Different scales among maps also make comparison difficult. After 1909 it is difficult to find real estate atlases. According to newspaper accounts Springfield began its change from farmland to suburbia in the 1940's. From 1940 to 1950 its population doubled from 5,480 to 10,795. Unfortunately newspaper accounts are not primary sources, but census data can be located at the Delaware County Historical Society.
Deeds are another primary source which shows land ownership and the changes it undergoes.
At the Board of Assessment in Media, Delaware County, you can look up the address of a property and find out on what book and page the deed is recorded in the county records. In the Recorder of Deeds office you can look up the deed on microfiche and theoretically trace it back to its original owner. This process is very time consuming and can be very frustrating. One of the difficulties dealing with deeds is that of human error. In order to look at a deed you must know the book and page number where it is located.