I make maps for wikipedia. I redraw png-maps and create svg-maps. Like this one:
http://commons.wikimedia.org/wiki/File:Byzantine_Empire.PNG

What I have tried is to import the png-file and to open a (blank) map (svg-file). How I can trace png-file onto the svg-file in more or less the same way as ppl used carbon paper to copy files.

What I am not looking for is to use the function Trace Bitmap. I know what that can do.

I want to copy/draw the borders of the empire as portrayed in the above png-file as precisely as possible in the svg-map.

Has anyone a clue how to do that? Thank you beforehand.

Absolutely can be done!

You only need one file. Open a new blank Inkscape doc and import the PNG. Create a new layer (by default, it's created above the original, which is just what you want). Usually I will reduce the opacity of the layer containing the PNG, which requires the Layers dialog (from Layers menu or button on the command bar). But it's not necessary. It just depends on your preference, and how much contrast you need to see what you're doing. Then simply draw on the new layer and trace the outline that you need.

I always just follow the outline with the Pen tool, placing nodes at strategic places. This results in a path consisting of straight segments. Then afterwards, I use the Node tool to change certain nodes to smooth, where a curve is required, and adjust the handles to match the original. Depending how much detail you need, you might want to zoom in. I've found that the more I zoom in, and the more nodes I create, the more accurrate is the result.

Rather than click with the Pen tool, which creates corner or cusp nodes, some people do a click + drag, which automatically creates a smooth node. But I find it hard to control the curve with the Pen tool. And if I have to go back with the Node tool to fix it anyway, I might as well just click to create cusp nodes.

One thing always trips me up though. I often forget to make sure I'm drawing on the new layer. Well, it's not a major problem, because you just have to move the new path(s) back to the proper layer. But it can be annoying, lol. Really it's just a matter of paying attention, for me

Let us know how it goes

Last time I did something like this, I used potrace. Since I'm using Ubuntu, I can download it with the Ubuntu Software Center but you may have to get it from Sourceforge. Your source must be a bitmap (PBM, PGM, PPM, or BMP format). To get one, import your PNG to GIMP, enhance the area you want as your object, erase everything else and then save as a bitmap.

Also see:

• Tools - Inkscape Wiki
• Potrace at Sourceforge

Trace Bitmap is basically potrace!

i remember seeing another trace program that wasn't potrace...which produced good results from photographs, when enough detail level is selected. that's something that potrace can't do very well (yet?). but that's an entirely aside subject.
when i traced diagrams or maps, had the png on the lower layer locked. that way you don't accidentally select and move the png or draw on that layer.
probably some of the techniques used to produce avatars would be suitable? i don't have a knack for those things yet...and things like maps (to me) have similar qualities. when i try to trace a map or a photo, often the outline has the wrong feel, and totally unlike the original bitmap.

I wanted to trace the map not the trace bitmap-way because the old map is of bad quality. I don't want to convert the old map into svg. I wanted to make a new map with the borders as accurately drawn onto it.

This is how I have done it: I used Trace Bitmap on the old map and opened it in Inkscape. Changed the opacity somewhat and opened the new map. Tracing is not entirely possible but it turned out pretty well.
I will try it the way brynn does next time.
This is the result:
http://commons.wikimedia.org/wiki/File:RomanEmpire_117_e.svg

Thank you for answering.

Tried the way brynn works and it works fine. It is necessary to work with layers.

There's an alternative tracing tool other than potrace (built-in into Inkscape) that was able to trace just lines etc. I forgot its name though. Send me a reminder via PM and I might dig it out for you.

I think the other trace engine you're all trying to remember is this: http://www.roitsystems.com/cgi-bin/autotrace/tracer.pl I didn't mention it because Amadeus12 said he/she didn't want to automatically trace it. But actually it has a centerline trace option, which might suit their needs. I'm not sure, and you'll just have to experiment with it, and see what happens.

Yup, should be it http://autotrace.sourceforge.net/