Dimensions

All point data in PDAL is stored as a set of dimensions. Dimensions have a name and a data type. The data type is determined at runtime, but a default data type for each dimension is listed below, along with the name of the dimension and its description.

The following table provides a list of known dimension names you can use in Filters, Writers, and Readers.

Note

Types are default types. Stage developers should set the dimension type explicitly if the default dimension isn’t suitable.

Name	Type	Description
Alpha	uint16	Alpha
Amplitude	float	This is the ratio of the received power to the power received at the detection limit expressed in dB
Anisotropy	double	Anisotropy of a point; larger values indicate strong variance in multiple dimensions.
Azimuth	double	Scanner azimuth
BackgroundRadiation	float	A measure of background radiation.
Blue	uint16	Blue image channel value
ClassFlags	uint8	Class Flags
Classification	uint8	ASPRS classification. 0 for no classification. See LAS specification for details.
ClusterID	int64_t	ID assigned to a point by a point-clustering algorithm.
Curvature	double	Curvature of surface at this point
DemantkeVerticality	double	Verticality of a point; larger values indicate vertical structure (Demantke’s variation).
Density	double	Estimate of point density
Deviation	float	Difference between the shape of the reference pulse and the return pulse. A larger value for deviation indicates larger distortion.
EchoRange	double	Echo Range
EdgeOfFlightLine	uint8	Indicates the end of scanline before a direction change with a value of 1 - 0 otherwise
Eigenentropy	double	Eigenentropy of a point; small values indicate more ordered regions, while large values indicate disorder.
EigenvalueSum	double	Sum of computed eigenvalues.
ElevationCentroid	double	Elevation Centroid
ElevationHigh	double	Elevation High
ElevationLow	double	Elevation Low
Flag	uint8	Flag
GpsTime	double	GPS time that the point was acquired
Green	uint16	Green image channel value
HeightAboveGround	double	Height Above Ground
Infrared	uint16	Infrared
Intensity	uint16	Representation of the pulse return magnitude
InternalTime	double	Scanner’s internal time when the point was acquired, in seconds
IsPpsLocked	uint8	The external PPS signal was found to be synchronized at the time of the current laser shot.
LatitudeCentroid	double	Latitude Centroid
LatitudeHigh	double	Latitude High
LatitudeLow	double	Latitude Low
Linearity	double	Linearity of a point; larger values indicate more linear regions.
LongitudeCentroid	double	Longitude Centroid
LongitudeHigh	double	Longitude High
LongitudeLow	double	Longitude Low
LvisLfid	uint64	LVIS_LFID
Mark	uint8	Mark
NNDistance	double	Distance metric related to a point’s nearest neighbors.
NormalX	double	X component of a vector normal to surface at this point
NormalY	double	Y component of a vector normal to surface at this point
NormalZ	double	Z component of a vector normal to surface at this point
NumberOfReturns	uint8	Total number of returns for a given pulse.
OffsetTime	uint32	Milliseconds from first acquired point
Omit	uint8_t	Used to shallowly mark a point as being omitted without removing it
Omnivariance	double	Omnivariance of a point; cube root of the product of all eigenvalues.
OptimalKNN	uint64	Optimal number of k nearest neighbors, such that eigenentropy is minimized.
OptimalRadius	double	Radius corresponding to optimal k nearest neighbors, such that eigenentropy is minimized.
OriginId	uint32	A file source ID from which the point originated. This ID is global to a derivative dataset which may be aggregated from multiple files.
PassiveSignal	int32	Relative passive signal
PassiveX	double	Passive X footprint
PassiveY	double	Passive Y footprint
PassiveZ	double	Passive Z footprint
Pdop	float	GPS PDOP (dilution of precision)
Pitch	float	Pitch in degrees
Planarity	double	Planarity of a point; larger values indicate more planar regions.
PointId	uint32	An explicit representation of point ordering within a file, which allows this usually-implicit information to be preserved when reordering points.
PointSourceId	uint16	File source ID from which the point originated. Zero indicates that the point originated in the current file
PulseWidth	float	Laser received pulse width (digitizer samples)
Red	uint16	Red image channel value
Reflectance	float	Ratio of the received power to the power that would be received from a white diffuse target at the same distance expressed in dB. The reflectance represents a range independent property of the target. The surface normal of this target is assumed to be in parallel to the laser beam direction.
ReflectedPulse	int32	Relative reflected pulse signal strength
ReturnNumber	uint8	Pulse return number for a given output pulse. A given output laser pulse can have many returns, and they must be marked in order, starting with 1
Roll	float	Roll in degrees
ScanAngleRank	float	Angle degree at which the laser point was output from the system, including the roll of the aircraft. The scan angle is based on being nadir, and -90 the left side of the aircraft in the direction of flight
ScanChannel	uint8	Scan Channel
ScanDirectionFlag	uint8	Direction at which the scanner mirror was traveling at the time of the output pulse. A value of 1 is a positive scan direction, and a bit value of 0 is a negative scan direction, where positive scan direction is a scan moving from the left side of the in-track direction to the right side and negative the opposite
Scattering	double	Scattering of a point; larger values incidate complex (scattered) 3D regions.
ShotNumber	uint64	Shot Number
StartPulse	int32	Relative pulse signal strength
SurfaceVariation	double	Surface variation of a point; larger values indicate higher surface variation.
TextureU	double	U component of a texture location at this point
TextureV	double	V component of a texture location at this point
TextureW	double	W component of a texture location at this point
UserData	uint8	Unspecified user data
Verticality	double	Verticality of a point; larger values indicate vertical structure.
W	double	W coordinate
WanderAngle	double	Wander Angle
X	double	X coordinate
XBodyAccel	double	X Body Acceleration
XBodyAngRate	double	X Body Angle Rate
XVelocity	double	X Velocity
Y	double	Y coordinate
YBodyAccel	double	Y Body Acceleration
YBodyAngRate	double	Y Body Angle Rate
YVelocity	double	Y Velocity
Z	double	Z coordinate
ZBodyAccel	double	Z Body Acceleration
ZBodyAngRate	double	Z Body Angle Rate
ZVelocity	double	Z Velocity