CorrectAltitude vs Altitude Measurement

Correct Altitude establishes your position using data from at least twelve GPS satellites. This app shows the altitude at your current location, and enables you to take altitude-and-date-stamped photographs. Hikers usually turn off their iPhones on mountain trails because of the poor signal. When turned on, the iPhone GPS will try to determine the current location with data from three GPS satellites; however, these co-ordinates are still inaccurate. CorrectAltitude triangulates position with a large number of GPS satellites in a 5-minute period enabling an accurate determination of altitude. The app automatically continues triangulating position by polling GPS satellites, and informs you when it has established a location accurate to within the tolerated range of error. The default for this range is 5 meters (approximately 16 feet). As an add-on function, it can display where you are (if the place has a name), and this can be useful for contacting rescue services in emergencies. CorrectAltitude has been tested on hiking trails in the Himalayas! Here is an example of an altitude-and-date-stamped photograph. The photograph is taken at the maximum resolution of your phone's camera and stored. GPS information is discarded. If the Notify mode remains set to "ON", you will continue to get updates on altitude every five minutes. To conserve the battery and stop repeated updates, you may prefer to set Notify mode to "OFF" after you have determined your altitude.

Altitude Measurement shows the ground elevation of the spot under the map crosshair, instantly. In Japan, it also lets you see hazard maps and a flood simulation on the same map. ELEVATION AT A GLANCE - Move the map and the elevation under the crosshair updates - Japan uses high-precision data from the Geospatial Information Authority of Japan (down to a 1 m mesh); elsewhere it uses worldwide elevation data - Tap the location button to compare the ground elevation with the altitude your device measures - Switch between meters and feet - Search by address or place name; switch between standard and satellite maps DISASTER PREPAREDNESS (JAPAN) - Overlay hazard maps for river flooding, inland flooding, storm surge, tsunami, landslides and flood duration - Show up to two layers at once and adjust their opacity - A legend in the official colors always stays on the map - "Shinsui Navi" shows what could happen if a nearby river breaks its banks: maximum flood depth, time until flooding starts, and a graph of depth over time FAVORITES - Save places you use often, with their name and elevation - Sync them between your own iPhone, iPad and Mac through iCloud EASY TO USE - iPhone shows the map with a card; iPad adds a sidebar for a roomier layout - Supports Dark Mode, larger text and VoiceOver - 14 languages: Japanese, English, Korean, Chinese (Simplified and Traditional), German, French, Spanish, Italian, Portuguese (Brazil), Dutch, Polish, Turkish and Russian - Share an elevation, or open a place from a shortcut with an altitude:// link LOCATION AND PRIVACY Your location is used only when you tap the location button, never just because the app launched. To look up an elevation, the app sends only map tile numbers, not your exact position. ADS The app is free. To keep it running, it shows an ad at the bottom of the screen. In Settings you can watch a short video ad to the end and hide ads for the rest of the day. ■ Data sources Elevation: GSI elevation tiles (Japan); AWS Terrain Tiles elsewhere (USGS 3DEP, SRTM, GMTED2010, NOAA ETOPO1 and others) Hazard maps: Hazard Map Portal Site, Ministry of Land, Infrastructure, Transport and Tourism (GSI tiles) Shinsui Navi: GSI flood simulation Credits also appear in the in-app map legend, the disaster screen and Settings > Data Sources. ■ Please note - Elevations are reference values derived from public data such as the Geospatial Information Authority of Japan (GSI). Do not rely on this app alone for surveying, climbing or evacuation decisions. - Hazard maps and the flood simulation (Shinsui Navi) appear only in Japan. They show assumed scenarios, not a guarantee of actual damage. Check your local government and official national sources for the latest information. - No account or sign-in is required.