Format: 

Cartographer. (Year). Title of map [Map type]. Retrieved from URL

Cartographer. (Year). Title of map [Map type]. Location: Publisher

Examples: 

U.S. Census Bureau, Geography Division (Cartographer). (2005, September 14). Poverty rate by Census tract: Hurricane Katrina disaster areas Louisiana, Mississippi, and Alabama region [Demographic map]. Retrieved from http://www2.census.gov/geo/maps/special/HurKat/Katrina_Poverty_Rate_v2.pdf

In-text: (U.S. Census Bureau, 2005)

Google Maps. (2015). Rochester, NY [Road map]. Retrieved July 29, 2015, from https://goo.gl/maps/JF21A

In-text: (Google Maps, 2015)

Notes: 

Provide only the year of publication unless the information may frequently change (e.g. Google Maps); then, provide the full date of the last revision before the URL.

Source:
APA - 7.07, no. 53