
## Measurement
There are two measurements systems used interchangeably: 1) Gauss and 2) microTelsas. The equivalency is:
     1 G = 10−4 T = 100 μT (microtesla).

Example:
    Strength of Earth's magnetic field at 0° latitude, 0° longitude: 3.2×10−5 T (31.869 μT)
    Strength of a typical refrigerator magnet: 5×10−3 T (5 mT)

### Gauss (deprecated)
The gauss (symbol: G, sometimes Gs) is a unit of measurement of magnetic flux density, B (also known as magnetic induction or magnetic field). This system of measurement has been superceded by the metric system (see below), but it remain used in various fields and documents today, so it is important to realize Gauss is the older system replaced by the metric system.

Real world examples: the Earth's magnetic field at its surface 0.25–0.60 G 

### microTeslas (current metric)
The tesla (symbol: T) is the unit of magnetic flux density (also called magnetic B-field) in the International System of Units (SI).  The abbreviation SI (from French *Système international d'unités*), is the modern form of the **metric system** and the world's most widely used system of measurement.  https://en.wikipedia.org/wiki/International_System_of_Units.

Source: https://en.wikipedia.org/wiki/Tesla_(unit)

The microtesla is 1/1,000,000, or a millionth, of a tesla.

1 tesla is a very strong force.  Real world examples: a coil gap of a typical loudspeaker magnet is  1 T to 2.4 T or the strength of medical magnetic resonance imaging (aka "MRI") systems is 1.5 T to 3 T.

Note different units which can appear similar: "m" vs. "μ"

     T      tesla 
     mT 	millitesla [thousandth] = 10−3 T or 1/1000th of a tesla 	
     μT 	microtesla [millionth] = 10−6 T or 1/1000th of a millitesla

## QMIC6310U
The Magnetometer installed of the T-Beam SUPREME is the QMC6310U manufactured by QST Corporation (Shanghai, China). QMC6310 is a three-axis magnetic sensor combined with an Application-Specific Integrated Circuit ("ASIC") that:

    amplifies extremely small sensor signals
    filters noise
    converts analog signals → digital (ADC)
    applies internal scaling and conditioning
    formats data for I²C output

Not only does it measure raw magnetic fields for X,Y & Z, it then produces a 16 bit value that can be transmitted over the I²C line.  All of this is performed in one silicon chip inside a "package" of 1.2mm (Length)*1.2mm (Width)*0.53mm (Height).  1°to 2°compass heading accuracy can be achieved by this chip with calibration.
### Modes
The chip can be configured into a variety of resolution modes.  It will always produce a 16 signed integer and by setting the MagFullScaleRange, you can specify full-scale measurement range you are sampling.  For example, FS_8G samples over a range of -8 G → +8 G, whereas FS_2G samples over a range of -2 G → +2 G.  So the smaller the range, the higher the precision.  If you were in a room with an MRI, FS_2G will clipp because there probably would be values in excess of +/-2 Gauss.  But, if you are outside and free of metal and potential distortions, the FS_2G would give you the most accurate result.