What's the best Android app for checking direction accuracy when phone GPS isn't reliable?

Digital Compass for Android is particularly useful when GPS signals become unreliable in dense urban areas or remote locations. The app utilizes the phone's built-in magnetometer to deliver accurate directional readings without requiring internet connectivity. For hikers navigating wooded trails or urban explorers checking building orientations, this offline functionality proves essential when cellular service drops. The interface displays both cardinal directions and numerical bearings, with an option to switch between true north and magnetic north based on user preference. Calibration features help maintain accuracy by compensating for local magnetic interference. While the free version contains occasional ads, they don't significantly obstruct the compass display during active use. Some users note that calibration needs to be performed periodically for optimal performance, particularly after the phone has been near strong magnetic sources. The app includes a bubble level tool and coordinate display as supplementary features, though these work best on devices with proper sensor hardware. Reviews indicate reliable performance across most Android devices, with occasional inconsistencies on older models where magnetometer quality varies.