We therefore will calibrate according to these four points. This will permit us to reproduce the calibration at a later time if the map has to be removed from the table. Choose the projectile system by typing p at the command prompt. To return to the digitizing screen, type zoom extent at the following command prompt. The next step is to create some layers.
Layers are like transparencies on an overhead projector.
One layer is always the 'current layer'. Put data you want in separate coverages on separate layers. Make the 'branches' layer the current layer and get back to the 'Command' prompt. The first question you have to answer is from what point the line should be drawn. Enter this point by clicking on the point on the digitizing tablet.