New Release: MAR 2 API Version 2.1
Hello District Developers and Data Users,
In our March newsletter, we announced enhancements made to the MAR 2 API, as well as updates to the Data Developers Portal.
This quarter, we’ve released MAR 2 API version 2.1. Here’s what you need to know:
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Block Key and Sub-Block Key: For decades the District’s MAR has used DDOT’s street segment identification system for roadway centerlines. Now, DDOT has retired street segment IDs and moved to using an updated system of block key and sub-block key. With this major data schema change, two new values will replace several existing fields used to locate addresses, blocks, and intersections. DDOT has prepared this Wiki site to explain the history of street segments and the new block and sub-block keys. With this change, the following fields will be available through the end of 2022, however, beginning January 1, 2023, they will not be populated and will contain null/empty values in previous versions of the API.
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Blocks: Previously, the API provided the actual address ranges for block center-points along a roadway for a matching block, in addition to the addresses along that block. Going forward, “0” will be the value for the “actual range” fields. Theoretical address ranges will continue to be provided. Refer to the MAR 2.0 data dictionary to see a description of these fields. Also, blocks are now related to addresses by their block key as opposed to their “streetsegid” value. All addresses associated with a block key will be returned.
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Additional Zones: Zones help us determine the different geographic boundaries in which a location falls within. Version 2.1 of the MAR 2 API now offers zonal outputs for Advisory Neighborhood Commissions (2013), Single Member Districts (2002 and 2013), Wards (2002, 2012 and 2022), Neighborhood Clusters and Voting Precincts. This point-to-zone feature allows users to aggregate data for displaying in charts, understand the distribution of data across DC, or simply to validate a location within a boundary. Have you ever found a point to fall on the borderline of a zone? The MAR 2 API handles this by providing results as an array of multiple zones. View the full list of available zones.
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Residential Units: We’ve improved how residential units are categorized. Values were previously returned as either “condo” or “rental,” however, this did not consider that a “condo” may be a rental unit. Now, the values are returned as either “condo” or “non-condo.” Learn how to perform unit searches.
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Address Status: With this update, a larger number of addresses are now provided due to the inclusion of retired addresses. Most of the newer “retired” locations have been assigned a negative MARID value. By only returning MARID values greater than 0, the result set should remain relatively consistent to include the “retired” features that were previously being returned. A future release will modify this so only “active” addresses, blocks, and intersections will be returned by default and a new parameter will be provided to allow for querying additional statuses such as “retired”, “temporary” and “assigned.” See the MAR 2.0 data dictionary for more definitions.
Learn More
The MAR 2 API for application developers is publicly available to individuals and organizations needing to verify addresses, place names, blocks, and intersections, and develop applications and build systems using Washington, D.C. addressing data across all platforms. It is developed with a modern code framework that provides output in modern data exchange formats. Using newer technology such as .NET Core and ElasticSearch, MAR 2 API’s dynamic responses allow for the return of objects and results with or without associated zones (geographic boundaries). The Data Developers Portal for MAR 2 API is the developer guide to building new applications that need authoritative District government addressing components and obtaining location data that will enhance your location-based analysis within the District of Columbia.
Contact us at data.dev@dc.gov with questions or feedback.
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