GridMap< StateT, T > Class Template Reference

A grid map for spatial representation, navigation, and planning. More...

#include <GridMap.h>

Inheritance diagram for GridMap< StateT, T >:

Collaboration diagram for GridMap< StateT, T >:

Classes
struct	Cell
	Cell structure to represent grid cell indices. More...

Public Member Functions
	GridMap ()=default
	Default constructor.
	GridMap (int xCount, int yCount, DistanceM resolutionM)
	Construct with cell counts and resolution in meters.
	GridMap (int xCount, int yCount, Distance resolution)
	Construct with cell counts and Distance object for resolution.
bool	worldToCell (DistanceM wx, DistanceM wy, Cell &cell) const
	World to cell conversion.
void	cellToWorld (int cx, int cy, DistanceM &wx, DistanceM &wy) const
	Cell to world (center of cell)
Coordinate< DistanceM >	toWorld (int cx, int cy) const
	Provide the workd coordinates for the cell.
bool	getCell (int cx, int cy, StateT &result)
	Provide access to cell state by cell index.
bool	getCell (int cx, int cy, CellState &result) const
	Provide access to cell state by cell index.
bool	getCell (Coordinate< T > &coord, CellState &result)
	Provide access to cell state by coordinate.
void	setCell (Cell &cell, CellState value)
	Provide access to cell state by coordinate.
void	setCell (int cx, int cy, CellState value)
	Set cell state (for initialization or manual updates)
void	setCell (Coordinate< T > &coord, CellState value)
	Set cell state by coordinate (converts to cell index internally)
std::vector< Cell >	getNeighborCells (const Coordinate< DistanceM > from) const
	Determine all neighboring cells (8-connected) for a given cell coordinate.
std::vector< Coordinate< T > >	getNeighbors (Coordinate< T > from) const
	Get world coordinates of neighboring cells (for pathfinding or navigation)
void	resize (int newXCount, int newYCount)
	Resize the grid to new dimensions.
int	getXCount () const
	Get the number of cells in the x direction.
int	getYCount () const
	Get the number of cells in the y direction.
float	getResolution () const
	Get the cell resolution in meters.
void	setResolution (float resM)
	Defines the resolution in meters.
bool	isValid (const Coordinate< T > &coord) const
	Check if a coordinate is within the map bounds.
void	setCellStateCallback (CellState(*cb)(const StateT &, void *ref))
	Set the callback for converting StateType to CellState.
void	setValidityCallback (bool(*cb)(int cx, int cy, void *ref))
	Set the callback for cell validity checking.
void	setReference (void *ref)
	Set the reference pointer passed to callbacks.
size_t	writeTo (Print &out)
	Write map to output.
size_t	readFrom (Stream &in)
	Read map from input.
virtual int	getXCount () const =0
	Get the number of cells in the X direction.
virtual int	getYCount () const =0
	Get the number of cells in the Y direction.
virtual float	getResolution () const =0
	Get the map resolution (cell size in meters).
virtual bool	getCell (int x, int y, CellState &state) const =0
	Get the state of a cell by integer indices.
virtual Coordinate< T >	toWorld (int x, int y) const =0
	Convert cell indices to world coordinates.
virtual std::vector< Coordinate< T > >	getNeighbors (Coordinate< T > from) const =0
	Get world coordinates of neighboring cells (for pathfinding or navigation).
virtual bool	isValid (const Coordinate< T > &coord) const =0
	Check if a coordinate is inside the map bounds.

Static Protected Member Functions
static bool	isValid (int cx, int cy, void *ref)

Protected Attributes
int	xCount = 0
int	yCount = 0
float	resolution = 0
Coordinate< T >	origin
void *	reference = this
bool(*	is_valid_cb )(int cx, int cy, void *) = isValid
CellState(*	get_cellstate_cb )(const StateT &, void *ref) = nullptr
std::vector< StateT, AllocatorPSRAM< StateT > >	data
GridMapSerializer< GridMap< StateT >, StateT, T >	serializer

Detailed Description

template<typename StateT = CellState, typename T = DistanceM>
class tinyrobotics::GridMap< StateT, T >

A grid map for spatial representation, navigation, and planning.

