Grid

A 2D grid of data

Panel support

Grid is used in the 3D and Image panels.

Schema

field	type	description
timestamp	Timestamp	Timestamp of grid
frame_id	string	Frame of reference
pose	Pose	Origin of grid's corner relative to frame of reference; grid is positioned in the x-y plane relative to this origin
column_count	uint32	Number of grid columns
cell_size	Vector2	Size of single grid cell along x and y axes, relative to pose
row_stride	uint32	Number of bytes between rows in data
cell_stride	uint32	Number of bytes between cells within a row in data
fields	PackedElementField[]	Fields in data. red, green, blue, and alpha are optional for customizing the grid's color.
data	bytes	Grid cell data, interpreted using fields, in row-major (y-major) order.

fields

To enable RGB color visualization in the 3D panel, include all four of these fields in your fields array:

• red - Red channel value
• green - Green channel value
• blue - Blue channel value
• alpha - Alpha/transparency channel value

note: All four fields must be present with these exact names for RGB visualization to work. The order of fields doesn't matter, but the names must match exactly.

Recommended type: UINT8 (0-255 range) for standard 8-bit color channels.

Example field definitions:

RGB color only:

fields: [
 { name: "red", offset: 0, type: NumericType.UINT8 },
 { name: "green", offset: 1, type: NumericType.UINT8 },
 { name: "blue", offset: 2, type: NumericType.UINT8 },
 { name: "alpha", offset: 3, type: NumericType.UINT8 },
];

RGB color with elevation (for 3D terrain visualization):

fields: [
 { name: "red", offset: 0, type: NumericType.UINT8 },
 { name: "green", offset: 1, type: NumericType.UINT8 },
 { name: "blue", offset: 2, type: NumericType.UINT8 },
 { name: "alpha", offset: 3, type: NumericType.UINT8 },
 { name: "elevation", offset: 4, type: NumericType.FLOAT32 },
];

When these fields are present, the 3D panel will offer additional "Color Mode" options including "RGBA (separate fields)" to visualize the RGB data directly. For elevation visualization, set the "Elevation field" to your elevation layer name.

data

For the data element starting at byte offset i, the coordinates of its corner closest to the origin will be:

• y = i / row_stride * cell_size.y
• x = (i % row_stride) / cell_stride * cell_size.x

Reference implementations

Foxglove schemas are framework-agnostic, and can be implemented using any supported message encoding:

encoding	schema
ROS 1	foxglove_msgs/Grid
ROS 2	foxglove_msgs/msg/Grid
JSON	foxglove.Grid
Protobuf	foxglove.Grid
FlatBuffers	foxglove.Grid
OMG IDL	foxglove::Grid

You must use the schema names specified above for Foxglove to recognize the schema.