/// <summary>
/// This will only work if point format, point length, offset, and scale are identical.
/// </summary>
public LASHeader(LASHeader[] headers, LASVLR[] vlrs, LASEVLR[] evlrs)
{
var header = headers[0];
var extent = headers.Select(h => h.m_extent).Union3D();
var points = (ulong)headers.Sum(h => (long)h.m_numberOfPointRecords);
var pointsByReturn = new ulong[15];
for (var i = 0; i < pointsByReturn.Length; i++)
{
pointsByReturn[i] = (ulong)headers.Sum(h => (long)h.m_numberOfPointsByReturn[i]);
}
uint legacyPoints = 0;
uint[] legacyPointsByReturn;
if (points > uint.MaxValue)
{
legacyPoints = 0;
legacyPointsByReturn = new uint[5];
}
else
{
legacyPoints = (uint)points;
legacyPointsByReturn = pointsByReturn.Take(5).Select(c => (uint)c).ToArray();
}
m_fileSourceID = header.m_fileSourceID;
m_globalEncoding = header.m_globalEncoding;
m_projectID = header.m_projectID;
m_version = LASVersionInfo.Create(LASVersion.LAS_1_4);
m_systemIdentifier = header.m_systemIdentifier;
m_generatingSoftware = header.m_generatingSoftware;
m_fileCreationDayOfYear = header.m_fileCreationDayOfYear;
m_fileCreationYear = header.m_fileCreationYear;
m_headerSize = c_minHeaderSize[LASVersion.LAS_1_4];
m_offsetToPointData = m_headerSize + (uint)vlrs.Sum(vlr => vlr.Length);
m_numberOfVariableLengthRecords = (uint)vlrs.Length;
m_pointDataRecordFormat = header.m_pointDataRecordFormat;
m_pointDataRecordLength = header.m_pointDataRecordLength;
if (points > uint.MaxValue)
{
m_legacyNumberOfPointRecords = 0;
m_legacyNumberOfPointsByReturn = new uint[5];
}
else
{
m_legacyNumberOfPointRecords = legacyPoints;
m_legacyNumberOfPointsByReturn = legacyPointsByReturn;
}
m_quantization = header.m_quantization;
m_extent = extent;
m_startOfWaveformDataPacketRecord = 0;
m_startOfFirstExtendedVariableLengthRecord = m_offsetToPointData + (points * m_pointDataRecordLength);
m_numberOfExtendedVariableLengthRecords = (uint)evlrs.Length;
m_numberOfPointRecords = points;
m_numberOfPointsByReturn = pointsByReturn;
}
