It is important to figure out cartographic information for images you plan to add spatial reference to. Read the data description section of the map to define projection, datum and units for the map. In this excersise we get the following from the data description section:

At the next step we need to identify several points on the image for which it is possible to define coordinates. It is easier to select points located on "cross-hair" of the map.

Figure 1: Defining coordinates of a control point

We use the scanned topo map to find out coordinates for four points. A detailed image is also available. The Table below summarizes X(East)/Y(North) coordinates for four control points:

We will use this information to georefference the topo image.