gis-tools-ts
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A collection of geospatial tools primarily designed for WGS84, Web Mercator, and S2.
323 lines • 14.2 kB
JavaScript
/**
* Reads a point using the Point Data Record Format 0
* @param reader - data reader, works like a DataView
* @param header - las header
* @param offset - where to start reading in the point data
* @param littleEndian - endianess. Defaults to true (LAS always LE but LAZ may have BE)
* @returns - The parsed point with Format 0 metadata
*/
export function getPointFormat0(reader, header, offset = 0, littleEndian = true) {
const { xOffset, yOffset, zOffset, xScaleFactor, yScaleFactor, zScaleFactor } = header;
const bits = reader.getUint32(offset + 14, littleEndian);
const classBits = reader.getUint8(offset + 15);
const point = {
x: reader.getInt32(offset, littleEndian) * xScaleFactor + xOffset,
y: reader.getInt32(offset + 4, littleEndian) * yScaleFactor + yOffset,
z: reader.getInt32(offset + 8, littleEndian) * zScaleFactor + zOffset,
m: {
intensity: reader.getUint16(offset + 12, littleEndian),
returnNumber: bits & 0b00000111, // 3 bits (bits 0 – 2)
numberOfReturns: (bits & 0b00111000) >> 3, // 3 bits (bits 3 – 5)
scanDirectionFlag: (bits & 0b01000000) >> 6, // 1 bit (bit 6)
edgeOfFlightLine: (bits & 0b10000000) >> 7, // 1 bit (bit 7)
classification: toLASClassification(classBits),
isSynthetic: (classBits & (1 << 5)) !== 0,
isKeyPoint: (classBits & (1 << 6)) !== 0,
isWithheld: (classBits & (1 << 7)) !== 0,
scanAngleRank: reader.getInt8(offset + 16),
userData: reader.getUint8(offset + 17),
pointSourceID: reader.getUint16(offset + 18, littleEndian),
},
};
return point;
}
/**
* Reads a point using the Point Data Record Format 1
* @param reader - data reader, works like a DataView
* @param header - las header
* @param offset - where to start reading in the point data
* @param littleEndian - endianess. Defaults to true (LAS always LE but LAZ may have BE)
* @returns - The parsed point with Format 1 metadata
*/
export function getPointFormat1(reader, header, offset = 0, littleEndian = true) {
const point = getPointFormat0(reader, header, offset, littleEndian);
point.m.gpsTime = reader.getFloat64(offset + 20, littleEndian);
return point;
}
/**
* Reads a point using the Point Data Record Format 2
* @param reader - data reader, works like a DataView
* @param header - las header
* @param offset - where to start reading in the point data
* @param littleEndian - endianess. Defaults to true (LAS always LE but LAZ may have BE)
* @returns - The parsed point with Format 2 metadata
*/
export function getPointFormat2(reader, header, offset = 0, littleEndian = true) {
const point = getPointFormat0(reader, header, offset, littleEndian);
point.m.rgba = {
r: reader.getUint16(offset + 20, littleEndian),
g: reader.getUint16(offset + 22, littleEndian),
b: reader.getUint16(offset + 24, littleEndian),
a: 255,
};
return point;
}
/**
* Reads a point using the Point Data Record Format 3
* @param reader - data reader, works like a DataView
* @param header - las header
* @param offset - where to start reading in the point data
* @param littleEndian - endianess. Defaults to true (LAS always LE but LAZ may have BE)
* @returns - The parsed point with Format 3 metadata
*/
export function getPointFormat3(reader, header, offset = 0, littleEndian = true) {
const point = getPointFormat1(reader, header, offset, littleEndian);
point.m.rgba = {
r: reader.getUint16(offset + 28, littleEndian),
g: reader.getUint16(offset + 30, littleEndian),
b: reader.getUint16(offset + 32, littleEndian),
a: 255,
};
return point;
}
/**
* Reads a point using the Point Data Record Format 4
* https://github.com/ASPRSorg/LAS/wiki/Waveform-Data-Packet-Descriptors-Explained
* @param reader - data reader, works like a DataView
* @param header - las header
* @param offset - where to start reading in the point data
* @param littleEndian - endianess. Defaults to true (LAS always LE but LAZ may have BE)
* @returns - The parsed point with Format 4 metadata
*/
export function getPointFormat4(reader, header, offset = 0, littleEndian = true) {
const point = getPointFormat1(reader, header, offset, littleEndian);
point.m.wavePacketDescriptorIndex = reader.getUint8(offset + 28);
point.m.wavePacketOffset = Number(reader.getBigUint64(offset + 29, littleEndian));
point.m.wavePacketLength = reader.getUint32(offset + 37, littleEndian);
