[OSM-talk] JOSM geometry support

Christoph Eckert ce at christeck.de
Thu Aug 23 22:10:33 BST 2007


> I'm a bit unsure at the moment how one would best implement
> these functions without interfering too much with traditional JOSM
> functions - maybe create an extra layer or so... what geometry
> functions do *you* want and how would you like them?

you shouldn't have asked ;-) . I'm working in the CAD world, so if 
things sound fuzzy, don't hesitate to ask me for clarification:

* Assumed segments would disappear, the segment tool would disappear as 
well. Then we'd probably (and hopefully :) have a node and a "way" 
creation tool

* As a way without tags IMO isn't a way at all, I'd just call it a 
polygon or polyline

* CAD applications usually provide a set of (configurable) snapping 
modes. One of them usually is a grid (and I doubt it is of any interest 
for our purposes). But further snapping modes exist so you can snap 
directly to objects (nodes, polyline edges, center of objects, virtual 
crossings of objects etc.). A third one I can imagine are modifier keys 
which allow to align a polyline segment in fixed angles to the 
previously drawn segment or to adjacent objects (e.g. 30°, 45°, 90° 
etc.). This would not allow yet to draw a house front in parallel to a 
street, but at least you can draw perpendicular lines

* That's not enough yet to create a perfect rectangle: It will be 
difficult to draw the third segment/fourth node of the rectangle. Thus 
imagine the snapping mode: It would allow to place the fourth node at 
the virtual crossing of a perdendicular to the first and the second 
segment through nodes one and three. After placing the forth
 node, the polyline can get completed to a perfect rectangle simply by 
clicking on the very first node created

* BTW: If such a polygon/polyline tool made sense, it would be cool if a 
click on an existing segment would automatically "insert node into 
segment" to form a junction with one and the same tool (somehow a 
combination/shortcut of the existing "insert node into segment", 
"create segment" and "create way" tools). Even better, snapping could 
also enable that the last drawn segment/the autoinserted node gets 
inserted right at the point where the adjacent segment was 
perpendicular to the segment which is about to be split

* Combined with the snapping modes, a rotation tool could be useful. 
Select a set of nodes/polygons, click at the rotation's center point, 
click at a second relation point and then the third point to define the 

* Similar to the existing aligning tools (circle and line) I can imagine 
a "perpendicular" aligning tool which adjusts three selected nodes

* The move tool could learn to move polylines as a whole. When clicking 
on an edge of a polyline with the move tool, it could try to move the 
entire object (including it's nodes) except of nodes that form 
junctions with other objects. This would it make easier to move areas 
around, especially buildings come to my mind. Though we'd still don't 
have many of them, we will see more and more as soon as we have all 
streets mapped (which surely will happen soon :)

* A further tool I sometimes miss is a tool that can connect two 
crossing ways by inserting a node into one way, splitting the other and 
connecting it to this node as well. If you imagine one street already 
exists and you want to create a second one that crosses the first one, 
it would help a lot

All that said, I should finally shut up as I cannot write such code by 
myself. Thus my pain receptors are prepared to read the "give the code" 
comments :) .

Just my two cents,


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