Add lastools.py

lastools.py

@@ -0,0 +1,73 @@
+import os
+import subprocess
+
+
+def call_lastools(tool_name, las_in, las_out=None, args=None):
+    """Send commands to the lastools library.
+
+    Requires lastools in system path.
+
+    Args:
+        tool_name:  name of lastools binary
+        las_in:     bytes from stdout, or path to input point cloud
+        las_out:    '-stdout' to pipe output, or path to output point cloud
+        args:       list of additional arguments, formatted for lastools
+
+    Returns:
+        bytes of output las, if las_out='-stdout'
+        None, if las_out='path/to/las/file'
+
+    Examples:
+
+    # Convert xyz file to las and pipe stdout to a python bytes object
+    las_data = call_lastools('txt2las', las_in='points.xyz', las_out='-stdout',
+                             args=['-parse', 'sxyz'])
+
+    # Clip las_data with a shapefile, and save to a new las file
+    call_lastools('lascrop', las_in=las_data, las_out='points.las',
+                  args=['-poly', 'boundary.shp'])
+    """
+
+    # Start building command string
+    cmd = [tool_name]
+
+    # Parse input
+    if type(las_in) == bytes:
+        # Pipe input las bytes to stdin
+        cmd += ['-stdin']
+        stdin = las_in
+    else:
+        # Load las from file path
+        cmd += ['-i', las_in]
+        stdin = None
+
+    # Parse output
+    if las_out == '-stdout':
+        # Pipe output las to stdout
+        cmd += ['-stdout']
+    elif las_out:
+        # Save output las to file
+        cmd += ['-o', las_out]
+
+    # Append additional lastools arguments, if provided
+    if args:
+        cmd += args
+
+    process = subprocess.Popen(
+        cmd,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        stdin=subprocess.PIPE)
+    stdout, stderr = process.communicate(input=stdin)
+
+    # Handle errors, if detected
+    if process.returncode != 0:
+        print("Error: {} failed on {}".format(tool_name,
+                                              os.path.basename(las_in)))
+        print(stderr.decode())
+
+    # Output piped stdout if required
+    if las_out == '-stdout':
+        return stdout
+    else:
+        return None