point.m.waveformLocationReturnPoint = reader.getFloat32(offset + 41, littleEndian);
point.m.xT = reader.getFloat32(offset + 45, littleEndian);
point.m.yT = reader.getFloat32(offset + 49, littleEndian);
point.m.zT = reader.getFloat32(offset + 53, littleEndian);
return point;
}
/**
* Reads a point using the Point Data Record Format 5
* @param reader - data reader, works like a DataView
* @param header - las header
* @param offset - where to start reading in the point data
* @param littleEndian - endianess. Defaults to true (LAS always LE but LAZ may have BE)
* @returns - The parsed point with Format 4 metadata
*/
export function getPointFormat5(reader, header, offset = 0, littleEndian = true) {
const point = getPointFormat3(reader, header, offset, littleEndian);
point.m.wavePacketDescriptorIndex = reader.getUint8(offset + 34);
point.m.wavePacketOffset = Number(reader.getBigUint64(offset + 35, littleEndian));
point.m.wavePacketLength = reader.getUint32(offset + 43, littleEndian);
point.m.waveformLocationReturnPoint = reader.getFloat32(offset + 47, littleEndian);
point.m.xT = reader.getFloat32(offset + 51, littleEndian);
point.m.yT = reader.getFloat32(offset + 55, littleEndian);
point.m.zT = reader.getFloat32(offset + 59, littleEndian);
return point;
}
/**
* Reads a point using the Point Data Record Format 0
* @param reader - data reader, works like a DataView
* @param header - las header
* @param offset - where to start reading in the point data
* @param littleEndian - endianess. Defaults to true (LAS always LE but LAZ may have BE)
* @returns - The parsed point with Format 0 metadata
*/
export function getPointFormat6(reader, header, offset = 0, littleEndian = true) {
const { xOffset, yOffset, zOffset, xScaleFactor, yScaleFactor, zScaleFactor } = header;
const bits1 = reader.getUint8(offset + 14);
const bits2 = reader.getUint8(offset + 15);
const point = {
x: reader.getInt32(offset, littleEndian) * xScaleFactor + xOffset,
y: reader.getInt32(offset + 4, littleEndian) * yScaleFactor + yOffset,
z: reader.getInt32(offset + 8, littleEndian) * zScaleFactor + zOffset,
m: {
intensity: reader.getUint16(offset + 12, littleEndian),
returnNumber: bits1 & 0b00001111, // 4 bits (bits 0 – 3)
numberOfReturns: (bits1 & 0b11110000) >> 4, // 4 bits (bits 4 – 7)
classificationFlag: toLASClassificationFlag(bits2), // 4 bis (bit 0 - 3)
scannerChannel: (bits2 & 0b00110000) >> 4, // 2 bits (bit 4 - 5)
scanDirectionFlag: (bits2 & 0b01000000) >> 6, // 1 bit (bit 6)
edgeOfFlightLine: (bits2 & 0b10000000) >> 7, // 1 bit (bit 7)
classification: toLASClassification14(reader.getUint8(offset + 16)),
userData: reader.getUint8(offset + 17),
scanAngle: reader.getInt16(offset + 18, littleEndian),
pointSourceID: reader.getUint16(offset + 20, littleEndian),
gpsTime: reader.getFloat64(offset + 22, littleEndian),
},
};
return point;
}
/**
* Reads a point using the Point Data Record Format 7
* @param reader - data reader, works like a DataView
* @param header - las header
* @param offset - where to start reading in the point data
* @param littleEndian - endianess. Defaults to true (LAS always LE but LAZ may have BE)
* @returns - The parsed point with Format 7 metadata
*/
export function getPointFormat7(reader, header, offset = 0, littleEndian = true) {
const point = getPointFormat6(reader, header, offset, littleEndian);
point.m.rgba = {
r: reader.getUint16(offset + 30, littleEndian),
g: reader.getUint16(offset + 32, littleEndian),
b: reader.getUint16(offset + 34, littleEndian),
a: 255,
};
return point;
}
/**
* Reads a point using the Point Data Record Format 8
* @param reader - data reader, works like a DataView
* @param header - las header
* @param offset - where to start reading in the point data
* @param littleEndian - endianess. Defaults to true (LAS always LE but LAZ may have BE)
* @returns - The parsed point with Format 8 metadata
*/
export function getPointFormat8(reader, header, offset = 0, littleEndian = true) {
const point = getPointFormat7(reader, header, offset, littleEndian);
point.m.nir = reader.getUint16(offset + 36, littleEndian);
return point;
}
/**
* Reads a point using the Point Data Record Format 9
* @param reader - data reader, works like a DataView
* @param header - las header
* @param offset - where to start reading in the point data
* @param littleEndian - endianess. Defaults to true (LAS always LE but LAZ may have BE)
