The laslib.net is a library for .net. It can read or write the las/laz file.
C#GPL-3.0
LasLibNet
The LasLibNet is a library coded ONLY by C#, and used to read or write the las/laz file. The author is a teacher and a developer in GIS department of Central Southen University, Hunan province, China. If you any question, you can send email to Ligq168@csu.edu.cn.
// Create a las reader instance
LasReader lasReader = new LasReader();
// Declare a las header variable to get the header of a las file
LasHeader lasHeader;
// Open a las file
if(lasReader.OpenReader(@"d:\sample_data\sample.las"))
{
lasHeader = lasReader.Header;
// Toto about the header or point data.
}
2. How to traverse all point data?
// Create a point reader
lasReader.CreatePointReader();
// Loop through number of points indicated
for (int pointIndex = 0; pointIndex < lasHeader.number_of_point_records; pointIndex++)
{
// Read the point
LasPoint p = lasReader.ReadPoint();
if (p == null)
{
MessageBox.Show(lasReader.Error, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
break;
}
// Todo about the las point.
}
3. How to get different VERSION and FORMAT point data?
If you want know about the las file format, you can access https://en.wikipedia.org/wiki/LAS_file_format.
In the LasLibNet lib, some las point MODEL have been defined. For example:
Model.LasPoint_1_2_Format3 point_1_2_3 = p.ToPoint_1_2_Format3(); // The p is the variable defined in pre step.
Yet, if you want to convert the special version and format point MODEL into LasPoint MODEL. You can:
LasPoint p = new LasPoint();
p.FromPoint_1_2_Format3(point_1_2_3); // The point_1_2_3 is the a variable of the model LasPoint_1_2_Format3.
4. How to create a new las file?
- Create and set the las header setting. For example:
LasHeader header = LasHeader.Instance;
header.Init(); //Set all parameters to the configuration of R1.2 and format3 Las Point.
- Read all point data, and calculat the max and min value for x/y/z, and set these values to header variable.
Get number of points, and set the number_of_point_records. For example:
header.number_of_point_records = points_count;
header.max_x = max_x;
header.min_x = min_x;
header.max_y = max_y;
header.min_y = min_y;
header.max_z = max_z;
header.min_z = min_z;
- Create LasWriter instance, open the writer, and write the header. Codes are following:
LasWriter lasWriter = new LasWriter(newHeader);
if (!lasWriter.OpenWriter(lasFile)) //the lasFile is the las file path wanted to be create.
{
MessageBox.Show(lasWriter.Error, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
lasWriter.CloseWriter();
return;
}
if (!lasWriter.WriteHeader())
{
MessageBox.Show(lasWriter.Error, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
lasWriter.CloseWriter();
return;
}
- Write point data. For example:
foreach (DataRow row in dtCSV.Rows)
{
LasPoint p = new LasPoint();
p.GeoX = double.Parse(row["X"].ToString());
p.GeoY = double.Parse(row["Y"].ToString());
p.GeoZ = double.Parse(row["Z"].ToString());
p.intensity = ushort.Parse(row["I"].ToString());
p.red = ushort.Parse(row["R"].ToString());
p.green = ushort.Parse(row["G"].ToString());
p.blue = ushort.Parse(row["B"].ToString());
}
- Close writer.
lasWriter.CloseWriter();
5. How to read a laz/laszip file?
// Create a las reader instance
IFileReader lazReader = new LazReader();
// Declare a las header variable to get the header of a las file
LasHeader lasHeader;
... ... // Todo like reading the las file.
6. How to convert the laz file into a las file?
bool result = true;
if (this.saveFileDialog.ShowDialog() != DialogResult.OK)
{
MessageBox.Show("You HAVE TO choose a las file!", "Error", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
return;
}
string FileName = this.saveFileDialog.FileName;
IFileWriter lasWriter = null;
if (FileName.ToLower().EndsWith(".las"))
lasWriter = new LasWriter(this.lasHeader);
else if (FileName.ToLower().EndsWith(".laz"))
lasWriter = new LazWriter(this.lasHeader);
else
{
MessageBox.Show("Please choose a file name with LAS or LAZ extend name"
, "Error"
, MessageBoxButtons.OK, MessageBoxIcon.Error);
return;
}
if (!lasWriter.OpenWriter(FileName))
{
MessageBox.Show("Open writer failed : "+lasWriter.Error
, "Error"
, MessageBoxButtons.OK, MessageBoxIcon.Error);
return;
}
result = lasWriter.CreatePointWriter();
if (!result)
{
MessageBox.Show(lasWriter.Error, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
lasWriter.CloseWriter();
return;
}
if (lasWriter.WriteHeader(lasReader.Header) == false)
{
MessageBox.Show(lasWriter.Error, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
lasWriter.CloseWriter();
return;
}
lasReader.SeekPoint(0);
// Loop through number of points indicated
for (int pointIndex = 0; pointIndex < this.lasHeader.number_of_point_records; pointIndex++)
{
// Read the point
LasPoint p = lasReader.ReadPoint();
if (p == null)
{
MessageBox.Show(lasReader.Error, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
break;
}
//Debug.WriteLine(string.Format(" x={0},y={1},z={2}", p.GeoX, p.GeoY, p.GeoZ));
result = lasWriter.WritePoint(p);
if (!result)
{
MessageBox.Show(lasWriter.Error, "Write failed", MessageBoxButtons.OK, MessageBoxIcon.Error);
//Debug.WriteLine(" #Write point failed : " + lasWriter.Error);
break;
}
}
lasWriter.CloseWriter();
