I have tried to trace this image of a roadsign



getting this result



As you can see, the right edge is gone, and the corners that are supposed to be rounded like in the original image are not properly rounded, they are rather described as jagged. Could the settings for the tracing be changed in order to get a better result?

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Yes, I see what you mean. However, these seem to be rather minor differences. If you will read in Help menu > Inkscape Manual (tavmjong bah Guide) > 19. Tracing Bitmaps, you will note that this feature is not meant to accurately reproduce all images. Many simple images such as yours can be traced fairly faithfully.

I'm not sure if different settings might help or not. Personally I haven't had much luck using Trace Bitmap, and don't understand much about it. But I'm sure others can help with this (if it can be done). Please tell us what settings you used.

Sometimes you can obtain a better result by using another application like VectorMagic