Hi everyone !

I'm trying to come up with an accurate map of an airsoft play field, since the google map basically shows a big bunch of trees.

I plan to proceed as follows :

1. Trace a polygon over the field boundaries on google earth
2. Go there with a GPS and take coordinates of key points in the field, such as top of hill 1, start of path 2, etc
3. Pin those points back on the google earth map
4. Modify the picture with GIMP, to end up with only a white background with boundaries of the zone and dots for the key points
5. Upload this file on CD3 and draw on it

Problem is, I have no idea how to upload a background file in CD3. I tried the Draw > Import file, but it then makes me drag & drop it, making it impossible to have it on scale.

Could someone please give me a hint on this ?

Thank you