Outsmart Sub-Addressing: Tips For Getting Your Sub-Addresses In Order

Sub-addressing is a highly useful and largely unregulated practice. These datasets are beneficial for a number of industries, including mail delivery, utilities, and public safety emergency response. As localities further their journeys to Next Generation 9-1-1 (NG9-1-1), many are interested in adopting best practices associated with sub-address data collection, assignment methodologies, details to include, and maintenance. Because sub-addresses are not required for a successful transition to NG9-1-1, there is no NENA standard to specify what localities can and cannot do with this data. As such, DATAMARK’s public safety GIS experts have published this blog to help local GIS managers and public safety personnel demystify the sub-addressing process and provide best practices to support future workflows.

When To Sub-Address

GIS stakeholders should assign sub-addresses for campuses, multi-tenant buildings, and large buildings with multiple entrances.

Trailer Parks, Apartments & Homes With Granny Flats

Creating logical sub-addresses for these dwellings can help everyone find locations more easily.

Large Campuses Using A Single Address

For public safety personnel, arriving at the closest entrance to an emergency on a large campus can shave seconds off response times.

Public Areas Like Golf Courses And Parks

Use labels to designate locations of prominent features, like baseball fields, water features and utility buildings.

Data Curation

Most of the time, GIS and/or public safety departments don’t have to start from scratch when gathering sub-address data. There are likely several agencies in your jurisdiction that are already maintaining these datasets for specific use cases.

Top Considerations For Sub-Addressing

1. Build the foundation: Ensure that road centerlines, main address data and PSAP boundaries are up-to-date and in alignment with NENA standards prior to adopting a strategy for sub-addressing.
2. Expand the use: Consider additional use cases and user types who might benefit from accurate sub-address data.
3. Build data pipelines: Avoid data siloes and duplicative efforts by partnering with organizations who may already be maintaining sub-addresses for your community. Planning and zoning departments, utilities, addressing authorities, or third party vendors may have data they can share.

Sub-Addressing Best Practices

Because sub-addresses are not required in any NENA standards, those looking to take on this task have some freedom to curate sub-addresses that suit their needs. There is no single best way to assign sub-addresses. Instead, there are several best practices that stakeholders can follow to ensure optimal outcomes for all parties involved.

Stay Organized

To avoid clutter in datasets, separate the main address point from sub-addresses. Stacking sub-addresses at a single ingress egress point is also possible, but is sub-optimal for first responders.

Label Notable Structures

When sub-addressing multi-structure complexes with a single address, name notable areas as structures, i.e. “ball field” in the image above.

Consider Necessary Details

The granularity of this data is determined by its author. Consider usability and interoperability when deciding which details to include.

Maintenance Is Key

Ensure that this information is updated regularly by instating a process for when sub-addresses change due to construction, owner changeover, etc..

Placement Of Stacked Sub-Addresses

Sub-addresses in multi-story buildings can quickly become messy. Avoid this by incorporating Z-values into your workflows.

Create Logical Naming Conventions

Hotels with absent 13th floors and colloquially named buildings on college campuses can be nightmarish for first responders and dispatchers. Logical naming conventions allow personnel who have never visited these locations to easily navigate to incidents. 

Adopting a standard procedure for sub-addressing can help alleviate pain points for a number of industries that rely on the accuracy and completeness of this information to perform optimally. Incorporating data related to detail, placement, and regular maintenance into sub-addressing workflows will ensure interoperability and accessibility for those who rely on this information when seconds matter most. To learn more about sub-addressing best practices and solutions to improve standard procedures, contact our team.

Reference Materials and standards: NENA Information Document for Development of Site/Structure Address Point GIS Data for 9-1-1, NENA Requirements for 3D Location Data for E9-1-1 and NG9-1-1