Ability to export GOCAD VOXET object files

LoopStructural/export/exporters.py

@@ -2,14 +2,15 @@
 Routines to export geological model data to file in a variety of formats
 """
 import logging
+import os
 from pyevtk.hl import unstructuredGridToVTK, pointsToVTK
 from pyevtk.vtk import VtkTriangle
 import numpy as np
 
 from LoopStructural.utils.helper import create_box
 from LoopStructural.export.file_formats import FileFormat
 
- 
+
 from LoopStructural.utils import getLogger
 logger = getLogger(__name__)
 
@@ -29,7 +30,7 @@ def write_cubeface(model, file_name, data_label, nsteps, file_format):
     nsteps : np.array([num-x-steps, num-y-steps, num-z-steps])
         3d array dimensions
     file_format: export.fileformats.FileFormat object
-        Desired format of exported file
+        Desired format of exported file. Supports VTK
 
     Returns
     -------
@@ -58,7 +59,7 @@ def write_vol(model, file_name, data_label, nsteps, file_format):
     nsteps : np.array([num-x-steps, num-y-steps, num-z-steps])
         3d array dimensions
     file_format: export.fileformats.FileFormat object
-        Desired format of exported file
+        Desired format of exported file. Supports VTK and GOCAD
 
     Returns
     -------
@@ -67,14 +68,16 @@ def write_vol(model, file_name, data_label, nsteps, file_format):
     """
     if file_format == FileFormat.VTK:
         return _write_vol_evtk(model, file_name, data_label, nsteps)
+    if file_format == FileFormat.GOCAD:
+        return _write_vol_gocad(model, file_name, data_label, nsteps)
 
     logger.warning("Cannot export to file - format {} not supported yet".format(str(file_format)))
     return False
 
 
 def _write_cubeface_evtk(model, file_name, data_label, nsteps, real_coords=True):
     """
-    Writes out the model as a cuboid with six rectangular surfaces
+    Writes out the model as a cuboid with six rectangular surfaces in VTK unstructured grid format
 
     Parameters
     ----------
@@ -119,16 +122,17 @@ def _write_cubeface_evtk(model, file_name, data_label, nsteps, real_coords=True)
     ctype = np.full(tri.shape[0], VtkTriangle.tid)
 
     try:
-        unstructuredGridToVTK(file_name, x, y, z, connectivity = conn, offsets = offset, cell_types = ctype, cellData = None, pointData = {data_label: val})
+        unstructuredGridToVTK(file_name, x, y, z, connectivity=conn, offsets=offset, cell_types=ctype,
+                              cellData=None, pointData={data_label: val})
     except Exception as e:
-        logger.warning("Cannot export cuboid surface to file {}: {}".format(file_name, str(e)))
+        logger.warning("Cannot export cuboid surface to VTK file {}: {}".format(file_name, str(e)))
         return False
-    return True 
+    return True
 
 
 def _write_vol_evtk(model, file_name, data_label, nsteps, real_coords=True):
     """
-    Writes out the model as a 3d volume grid
+    Writes out the model as a 3d volume grid in VTK points format
 
     Parameters
     ----------
@@ -153,12 +157,13 @@ def _write_vol_evtk(model, file_name, data_label, nsteps, real_coords=True):
 
     # Generate model values in 3d grid
     xx, yy, zz = np.meshgrid(loop_X, loop_Y, loop_Z, indexing='ij')
+    # xyz is N x 3 vector array
     xyz = np.array([xx.flatten(), yy.flatten(), zz.flatten()]).T
     vals = model.evaluate_model(xyz, scale=False)
     if real_coords:
         model.rescale(xyz)
 
-    # Define vertices
+    # Define vertices - xyz.shape[0] is length of vector array
     x = np.zeros(xyz.shape[0])
     y = np.zeros(xyz.shape[0])
     z = np.zeros(xyz.shape[0])
@@ -167,10 +172,122 @@ def _write_vol_evtk(model, file_name, data_label, nsteps, real_coords=True):
 
     # Write to grid
     try:
-        pointsToVTK(file_name, x, y, z, data= { data_label: vals})
+        pointsToVTK(file_name, x, y, z, data={data_label: vals})
     except Exception as e:
-        logger.warning("Cannot export volume to file {}: {}".format(file_name, str(e)))
+        logger.warning("Cannot export volume to VTK file {}: {}".format(file_name, str(e)))
         return False
-    return True 
+    return True
+
 
