The MAR Geocoder is a desktop application, built by OCTO, that employs the District of Columbia’s ​MAR Web Service​. The web service has several built in quality control tools that review records presented and take advantage of several look-up tables for alternative names, abbreviations, misspellings, etc. This ensures that the resulting data adhere to the District’s addressing standard.

The MAR Geocoder is designed to geocode a large number of records stored in an existing Microsoft Access table (2003 or newer); or an Excel spreadsheet (2003 or newer). The MAR Geocoder is designed to accept location records containing a single address, intersection, block, or a place name. The MAR Geocoder matches address information to physical locations (latitude/longitude) locations in the District of Columbia’s MAR database, via an internet connection. Since the MAR database includes only addresses, blocks, intersections, and place names located within the District of Columbia (Washington, DC), the geocoder tool will not geocode to locations outside of the District.

Read more in document.