With a paper map all the information is contained within a single sheet of paper. This information may tell you all you need to know about some basic features of the map. However, if you want to carry out more specific tasks involving spatial queries and analysis the paper map has many limitations.

Firstly, to avoid the original map from being marked the answer is to use some form of overlay such as a plastic sheet. With this technique you are able to put points, lines and polygons on the map without effecting the original. Whilst this is one way of using a map to analyse data it is far from satisfactory. This is where a GIS system is far more effective. With a GIS you can have a base map similar to a paper map and then add as many layers as needed to this to create the analysis you require.If you were a local authority you may want to have layers for lamp posts which would be represented by a points layer, land boundaries which would be represented by polygons or roads which would be represented by line layers. The same base map would be used by different departmental users for completely different applications without the problems normally associated with paper maps.