If nothing is available, maps must be produced from scratch.
This means that all elements displayed on the map will be extracted from the aerial photos using stereo compilation.
A few years ago, when computers were not available, or not powerful enough, the stereo compilation system had a direct output to films used to print the maps. One film was used for each colour used for the map (blue for rivers, brown for contours, etc.). These films where then edited manually to apply patterns, place text, etc. before to be sent for printing. The previous editions of the topographic maps of Namibia (before independence) were produced like this.
Nowadays, even if the analysis is done on analogue (i.e. non-digital) pictures, the result is a computer file of set of points (or lines) each having 3-D coordinates (X, Y, Z). These points and lines are then used in a graphical editing software to apply colours, line width, patterns, etc. The data produced by the compilation process are processed and analysed with Geographic Information System (GIS) software. GIS can be used for the map production, but it can also serve many other purposes, such as analysis combining multiple sources of data, etc.