Software Sharing Models

August 3, 2020 | By Waldo Jaquith

We started the State Software Collaborative to facilitate sharing open source software between states, but the idea of governments sharing software is hardly novel. Governments around the world are sharing custom-built software already, and have done so for many years. It’s vital, cost-saving, and meets the needs of users.

Software can be shared via many different models. Here are a few examples that run the gamut, ranging from the deliberate and parochial clear to the incidental and popular.

Tax Appraisal Software

An important source of revenue for localities throughout the U.S. are taxes on real estate, and many have a similar tax on vehicles. Those taxes are on the current value of the property, which means that states and localities need to routinely reappraise the value of everything that they tax — every parcel of land, every car, every RV, every house. This means that every state has to maintain their own database of every taxable property — this “computer-assisted mass appraisal” software (or “CAMA”) has been around for decades, and there are several major vendors selling CAMA software.

But Georgia didn’t go the commercial route. In the late 1980s, before CAMA software was commonplace, Georgia wanted to modernize, but didn’t see a lot of options. So the Georgia Department of Revenue collaborated with the Tennessee Valley Authority and a Mississippi professor to build their own software to track the value of taxable property. They did this on a budget of just $20,000 ($43,000 in 2020 dollars), and in 1989 they deployed their Georgia Appraisal Program to 12 counties. The state continued to support the project for several years, in the form of technical staffing. They’ve evolved the software over the decades, and today the software travels under the name of WinGAP CAMA. This Windows-based software includes client software, runs on the desktop, and relies on a SQL Server back end. Every member county runs their own copy of the software with their own server.

screenshot of WinGAP CAMA data entry screen
Screenshot of WinGAP CAMA data entry screen.

Today, WinGAP CAMA is in use by 149 of Georgia’s 159 counties (the Atlanta metropolitan area uses commercial software) who collectively make up the membership of the GAP Group, a non-profit organization governed by a small executive board. Every member county pays modest dues of $1,500/year, which gets them both the software and access to the help desk. That $223,500 in annual dues — plus a state-operated help desk — is enough to fund everything.

The GAP Group attributes their success to their iterative development model and their relentless focus on the needs of end users. Going strong after 31 years, they’re a model of the value of user-centered design.

Public Transit Route Planning

Large cities need multimodal trip planning software — websites where people can plan travel via light rail, bus, bike share, etc. In 2009, there were three open source software programs that did portions of this. So TriMet, Portland OR’s transit agency, brought the creators of those programs together and persuaded them to collaborate, funded with a grant from Portland’s Metropolitan Planning Organization.

Two years later, the result was OpenTripPlanner, an independent, open source project that can be used by any transit agency to provide a public route-planning website.

Screenshot of Portland, OR TriMet Trip Planner
Screenshot of Portland, OR TriMet Trip Planner.

Today, the developers who created OpenTripPlanner have created a consultancy named Conveyal, where they continue to support OpenTripPlanner development.

The Java-based tool runs on a web server, consuming data feeds of routes and schedules. Over 100 people have contributed to the code in the past decade.

OpenTripPlanner isn’t a TriMet project. Its creation was fomented by TriMet, but today it’s used around the world, including by TriMet, and by New York and Vermont. The project has a documented governance process, with a project leadership committee that includes representatives from transit agencies around the world.


Every government in the U.S. needs detailed maps, so they can track parcel ownership, where their water pipes are, the locations of their sidewalks and roads, even where every government-owned tree is. These are called Geographic Information Systems, and they can be enormously expensive.

And then there’s QGIS. This open source program was developed by Gary Sherman in 2002, and graduated to being housed by the Open Source Geospatial Foundation starting in 2007, and reached a version 1.0 milestone in 2009. As desktop software, it runs on Linux, macOS, Windows.

It’s a true community project — features have been contributed by hundreds of people over many years. But QGIS is essential to government, too — not only is it widely used at all levels of government throughout the world, but governments actively contribute to the advancement of the software.

Screenshot of QGIS Map
Screenshot of QGIS Map.

For example, sponsors of QGIS include Ireland’s Office of Public Works; the state of Vorarlberg, Austria; the municipality of Syddjurs, Denmark, Bathurst Regional Council, Australia; the Tasmanian Planning Commission; and City of Canning, Australia.

Governments also contribute to QGIS by sponsoring new features — paying to add functionality that they need. For example, the town of Megéve, France funded a new trim/extend feature, and the canton of Zug, Switzerland funded JSON support for GeoPackage files. By covering the development costs, Megéve and Zug got the functionality that they needed, but so did everybody else who uses QGIS.

It’s important to agencies that they be able to call somebody when their software breaks, and that sort of support is available for QGIS, via the dozens of private vendors that sell support contracts, many of whom are also contributors to QGIS.

QGIS did not originate with government, and it does not live within government now. But it is nonetheless software relied on by governments, shared between governments, and contributed to by governments, via mechanisms that exist entirely outside of government.


Intergovernmental software sharing is not new — as we can see here, this practice is decades old, quietly powering government right under our noses. There are different sharing models that make sense for different types of software, and these mature projects have all found the model that works for them.

This powerful, effective approach to software production and maintenance is a top-tier method of procuring software within government, at a cost 10–100 times cheaper than traditional methods of software procurement. Before they write a solicitation, agencies would be wise to research whether there is an existing shared software product they can use, or if they could team up with other agencies to share the cost of procuring software to address their collective needs.


Waldo Jaquith is a fellow at the Beeck Center for Social Impact + Innovation and the co-founder of the State Software Collaborative. Follow him at @waldojaquith.