CoordinateSpace

Usage & Examples

One common use for this class may be to convert from a standard ENU format into cartesian format for later calculation purposes. In this case, you could create a coordinate space and perform a transform like so (assuming no rotation transform):

//Create a coordinate space with SIMPLE_CARTESIAN.
auto coordinateSystem = CoordinateSpace(CoordinateSystem::SIMPLE_CARTESIAN);

//Perform a transform.
auto enuVector = Sample3D(32, 14, 55);
auto simpleCartesianVector = coordinateSystem.transform(enuVector);

Methods

CoordinateSpace(CoordinateSystem, …)

CoordinateSpace(CoordinateSystem system, bool upsidedown = false, int rotated = COORDINATE_SPACE_ROTATED_0);

Creates a coordinate space of the given coordinate system, optionally making the system flipped or rotated.

Parameters
- coordinateSystem (CoordinateSystem): The coordinate system that this coordinate space uses.
- upsidedown (bool, optional): Whether this coordinate space should be flipped vertically.
- rotated (int, optional): The rotation of the sensor on the PCB. Defines pin 1 as the top left corner. Does not represent an angle, only valid values are defined as COORDINATE_SPACE_ROTATED_*.

transform(Sample3D)

Sample3D transform(Sample3D s);

Transforms a given Sample3D in ENU format into the format defined in this coordinate space.

Parameters
- s (Sample3D): The ENU format sample to convert into this coordinate space.

transform(Sample3D, CoordinateSystem)

Sample3D transform(Sample3D s, CoordinateSystem system);

Transforms a given Sample3D in ENU format into the format defined in the supplied CoordinateSystem system.

Parameters
- s (Sample3D): The ENU format sample to convert into this coordinate space.
- system (CoordinateSystem): The coordinate system to output in.

Returns - The equivalent location of the provided sample s in the current CoordinateSpace, in the format of the provided CoordinateSystem system.

Members

system

CoordinateSystem system;

The CoordinateSystem this coordinate space uses to output transformed samples.

upsidedown

bool upsidedown;

Whether this coordinate system is vertically flipped or not.

rotated

int rotated;

The rotation of this coordinate system, based on the rotation of the sensor on the PCB, defining pin 1 as the top left corner. Does not represent an angle, and defines valid values as COORDINATE_SPACE_ROTATED_*, like so:

#define COORDINATE_SPACE_ROTATED_0      0
#define COORDINATE_SPACE_ROTATED_90     1
#define COORDINATE_SPACE_ROTATED_180    2
#define COORDINATE_SPACE_ROTATED_270    3

Structs

Sample3D

Represents a single three dimensional vector. Defines operator overloads for equality and addition/subtraction.

struct Sample3D
{
    int x;
    int y;
    int z;

    Sample3D();
    Sample3D(int x, int y, int z);
    float dSquared(Sample3D &s);

    Sample3D operator-(const Sample3D& other) const;
    Sample3D operator+(const Sample3D& other) const;
    bool operator==(const Sample3D& other) const;
    bool operator!=(const Sample3D& other) const;
};

Enumerations

CoordinateSystem

The types of coordinate system available to the accelerometer.

enum CoordinateSystem
{
    RAW,
    SIMPLE_CARTESIAN,
    NORTH_EAST_DOWN,
    EAST_NORTH_UP,
    NORTH_EAST_UP = EAST_NORTH_UP, //For legacy compatibility.
};

To make this easier to visualise, the below diagram demonstrates the orientation and direction of the axes with each of these values.

Simple Cartesian	North East Down

Class Definition

class CoordinateSpace
{
    public:
        CoordinateSystem    system;
        bool                upsidedown;
        int                 rotated;

        CoordinateSpace(CoordinateSystem system, bool upsidedown = false, int rotated = COORDINATE_SPACE_ROTATED_0);
        Sample3D transform(Sample3D s);
        Sample3D transform(Sample3D s, CoordinateSystem system);

};