* @returns - The parsed point with Format 9 metadata
*/
export function getPointFormat9(reader, header, offset = 0, littleEndian = true) {
const point = getPointFormat6(reader, header, offset, littleEndian);
point.m.wavePacketDescriptorIndex = reader.getInt16(offset + 30, littleEndian);
point.m.wavePacketOffset = Number(reader.getBigUint64(offset + 31, littleEndian));
point.m.wavePacketLength = reader.getUint32(offset + 39, littleEndian);
point.m.waveformLocationReturnPoint = reader.getFloat32(offset + 43, littleEndian);
point.m.xT = reader.getFloat32(offset + 47, littleEndian);
point.m.yT = reader.getFloat32(offset + 51, littleEndian);
point.m.zT = reader.getFloat32(offset + 55, littleEndian);
return point;
}
/**
* Reads a point using the Point Data Record Format 10
* @param reader - data reader, works like a DataView
* @param header - las header
* @param offset - where to start reading in the point data
* @param littleEndian - endianess. Defaults to true (LAS always LE but LAZ may have BE)
* @returns - The parsed point with Format 10 metadata
*/
export function getPointFormat10(reader, header, offset = 0, littleEndian = true) {
const point = getPointFormat7(reader, header, offset, littleEndian);
point.m.wavePacketDescriptorIndex = reader.getUint8(offset + 38);
point.m.wavePacketOffset = Number(reader.getBigUint64(offset + 39, littleEndian));
point.m.wavePacketLength = reader.getUint32(offset + 47, littleEndian);
point.m.waveformLocationReturnPoint = reader.getFloat32(offset + 51, littleEndian);
point.m.xT = reader.getFloat32(offset + 55, littleEndian);
point.m.yT = reader.getFloat32(offset + 59, littleEndian);
point.m.zT = reader.getFloat32(offset + 63, littleEndian);
return point;
}
/**
* Converts a number into a LASClassification
* @param classification - the number
* @returns - the LASClassification
*/
export function toLASClassification(classification) {
// we only wany the first 5 bits
classification &= 0b11111;
if (classification === 0)
return 'Created, Never Classified';
if (classification === 1)
return 'Unclassified';
if (classification === 2)
return 'Ground';
if (classification === 3)
return 'Low Vegetation';
if (classification === 4)
return 'Medium Vegetation';
if (classification === 5)
return 'High Vegetation';
if (classification === 6)
return 'Building';
if (classification === 7)
return 'Low Point (Noise)';
if (classification === 8)
return 'Model Key-point (mass point)';
if (classification === 9)
return 'Water';
if (classification === 12)
return 'Overlap Points';
return 'Reserved';
}
/**
* Converts a number into a classification flag
* @param classFlag - the input
* @returns - the classification flag
*/
export function toLASClassificationFlag(classFlag) {
const firstThreeBits = classFlag & 0b1111;
if (firstThreeBits === 0)
return 'Synthetic';
if (firstThreeBits === 1)
return 'Key-point';
if (firstThreeBits === 2)
return 'Withheld';
if (firstThreeBits === 3)
return 'Overlap';
return 'Unknown';
}
/**
* Converts a number into a LASClassification v1.4
* @param classification - the number
* @returns - the LASClassification
*/
export function toLASClassification14(classification) {
if (classification === 0)
return 'Created, Never Classified';
if (classification === 1)
return 'Unclassified';
if (classification === 2)
return 'Ground';
if (classification === 3)
return 'Low Vegetation';
if (classification === 4)
return 'Medium Vegetation';
if (classification === 5)
return 'High Vegetation';
if (classification === 6)
return 'Building';
if (classification === 7)
return 'Low Point (Noise)';
if (classification === 8)
return 'Reserved';
if (classification === 9)
return 'Water';
if (classification === 10)
return 'Rail';
if (classification === 11)
return 'Road Surface';
if (classification === 12)
return 'Reserved';
if (classification === 13)
return 'Wire – Guard (Shield)';
if (classification === 14)
return 'Wire – Conductor (Phase)';
if (classification === 15)
return 'Transmission Tower';
if (classification === 16)
return 'Wire-structure Connector (e.g. Insulator)';
if (classification === 17)
return 'Bridge Deck';
if (classification === 18)
return 'High Noise';
if (classification >= 19 && classification <= 63)
return 'Reserved';
if (classification >= 64 && classification <= 255)
return 'User Definable';
return 'Missing';
}
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