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