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If I go to openstreetmap.org and zoom into an area I know. I can choose a basemap which appears to be named according to a local authority (in may case LPI NSW Base Map). I can see on this basemap, lots of roads which actually exist. But if I go to my copy of the latest OSM maps, they are not present. It would appear that these roads, which do exist, need to be traced from the base map onto the OSM map. Is that what 'tracing' is all about? I thought tracing was all about ground truthing and providing actual, verifiable trackpoints along a route. But maybe I have the wrong idea. thanks Alan |
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@commenters I suspect @alanmcd is actually using iD and referring to https://github.com/osmlab/editor-layer-index/blob/gh-pages/sources/australia/au/nsw/NSW-LPI-WebServices-BaseMap.geojson @alanmcd OSM is work in progress, if roads or anything else is missing from the map, the whole idea of the project is that you are supposed to add them (from personal survey, legit third party sources and so on). You can find more information on contributing to OSM here https://wiki.openstreetmap.org/wiki/Beginners%27_guide and in many other locations. Well it could be the same thing but doesn't look like this link. When I edit as ID I get a long list of background layers to choose from. One of them is LPI NSW Basemap. It's quite clearly a map of tracks I have been on which are not yet part of the OSM download.
(23 Feb '18, 11:50)
alanmcd
Maybe actually reading the answer would be a good idea.
(23 Feb '18, 12:08)
SimonPoole ♦
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@alanmcd That LPI NSW Basemap is a completely different map to OpenStreetMap. It's avaliable as a background layer in iD and JOSM as we have permission to derive information from that map into OSM. It is useful sometimes to cross-check. Just because it's there doesn't mean you should trace over everything you see into OSM, as it may not be there in reality.
(24 Feb '18, 00:13)
aharvey
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To answer this part of the question: It's actually often about both. If I go somewhere I'll usually save a GPS trace (and I'll actually add waypoints along it with more details). When I get back I'll look at that and I'll also look at the available aerial imagery sources, and add roads, hedges, shops, offices, trees etc. etc. etc. Sometimes it's not possible or practical to go somewhere, so imagery is used alone, and sometimes imagery is incomplete or out of date, in which case GPS traces and other notes are used alone. Generally speaking though, the more sources you can compare the better what gets added to OSM will be. Just to be clear though - someone needs to manually add stuff to OSM though. Just uploading a trace and hoping that someone else will won't tend to work. Yes - that's clear. It's more than comforting, however, that when I submit a trace, knowing that it is quite accurate, that the background confirms it exactly as well.
(24 Feb '18, 00:47)
alanmcd
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by "my copy of the latest OSM maps" you mean what? A download for your Garmin device/Basecamp? (please edit your question text or add a new comment)
Additionally the OSM website does not provide maps named LPI NSW Base Map.
It is definitely there. It's a background layer and it's basically a map as far as I can tell.
Bit of info https://wiki.openstreetmap.org/wiki/Tag:source%3DNSW_LPI_Base_Map