OpenGeofiction
Hi there!
Since a week, I try to upload a large group of islands which I created by tracing decomposing, fractalizing and recomposing a bitmap image in Inscape. First, JOSM was collapsing under the sheer number of nodes. I figured out which fractalizing factor to choose and after a lot of nights with useless data imports and hangups, I managed to get the data into JOSM. Now, I’m finally ready to upload. However, I have many polygons with more than 2000 points. It takes a lot of time to split all of them into uploadable chunks, especially when JOSM is quite slow. Does anybody of you know a way which allows to auto-split polygons or lines into chunks with X nodes? Merkaartor would also work, I have both.
Greetings, Markus
Discussion
Comment from zhenkang on 13 June 2018 at 07:27
Just click on a node and press ‘P’. Simple.
Comment from zhenkang on 13 June 2018 at 07:27
:P
Comment from EMKLI on 13 June 2018 at 08:07
I know that I can use P for splitting a path/polygon. However, that’s not what I asked for. As I’ve said, with more than 300.000 nodes on one layer, JOSM gets incredibly cumbersome to use (when selecting nodes etc., it takes the program longer than usual to respond) . It took me more than am hour to truncate 30 or so polygons. So I was looking for a way of automating the splitting process, f.e. selecting a poly/path and apply some kind of auto split function.
Comment from wangi on 13 June 2018 at 10:07
That’s something i’m looking to do too.
Can probably safely say you don’t need that many nodes, have you simplified (Shift-Y) the polylines at all?
Comment from wangi on 13 June 2018 at 10:11
Or osm.wiki/JOSM/Plugins/RemoveRedundantPoints
Comment from wangi on 13 June 2018 at 10:12
Other problem i’ve solved is that loading into JOSM as a GeoJSON file results in lots of duplicate nodes. Wrote a script to fix that in the OSM file.
Comment from Luciano on 13 June 2018 at 15:53
Absolutely you don’t need that many nodes. The very first thing I do with any new line I draw is “simplify” (Shift-Y) (and certainly if I was procedurally drawing fractalized lines I’d do the same). No verisimilitude lost…
For performance issues in JOSM, what I’ve been doing more and more is splitting my work into different layers, and only working on a few individual layers at a time. So, for example, my contour work in JOSM (which is not uploaded and is quite detailed - eventually it will be converted to the background for the TOPO layer tiles), I split my work into at a minimum “degree squares” and even sub-parts of degree squares. I do the same with hydrology (lakes and shorelines) when they’re in draft form (these get periodically uploaded). I have 6 degree squares in Makaska (which overall is only less than 7000 sq km), so I jump between a total of 12 files when working on contours and hydrology. Then I also keep separate layers for place nodes and not-yet-uploaded boundaries, a layer for eventual railroads, a layer for eventual highways, a layer for landcovers, etc. This keeps JOSM from bogging down, and it keeps me organized.