when i 'm importing image and terrian from google earth the image comes without original colors , and i don't know the scale of the image
thanks
1) You can't import color images from Google Earth:
2) Images are scaled according to your view scale and are scaled as noted in these posts;
http://forums.autodesk.com/t5/AutoCAD-Civil-3D/Google-Earth-Image-import-shift/m-p/2815180#M140013
http://forums.autodesk.com/t5/AutoCAD-Civil-3D/Google-Earth-image-problem/td-p/2543108
As noted in the above posts, due to the way C3D scales the images the dimensional accuracy can be very crude so check the accuracy before using them for any type of layout or analysis.