On Tue, Sep 14, 2010 at 10:02 PM, Gavin Scott <[email protected]> wrote: > Using JOSM or Potlach can I control at what zoom level roads I draw, become > visible?
Sort of. In JOSM you can select and hide things that would otherwise make your editing difficult. I don't recommend hiding objects while editing as a newbie though. There is a risk that you will hide something that is important to consider during your edits, and inadvertently break things. For example, you might hide untagged ways and cause a building relation to disappear, then add a new road or alley that overlaps the building. In reality you should have moved the building, alley or both to avoid unintentional overlap. This is a trivial example. Other potential breakage could be pretty significant. But I think what you are asking is this, "Can I edit something in JOSM or Potlatch so that I control at what zoom levels it appears on the OSM web site tiles?" And the short answer there is, "No, you can't". Here is why, and I apologize for the length of this answer. The visibility or objects at different zoom levels is determined by the cartographers who create the maps we view. They decide if pubs are displayed at all (usually yes) and at which zoom levels bike shops appear (on OpenCycleMap). The cartographers make those decisions. Now some background, and other ways to get what you want. We, as mappers, strive to represent object in the database accurately. Cartographers turn that in to a map that suits their purpose either as a general-purpose or specialty map. Sometimes, that means that some things don't look the way that we might have expected on every different map. When things don't look as we expect there is a temptation to change the object in the database to something else, just so that it will look better in one map or another. That temptation should be resisted. We call that "tagging for the renderer"[1] and it is to be avoided. So what can you do to make maps look the way that you want them to look? Some services will allow you to enable and disable different layers.[2] This may provide you with the flexibility you seek. If you have bigger plans for a specialty map then perhaps you should become your own cartographer by learning one or more of the rendering tools, and creating a map of your own rendering rules. This gives you the greatest control over what is displayed when, and exactly how things should look. I should also note that what you see, and wish to change, might be some sort of rendering bug, or mistake somewhere in the editing or rendering of the map. If you see things that strike you as mistakes, you can share them with other mappers on the various lists, to see if other mappers agree with your interpretation, or if they can suggest another correct method of tagging. If you disagree with the judgement of the cartographers, and believe that curling rinks should be shown on a specific map, you can request an enhancement from the cartographers of that map. If you see what appears to be an error in the rendering tools, like an icon that is half-missing, that might be suitable to report as a bug in the rendering tools. [1] http://wiki.openstreetmap.org/wiki/Tagging_for_the_renderer [2] http://toolserver.org/~osm/styles/?zoom=17&lat=43.64953&lon=-79.38181&layers=B000T0FF0000F0FFFF _______________________________________________ newbies mailing list [email protected] http://lists.openstreetmap.org/listinfo/newbies
