A common GIS development task is the need to digitize data off of a paper map. There are two main ways to do this:
Digitize using a digitizing tablet.
On-screen digitizing from a background (scanned) image of the map.
This document describes part of the process for on-screen (#2) digitizing: Getting a background image georeferenced so that you can do online digitizing using it, or simply use it as another GIS (raster) layer.
First, you must identify the map you want to digitize and check it for metadata.
Check for georeferencing coordinates (are there long/lat lines on the map? UTM coordinates? What kind of datum/map projection is it in?) (See Appendix A for an example from a USGS topomap).
You must also check for some usable Ground Control Points. These are points on the coordinate grid that you can easily see and calculate X,Y coordinates based on the projection the map is in. (See Appendix A)