A Methodological Framework for Analyzing Digitally Historical Maps Using Data from Different Sources through an Online Interactive Platform

Historical maps are a great resource for many scientists, not only for those dealing with its practice, but also for those of different fields of research, interested in the geographic analysis of the environment. Using historical maps in digital form in conjunction with modern maps or data can offer a variety of benefits to researchers, since it provides to them the opportunity to study the geometric and thematic properties of the maps or to use maps of different time periods to detect and determine changes in the environment, border changes or renaming of toponyms in the area. Nowadays, the development of new Internet technologies gives the opportunity to experts or the general public to gain web access to information and data, to find maps in digital form and download them with or without cost from digital map libraries or private collections. These maps are usually in high resolution but they are just scanned images, needed to be correctly rectified in order to be compared with modern maps. A solution to this problem is the development of a system where the researcher will have online access to correctly rectified maps and will also have the opportunity to compare historical with modern maps inside the platform and use them in his/her research. The aim of this paper is to describe analytically the methodology followed in every step of the procedure from the selection of the historical maps and the collection of modern data to the final use of the comparison tools provided by the platform, giving in that way the framework to everybody to analyze digitally historical maps and to compare them with modern data online inside a platform. In order to make the procedure more clear, we have used examples of historical maps and modern data from different sources, obtained free online through the Internet.