Visual Basic for Applications/VBA Code to Read ASCII Log Data from LAS File

SummaryEdit

This page lists a VBA Sub procedure to read data from a LAS file. A LAS file is an industry-standard binary format for storing airborne LIDAR data. Sub procedure requirements:

  • A LAS file must be located in the same folder where the macro-enabled Excel file is located
  • The active worksheet must have in cell A1 the name of the LAS file

VBA CodeEdit

Sub ReadProperties()
  Dim numWords As Long
  Dim stringLine As String, fileName As String, lineStringVector() As String, headerStart As String
  Dim n As Long, i As Long, numLineHeader As Long, lenStringVector As Long, j As Long
  Dim colStart As Long, numProp As Long
  Dim rowStart As Long, rowNumCounter As Long, numDepths As Long
  Dim StartDatProp As Range, dataArray(1 To 10000, 1 To 20) As Double

  fileName = Cells(1, 1).Value
  Cells(1, 2).Value = "Num Prop:": Cells(1, 4).Value = "Num Depths"
  
  n = 0: rowStart = 2: colStart = 2: rowNumCounter = 1

  Open fileName For Input As 1
  Do While Not EOF(1)
    Line Input #1, stringLine
    headerStart = Left(stringLine, 2) ' stores in headerStart the first two characters of the string stringLine
    If headerStart = "~A" Then
       numLineHeader = n + 1
       lineStringVector() = Split(Trim(stringLine), " ")
       lenStringVector = UBound(lineStringVector) - LBound(lineStringVector) + 1
       numWords = 0: j = 1
       For i = 0 To lenStringVector - 1
          If lineStringVector(i) <> "" Then
             numWords = numWords + 1
             Cells(rowStart, j).Value = lineStringVector(i)
             j = j + 1
          End If
       Next i
       numProp = numWords - 1
       Cells(1, 3).Value = numProp
    End If
    If numLineHeader > 0 And n >= numLineHeader Then
      lineStringVector() = Split(Trim(stringLine), " ")
      lenStringVector = UBound(lineStringVector) - LBound(lineStringVector) + 1
      j = 0
      For i = 0 To lenStringVector - 1
            If lineStringVector(i) <> "" Then
               Cells(rowStart + rowNumCounter, colStart + j).Value = lineStringVector(i)
               dataArray(rowNumCounter, j + 1) = lineStringVector(i)
               j = j + 1
            End If
      Next i
      rowNumCounter = rowNumCounter + 1
    End If
    n = n + 1
  Loop
  Close 1
  numDepths = rowNumCounter - 1
  Cells(1, 5).Value = numDepths
  Cells(rowStart, 2).Select
  Range(Selection, Selection.End(xlDown)).Select
  Range(Selection, Selection.End(xlToRight)).Select
  Selection.NumberFormat = "0.000"
  Cells(rowStart, 2).Select
End Sub

Example Data to TestEdit

You may create a ASCII file with extension LAS using the following example of data.

Screenshot showing content of LAS file
 
Screenshot showing data in LAS file

Output on worksheet after running VBA SubEdit

Screenshot showing Excel active worksheet after running VBA Sub
 
Shows screenshot of Excel worksheet