Scientific American provides a fascinating introduction to how GPS devices work.
"The Global Positioning System (GPS) consists of 24 operating satellites and several spares. Some of these spare satellites are also in use or can readily be activated once an operating satellite becomes dysfunctional. Taking the specific orbits of this many satellites into consideration, an observer can see at least four satellites at any time from any location on the earth."
Thanks to Chris Steins
FULL STORY: How do GPS devices work?

Planetizen Federal Action Tracker
A weekly monitor of how Trump’s orders and actions are impacting planners and planning in America.

Maui's Vacation Rental Debate Turns Ugly
Verbal attacks, misinformation campaigns and fistfights plague a high-stakes debate to convert thousands of vacation rentals into long-term housing.

Restaurant Patios Were a Pandemic Win — Why Were They so Hard to Keep?
Social distancing requirements and changes in travel patterns prompted cities to pilot new uses for street and sidewalk space. Then it got complicated.

In California Battle of Housing vs. Environment, Housing Just Won
A new state law significantly limits the power of CEQA, an environmental review law that served as a powerful tool for blocking new development.

Boulder Eliminates Parking Minimums Citywide
Officials estimate the cost of building a single underground parking space at up to $100,000.

Orange County, Florida Adopts Largest US “Sprawl Repair” Code
The ‘Orange Code’ seeks to rectify decades of sprawl-inducing, car-oriented development.
Urban Design for Planners 1: Software Tools
This six-course series explores essential urban design concepts using open source software and equips planners with the tools they need to participate fully in the urban design process.
Planning for Universal Design
Learn the tools for implementing Universal Design in planning regulations.
Heyer Gruel & Associates PA
JM Goldson LLC
Custer County Colorado
City of Camden Redevelopment Agency
City of Astoria
Transportation Research & Education Center (TREC) at Portland State University
Jefferson Parish Government
Camden Redevelopment Agency
City of Claremont