Reply to self... I saw reference to 5m contours in the default rendering file, but in the UK I don't see them on the map with the "high" setting, no matter how far I zoom in. I was already wondering how they would make sense if the accuracy is +/- 5m. The improvement in quarries I thought I saw was either placebo or improved 10m contours.
If anyone knows about OsmAnd's current status and plans, I'd love to hear from someone who knows what they're talking about! On Friday, July 10, 2020 at 2:21:06 AM UTC+1 A Thompson wrote: > Hi! I'm no expert, but have experimented with this sort of thing. As far > as I know: > > OsmAnd's elevation data comes from the NASA SRTM/ASTER data that is > available freely for the whole world except towards the poles. This has a > horizontal resolution of 1 arc-second, about 30 metres. The vertical > accuracy varies but seems to be no better than +/-5m. So it doesn't make > sense to have contour line spacing too close. > > OsmAnd's contour lines are pre-computed in the download, rather than being > generated dynamically on your device from raw elevation data, so you can't > try closer spacing just by tweaking the rendering styles. > > Many countries are providing open access to more accurate DTM/DEM data > from LIDAR surveys. In the UK we have this only for flood modelling, which > if one's interested in hills is the opposite of what one wants! LIDAR data > can be amazingly accurate, e.g. you can see the shape of a car. If you have > such data, you can generate your own contour lines in QGIS and get them to > show in OsmAnd. If you're interested I could post some notes I made when I > tried it, but it requires a little dedication. I found that I could now see > features such as cliffs and quarries that had not been marked as such on > OSM, but for me it wasn't worth the large file sizes of what I had > generated. That was three years ago when OsmAnd's minimum spacing was 10m - > I hadn't noticed that the "high" setting now gives 5m. This shows my > missing quarries, but must be the limit for SRTM data. (Unless OsmAnd is > now tapping in to LIDAR? I can't find any information on that.) > > Just google any of the terms I used if you're not familiar! I hope that's > of interest. > > On Thursday, July 9, 2020 at 7:53:18 PM UTC+1 mika.va...@gmail.com wrote: > >> So i live in the Netherlands, and the landscape is pretty flat here. >> However we still have some small relief in the landscape. Most of these >> little hills are no more then 20m but they can be pretty steep. Therefore i >> would like to have contour lines to better estimate the terrain. However, >> the standard contour lines in Osmand only come in three set intervals, Low, >> medium and high. I beleive the high setting displays the contour lines at >> 5m, but this is still not enough. Is there a way to get these contour lines >> to display at a custom interval, like 1m? is this maybe possible by editing >> the rendering file? i would love to hear back from you guys! > > -- You received this message because you are subscribed to the Google Groups "OsmAnd" group. To unsubscribe from this group and stop receiving emails from it, send an email to osmand+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/osmand/6952e59d-cf22-42c4-855d-8e486204e9a9n%40googlegroups.com.
