Hello,
I am doing some digitising of a map. To be able to use the polygons in a numerical modelling tool, I need the polygon edges (where they meet) to be exactly the same, and have no gaps etc.

In many cases I don't *have to* create polygons for every feature - i.e. I can simply connect lines together and the modelling software will work it out, but in some cases I need to duplicate a shared edge. I have been able to duplicate the existing polygon, then split it into segments and delete the excess segments, but it would be very nice to be able to have some sort of autofollow feature where I can set a new polygon edge to exactly match an existing one.

Wishful thinking?

Ben.

Hhhm, I don't know of such a feature, or about the feasibility of such a new feature. But if you're not already familiar with Inkscape's snapping and grid features, especially snapping to a grid, you might find that helpful. That is if your polygons could conform to either a rectangular/square or axonomic/isometric grid.

No, these aren't regular shapes unfortunately. The image in the post at viewtopic.php?f=5&t=10382&p=38602#p38602 gives an idea of the sort of shapes.

You could draw the lines once, then - when all is drawn - combine them into a single large path and use that to 'Path >Divide' a rectangle as large as the digitized map: this will create individual shapes which share the same edges.

(to optimized the result of 'Path > Divide', you might need to extend the segments near the edges of the rectangle to be divided so that they extend beyond the edges of the rectangle -> in the node tool, drag those nodes with 'Ctrl+Alt' pressed (which will constrain the movement aling the direction of the line segment or the node handles if curved)).

Ah, now that is power user stuff. Fantastic advice, thanks again. That'll make it much quicker than trying to make polygons everywhere.