Wednesday, September 30, 2009

Informative Article on DC Streets

The article Washington's systemic streets provided a solid history and explanation regarding DC's street system. Technical but definitely readable.

Tuesday, September 29, 2009

How does the MAR deal with empty lots?

Usually, empty lots will not have an address record associated with it . However, if there is a DCRA approved address for the lot, there should be an address record whose status is 'assigned'. If there was a building, that existed on the lot between 1999 to last year, and that building was demolished then it is highly likely that there will be an address record whose status is 'RETIRE'. The 'RETIRE' status indicates that the building is demolished and / or that the address is no longer in existence.

Empty Lots on the 1600 Block of Kramer Street NE

(Image from Google StreetView)

It is of low importance to the MAR Data Team to add new addresses for buildings that were demolished many years ago. (their status would be 'RETIRE')

Thursday, September 17, 2009

Residential Unit Submission Page

The MAR recently added a unit submission page where residential units can be submitted for inclusion in the Residential Units table. Units can only be submitted for primary addresses which already exist in the address table. To use this feature type go to the MAR Sample Client. Then type in the primary address (without the unit). If the address is valid then one gets to the Location Details page.

On the Location Details page it will show the details of the address. If the address already has residential units (in the MAR) it will show 'Unit: Display / Submit Unit(s).' If the address does not have any units (in the MAR) then it will show 'Unit: None. / Submit Unit(s).' If, for example, there are no units then click on the 'None. Submit Unit(s)' link, the Unit Submission Page will appear. See below image:

The user can then fill out the appropriate information and submit it to the MAR Data Team for inclusion. The submission will be reviewed and a followup email will be sent to the user.

Your assistance is appreciated. Currently, there are 188,298 residential units in the MAR. It is estimated that there should between 194,000 to 202,000 records.

Thursday, September 10, 2009

Searching New Imagery for Change

When DC GIS acquires new imagery there is a a need to perform change detection. Among the things being searched for are:

  • New Buildings
  • New Streets
  • Demolished Buildings
  • Demolished Streets
The new 2009 1 meter Imagery is searched using a a grid which overlays DC. The grid has 350 squares.

While looking at the new imagery, I found two addresses 3203 Georgia Avenue NW and 3205 Georgia Avenue NW which appeared to be demolished (see image at top of blog post). Since the 2009 imagery is of of low resolution compared to DC GIS's 2008 Orthophoto Imagery, I wanted confirmation that these two addresses had been demolished. I check with USPS to see if they were considered deliverable. They were still deliverable (which is and indication that they might be still in existence). So I googled these addresses. I found these two images (3203 & 3205) on flickr which stated these addresses had been demolished. This information coupled with the 2009 Imagery was sufficient to change the status of these addresses to 'RETIRE' in the addresses from the MAR. Demolished addresses receive a 'RETIRE' status in the MAR.

Wednesday, September 9, 2009

What is a Unit Block in DC?

A unit block in Washington, DC is a block that has a theoretical range of address numbers between 1 and 99. Most blocks can be referred to as something similar to the 100 block of Street Name, the 200 block of Street Name, 300 block of Street Name. It is awkward to call something the 0 block of, so instead the block is referred to as the unit block (example: Unit block of T Street NW)

The unit block of T Street NW (from Google Maps). It is located adjacent to, and just to the west of, North Capitol Street.

Unit blocks are located in three types of places:
  • Regular blocks on the address grid, usually located adjacent to East Capitol Street, North Capitol Street, South Capitol Street.
  • Circles (Dupont Circle NW, Logan Circle NW, Sherman Circle NW)
  • Alley Streets (Pomander Walk NW, Walter Houp Court NE)
Also check out Distribution of Addresses 1 - 99 (Unit Block).

Tuesday, September 1, 2009

Monthly MAR Data & Information Report: August 2009

Data Loads into Addresses, Alias, Units, Street Names Aliases:

Dataset Numbers:

  • Addresses: 141,769
  • Residential Units: 187,400
  • Aliases: 5,204
  • Street Name Alias: 1,022
  • Intersections: 16,359
  • Block: 15,826
  • Address / SSL Cross Reference Table: 235,565


We attended and presented twice regarding the MAR at the 2009 URISA/NENA Addressing Conference in Providence, RI. Useful information was learned from the dozens of presentations we attended.

Large development sites (areas) were field visited such as Dakota Crossing, National Baseball Stadium area, Henson Ridge Phase II and the Shops at Park Village. A small number of changes to the MAR were digitized due to the information collected.