Questions
How is the Qibla direction calculated?
It is the great circle bearing from your position to the Kaaba in Mecca (21.4225° N, 39.8262° E): the direction of the shortest path over the Earth, measured clockwise from true north.
Why does the Qibla point northeast from North America?
On a globe the shortest route from the United States or Canada to Mecca crosses the North Atlantic, so the bearing is northeast, not the southeast a flat map suggests.
How accurate is the compass arrow?
It follows your phone's compass, which points to magnetic north and can be thrown off by magnets and metal nearby. Move the phone in a figure 8 to calibrate it, and keep in mind that magnetic north can differ from true north by several degrees.
Can I use it without sharing my location?
Yes. Pick a city from the list. The direction is then the one from that city, so the farther you are from it, the less exact it is.