Linguistic Atlas Project

http://polyglot.lss.wisc.edu/dare/dare.html

It presents a group of research projects performed for the last 80 years around different parts of the United States. Such as the LAMSAS that collected 1162 records, from 1933-1974 in the Middle and South Atlantic States; the LAPNW that researched the Pacific North West from 1953 to 1963.; or the AFAM that collected data focusing in African-American and Gullah speakers. Some of the interviews are taped, others were transcribed.
The map allows us to visualize the coverage of each project.
Just a fraction of the data has been digitalized, though their goal is to make all of it available. For the ones that can be browsed it is possible to search for specific linguistic features, for instance the occurrence of " ain't I?" in the Gullah dialect; or the map of the pronunciation of the vowel in "just" in the Pacific North West. When completed it will be an interesting source for diachronic analysis.