Import/City of Alexandria, Virginia Addresses

This is a plan for the addition of address point data for the City of Alexandria, Virginia. This effort would build on previous imports that were successfully completed earlier this year for the City of Redlands, California and City of Flagstaff, Arizona, using data preparation procedures developed for those efforts and refined based on OSM community feedback, with different process for mappers to add the features to OSM (see Data Updates section below). For a list of other Esri-curated datasets that are available for mapping, please see Esri ArcGIS Datasets.

Goals

The goal of this effort is to add the City of Alexandria, Virginia Addresses data (where applicable) to expand the coverage of address data for the City, using authoritative data from the City. OSM currently has a more limited set of detailed addresses (including house and unit numbers) in the City. This effort would greatly enhance the coverage of detailed addresses for the City, while retaining the many addresses already added to OSM.

The goal would be to only add separate address points where the addresses are (a) not already included in OSM as nodes (e.g. amenities) and (b) not associated with existing buildings that are available in OSM, unless the address points add more tags (e.g. multiple units within a single apartment building that has a street address). There is more detail on this in the Data Preparation section below.

Schedule

Data preparation was performed in May 2020. The edits to OSM would likely be performed incrementally over the remainder of 2020, starting no sooner than mid-July.

Source

The source address points were downloaded in May 2020 from the ArcGIS Hub Open Data site.

The processed address points are available to access on ArcGIS Online (see City of Alexandria, VA Addresses).

OSM ODbL Compliance: Yes, the City of Alexandria data is provided under a CC0 1.0 Public Domain Dedication.

Data Preparation

The processed address points referenced above were created using these Esri Data Processing Steps for Buildings and Addresses, developed and refined while doing data prep for several city and county communities in the United States. Below are a couple notes specific to the City of Alexandria addresses data.

• The processed data contains a total of 35,567 address points, of which 34,927 addresses were not already represented by points in OSM at the time of final data prep and have therefore been made available through the layer to add to OSM.
• The processed data includes address tags (i.e. housenumber, street, unit, city, state, postcode).

Data Conflation

Existing address features in OSM will not be replaced. The plan is to perform the updates in phases. In the first phase, only new address points that do not conflict with existing address points, or duplicate addresses that are being added to buildings, will be added. If the address is already associated with a building footprint (e.g. house) that is in OSM or available separately to add to OSM, then the address point will not be added separately. However, if the address point will provide additional detail for a building footprint (e.g. apartment building), such as a unit number, then it will be added separately. In future phases, existing OSM buildings that do not have complete addresses may be updated to include additional address tags.

Data Updates

The plan is to perform the initial phase of updates using a updated version of RapiD and an updated Map with AI plugin for JOSM (see Esri blog post on new tools in OSM editors for more detail). The new tools will enable OSM mappers to access ArcGIS Datasets hosted in ArcGIS Online and select individual features to use while editing OSM. The mapper will be able to select a feature, review and edit the feature geometry and available fields, and then save their edits. The new tools will use a conflation service (or similar logic) to help identify features in the ArcGIS Datasets that conflict with existing features in OSM and not display these features so they are not inadvertently duplicated in OSM.

The mapper will have the benefit of using existing features that have been created by the data provider, along with their available field values that have been pre-processed by Esri, while also being able to compare that feature with existing OSM data (e.g. street names, house numbers) and imagery (e.g. Bing, Esri, Mapillary, etc.) to ensure it is accurate and consistent. The data source used for the edit will be added as a tag to each feature that is saved as part of a changeset.

Accounts

The plan is for most OSM mappers to use their standard OSM accounts if they are editing with RapiD and JOSM editors for OSM and editing individual features. However, if Esri staff do any 'bulk' edits for a large portion of data where we do not review individual features, then we will create and use new dedicated import accounts (e.g. <username>_alexandria_import) for those changesets. We encourage other OSM mappers to do the same.