1

Hi there

As I am having a bit of an issue with those three terms, I was wondering if anyone could have a go at clearly and concisely explaining what Layers, Tiles and Renderers are?

Cheers!

asked 06 Aug '13, 04:42

stephane-guillou's gravatar image

stephane-gui...
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Thanks Andy! If you put those comments in an answer and expand on the layer part, you might get the best answer tick ;)

(06 Aug '13, 06:07) stephane-gui...

2 Answers:
4

assuming "Layers" means "Layers on the main OSM website" (from your comment, you may add this to your question) and assuming all of that question is about the OSM.org website:

  • layers (if talking about different maps / map styles) are made of …
  • tiles (square bitmap graphics -typically 256×256 pixels- images displayed in a grid arrangement to show a map) are produced by …
  • renderers (software that outputs e.g. a visual map from raw geospatial data -our OSM data- as input)

Layers usually/basically mean something overlayed on something else e.g. the data layer or notes markers over a base map. If there would only be different maps to switch between I would think that "layers" is not a good description but "map style switcher" would be.

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answered 06 Aug '13, 12:19

aseerel4c26's gravatar image

aseerel4c26 ♦
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accept rate: 18%

edited 06 Aug '13, 12:32

1

Layers are used to separate ways on different levels. Is the road over or under the rail line? Do the cross roads have a junction node, so you may turn there, or is it a bridge. This is important for drawing the map and routing, could I turn left or right or only go straight on? Layers are also the backgrounds in the editors such as out of copyright maps, others maps we can use and aerial all of which we can trace from or use to assist us in our edits. http://wiki.openstreetmap.org/wiki/Osmarender/Layers maybe better link http://wiki.openstreetmap.org/wiki/Layer Tiles are squares of map. Each Tile consists of four tiles. Each of those Tiles consists of four Tiles and so on for the 20 or so levels of zoom. each level shows more detail. This is done to speed up the availability of maps on screen. http://wiki.openstreetmap.org/wiki/Tiles Rendering is the drawing of a map from a set of data. These renderings are a bit like artistic styles of painters. They are also made for particular users so a drivers map would concentrate on roads and motorways and show towns and road numbers. A hiker would maybe want footpaths, contours, woods, rivers and maybe campsites. http://wiki.openstreetmap.org/wiki/Renderers

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answered 06 Aug '13, 06:18

andy%20mackey's gravatar image

andy mackey
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accept rate: 4%

edited 06 Aug '13, 15:33

So I guess the word "Layers" on the main OSM website is misused?

(06 Aug '13, 06:22) stephane-gui...
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I count three types of layers:- they are (1) The map layers on the map page. (2) The level layers of rivers, tunnels,roads, bridges and others. used by the renderers to decide which is shown above or below. (3) The choices of background layer we choose from when editing such as GPX traces,out of copyright maps, permitted maps, and allowed aerial sources which are layered under the data of the osm database, but separate from it, which is extremely useful when editing.

(06 Aug '13, 22:53) andy mackey

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question asked: 06 Aug '13, 04:42

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last updated: 06 Aug '13, 22:56

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