet javascript library, I use the following command:

new L.TileLayer ('http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png');

Everything works fine, with one exception. Coke County, Texas has a green background, such as that it is heavily forested. It is not.

Here is a picture showing problem: https://www.ehdp.com/out/green-coke-county.gif

I did not color it in. It seems to come that way. Can someone please fill me in on what is happening, why the county is green?

Is there possibly another variation on http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png that I should use? Any advice appreciated.

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#2 2021-02-17 11:21:49

SK53
Member
Registered: 2009-01-11
Posts: 627

Re: OSM Tiled Web Map - Problem with Coke County, Texas?

Nope it's totally fine (working as expected). Just that someone decided to map various natural features within the boundaries of Coke County at quite a detailed level: much seems to be natural=scrub & natural=grassland which are both rendered with a green colour. The actual mapping seems rather arbitrary.

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#3 2021-02-17 19:34:47

dgoldman
Member
Registered: 2021-02-17
Posts: 3

Re: OSM Tiled Web Map - Problem with Coke County, Texas?

Thanks. Yes, the tiled maps work as expected. However, I wouldn't say it's "totally fine" for one county to have the natural features mapped at a detailed level, and none of the other counties have any natural features. If nothing else, it's inconsistent. It's especially a problem for me, because I make choropleth maps (each county colored according to the rate of some indicator). If only one county basically comes with a green background, I think everyone would agree that is a problem for choropleth mapping. Actually, any mostly colored background interferes with coloring a map, so if all the counties showed the natural features that would also not work well. I think it is pretty common for people to make choropleth maps, so I am probably not alone here, although apparently the maps are perfectly OK for most other users. Any suggestions appreciated. Specifically, is there a way I can get tiled maps totally lacking natural features (lacking broad background colors)? That would be ideal for making choropleth maps.

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#4 2021-02-18 14:01:58

SK53
Member
Registered: 2009-01-11
Posts: 627

Re: OSM Tiled Web Map - Problem with Coke County, Texas?

It's fine because this is how OSM works: there is absolutely no guarantee that features will be mapped at the same level of detail across the globe. So there will always be areas with more detail than others, this just happens to be an extreme example, but there are others (a patch of Amazonian rain forest with lots of waterways mapped, landuse in Georgia, etc. etc). In general the solution is: a) establish if the data in OSM meets your needs; and b) choose an appropriate OSM based map for those needs.

In your case, the main OSM Carto-CSS style is very unlikely to be a good choice of background for thematic maps, at least at a state level: it contains huge amounts of detail which can obscure features most useful for orientation in a thematic map. There are some other choices, take a look at the various backgrounds offered on umap.openstreetmap.fr. There is also a monochrome version of the main map which may reduce the issue.

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#5 2021-02-18 20:29:51

dgoldman
Member
Registered: 2021-02-17
Posts: 3

Re: OSM Tiled Web Map - Problem with Coke County, Texas?

Thank you very much. You've been very helpful. I consider my question answered.

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