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manual:user_guide:tools:altitude [2015/04/02 14:04] – mstupka | manual:user_guide:tools:altitude [2016/10/21 16:04] – [Pressure sensor] mstupka | ||
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- | ====== Altitude Manager ====== | + | {{ : |
---- | ---- | ||
===== About ===== | ===== About ===== | ||
+ | <wrap box>Menu > Settings > GPS and location > Altitude manager</ | ||
+ | |||
Altitude manager enables to fine-tune obtaining altitude values from your mobile device. It is divided into three main tabs: | Altitude manager enables to fine-tune obtaining altitude values from your mobile device. It is divided into three main tabs: | ||
* **main settings** | * **main settings** | ||
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* **settings of pressure sensor** | * **settings of pressure sensor** | ||
===== Settings ===== | ===== Settings ===== | ||
+ | {{ : | ||
==== Altitude offset ==== | ==== Altitude offset ==== | ||
- | * **Use altitude offset** - switches on the definition of offset between real and GPS altitude. More in the **Offset tab**. | + | * **Use altitude offset** - switches on the definition of offset between real and GPS altitude. More in the **[[manual: |
==== Pressure sensor ==== | ==== Pressure sensor ==== | ||
- | * **Use pressure sensor** - switches on measuring precise altitude by the device built-in barometric pressure sensor. More in the **Pressure tab**. | + | * **Use pressure sensor** - switches on measuring precise altitude by the device built-in barometric pressure sensor. More in the **[[manual: |
==== Elevation data ==== | ==== Elevation data ==== | ||
- | * **Optimize GPS altitude** - uses [[http:// | + | * **Optimize GPS altitude** - uses [[http:// |
<WRAP round alert > | <WRAP round alert > | ||
**Warning for pilots**: this method is not recommended for activities when you are **not moving on the ground** - displayed altitude values are influenced by the ground altitude measuring and calculation | **Warning for pilots**: this method is not recommended for activities when you are **not moving on the ground** - displayed altitude values are influenced by the ground altitude measuring and calculation | ||
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===== Offset ===== | ===== Offset ===== | ||
- | Altitude calculated by internal GPS unit is related to a different method of referencing the Earth surface than that used in maps. The difference between them is called **Geoid height** which is distance between [[http:// | + | {{ : |
+ | Altitude calculated by internal | ||
Locus Map can define this offset by three methods: | Locus Map can define this offset by three methods: | ||
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* **Altitude NMEA correction** - mobile device communicates with GPS unit over a special messages called NMEA. These messages contain values of Geoid height that Locus Map can read and apply them to correct this offset.< | * **Altitude NMEA correction** - mobile device communicates with GPS unit over a special messages called NMEA. These messages contain values of Geoid height that Locus Map can read and apply them to correct this offset.< | ||
===== Pressure Sensor ===== | ===== Pressure Sensor ===== | ||
+ | {{ : | ||
Some devices are equipped with barometric pressure sensor. Barometric sensors measure atmospheric pressure very precisely which can be used for calculating relative altitude changes. I.e. if you know certain pressure at certain altitude you can calculate altitude changes between known and current position. | Some devices are equipped with barometric pressure sensor. Barometric sensors measure atmospheric pressure very precisely which can be used for calculating relative altitude changes. I.e. if you know certain pressure at certain altitude you can calculate altitude changes between known and current position. | ||
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* **Automatic** - Locus Map uses GPS altitude or SRTM files altitude and current barometric pressure as basic values and relates all other measurements to these values. It also checks measured values in 2 hour intervals and eventually re-calibrates the pressure sensor.< | * **Automatic** - Locus Map uses GPS altitude or SRTM files altitude and current barometric pressure as basic values and relates all other measurements to these values. It also checks measured values in 2 hour intervals and eventually re-calibrates the pressure sensor.< | ||
* **Pressure at sea level** - current pressure value at a particular sea level as the reference can be obtained from the Internet. The resulting altitude calculation is also quite accurate but the base pressure changes in time so it can be a problem. | * **Pressure at sea level** - current pressure value at a particular sea level as the reference can be obtained from the Internet. The resulting altitude calculation is also quite accurate but the base pressure changes in time so it can be a problem. | ||
- | * Altitude - uses some other source of ground altitude - external maps, measuring, tourist guide posts, etc. as the reference. Locus Map then calibrates the pressure sensor according to this value. | + | |
< | < | ||
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</ | </ | ||