The GridMap class models the environment as a regular grid of cells, each storing a state (e.g., occupancy, height, or other user-defined data). It supports:

• Conversion between world coordinates and grid cell indices
• Efficient cell state access and modification
• Binary Bayesian updates for probabilistic occupancy mapping
• Custom cell validity logic (e.g., for dynamic obstacles)
• Extraction of valid neighbor cells for pathfinding (8-connected)

Typical use cases include:

• Robot navigation and path planning
• Occupancy grid mapping (SLAM)
• Environment modeling for simulation or AI

Features:

• Template parameter for cell state type (e.g., occupancy, height)
• World-to-cell and cell-to-world coordinate conversion
• Fast access to cell state by index or coordinate
• Probabilistic update using log-odds for sensor fusion
• Customizable cell validity via callback (see setValidityCallback)
• Customizable cell state conversion via callback (see setCellStateCallback)
• Neighbor cell extraction for graph-based search

Callback Notes:

• Validity Callback: Use setValidityCallback to provide custom logic for determining if a cell is valid (e.g., for dynamic obstacles or special terrain). The callback receives cell indices and an optional reference pointer.
• Cell State Callback: Use setCellStateCallback to provide custom logic for converting StateType to CellState (e.g., for visualization or compatibility with algorithms expecting CellState). The callback receives the cell value and an optional reference pointer.
• Use setReference to set the reference pointer passed to both callbacks.

Example:

GridMap<CellState> map(100, 100, 0.1f); // 10m x 10m, 10cm resolution
Coordinate<float> pos(1.2, 3.4);
map.setCell(pos, CellState::OCCUPIED);
auto state = map.getCell(5, 5);
 
// For GridMap<float>, set a callback to convert float to CellState
map.setCellStateCallback([](const float& v, void*) {
  return v > 0.5f ? CellState::OCCUPIED : CellState::FREE;
});

Template Parameters

StateType	The type stored in each cell (e.g., occupancy, height)
T	Numeric type for coordinates (default: float)

Member Function Documentation

getCell()

bool getCell ( int  cx, int  cy, CellState &  result  ) const

inlinevirtual

Provide access to cell state by cell index.

Implements IMap< T >.

getNeighbors()

std::vector< Coordinate< T > > getNeighbors ( Coordinate< T >  from ) const

inlinevirtual

Get world coordinates of neighboring cells (for pathfinding or navigation)

Implements IMapNeighbors< T >.

getResolution()

float getResolution ( ) const

inlinevirtual

Get the cell resolution in meters.

Implements IMap< T >.

getXCount()

int getXCount ( ) const

inlinevirtual

Get the number of cells in the x direction.

Implements IMap< T >.

getYCount()

int getYCount ( ) const

inlinevirtual

Get the number of cells in the y direction.

Implements IMap< T >.

isValid() [1/2]

bool isValid ( const Coordinate< T > &  coord ) const

inlinevirtual

Check if a coordinate is within the map bounds.

Parameters

coord

The coordinate to check.

Returns

true if the coordinate is inside the map, false otherwise.

Implements IMapNeighbors< T >.

isValid() [2/2]

static bool isValid ( int  cx, int  cy, void *  ref  )

inlinestaticprotected

Default validity check: a cell is valid if it's not occupied. This can be overridden with a custom callback for more complex logic (e.g., dynamic obstacles, special terrain, etc.).

toWorld()

Coordinate< DistanceM > toWorld ( int  cx, int  cy  ) const

inlinevirtual

Provide the workd coordinates for the cell.

Implements IMap< T >.

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The documentation for this class was generated from the following file:

• src/TinyRobotics/maps/GridMap.h