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.
• LasLibNet库是用C#编写的、用于读取或写入las/laz文件的.net 库， 作者是中南大学地理信息系的老师，如果你有任何问题，可以发邮件到Ligq168@csu.edu.cn, 或者加QQ41733233.

Usage

1. How to read a las file?

// 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();

Example