+def _write_vol_gocad(model, file_name, data_label, nsteps, real_coords=True):
+    """
+    Writes out the model as a 3d volume grid in GOCAD VOXET object format
+
+    Parameters
+    ----------
+    model : GeologicalModel object
+        Geological model to export
+    file_name : string
+        Name of file that model is exported to, including path, but without the file extension
+    data_label : string
+        A data label to insert into export file
+    nsteps : np.array([num-x-steps, num-y-steps, num-z-steps])
+        3d array dimensions
 
+    Returns
+    -------
+    True if successful
+
+    """
+    # Define grid spacing in model scale coords
+    loop_X = np.linspace(model.bounding_box[0, 0], model.bounding_box[1, 0], nsteps[0])
+    loop_Y = np.linspace(model.bounding_box[0, 1], model.bounding_box[1, 1], nsteps[1])
+    loop_Z = np.linspace(model.bounding_box[0, 2], model.bounding_box[1, 2], nsteps[2])
+
+    # Generate model values in 3d grid
+    xx, yy, zz = np.meshgrid(loop_X, loop_Y, loop_Z, indexing='ij')
+    # xyz is N x 3 vector array
+    xyz = np.array([xx.flatten(), yy.flatten(), zz.flatten()]).T
+    vals = model.evaluate_model(xyz, scale=False)
+    # Use FORTRAN style indexing for GOCAD VOXET
+    vol_vals = np.reshape(vals, nsteps, order='F')
+    bbox = model.bounding_box[:]
+
+    # Convert bounding box to real world scale coords
+    if real_coords:
+        model.rescale(bbox)
+
+    # If integer values
+    if type(vals[0]) is np.int64:
+        d_type = np.int8
+        no_data_val = None
+        prop_esize = 1
+        prop_storage_type = "Octet"
+
+    # If float values
+    elif type(vals[0]) is np.float32:
+        d_type = np.dtype('>f4')
+        no_data_val = -999999.0
+        prop_esize = 4
+        prop_storage_type = "Float"
+    else:
+        logger.warning("Cannot export volume to GOCAD VOXET file: Unsupported type {}".format(type(vals[0])))
+        return False
+
+    # Write out VOXET file
+    vo_filename = file_name + ".vo"
+    data_filename = file_name + "@@"
+    try:
+        with open(vo_filename, "w") as fp:
+            fp.write("""GOCAD Voxet 1
+HEADER {{
+name: {name}
+}}
+GOCAD_ORIGINAL_COORDINATE_SYSTEM
+NAME Default
+AXIS_NAME "X" "Y" "Z"
+AXIS_UNIT "m" "m" "m"
+ZPOSITIVE Elevation
+END_ORIGINAL_COORDINATE_SYSTEM
+AXIS_O 0.000000 0.000000 0.000000
+AXIS_U 1.000000 0.000000 0.000000
+AXIS_V 0.000000 1.000000 0.000000
+AXIS_W 0.000000 0.000000 1.000000
+AXIS_MIN {axismin1} {axismin2} {axismin3}
+AXIS_MAX {axismax1} {axismax2} {axismax3}
+AXIS_N {nsteps1} {nsteps2} {nsteps3}
+AXIS_NAME "X" "Y" "Z"
+AXIS_UNIT "m" "m" "m"
+AXIS_TYPE even even even
+PROPERTY 1 {propname}
+PROPERTY_CLASS 1 {propname}
+PROP_UNIT 1 {propname}
+PROPERTY_CLASS_HEADER 1 {propname} {{
+}}
+PROPERTY_SUBCLASS 1 QUANTITY {prop_storage_type}
+""".format(name=os.path.basename(file_name),
+                nsteps1=nsteps[0], nsteps2=nsteps[1], nsteps3=nsteps[2],
+                axismin1=bbox[0, 0], axismin2=bbox[0, 1], axismin3=bbox[0, 2],
+                axismax1=bbox[1, 0], axismax2=bbox[1, 1], axismax3=bbox[1, 2],
+                propname=data_label, prop_storage_type=prop_storage_type))
+            if no_data_val is not None:
+                fp.write("PROP_NO_DATA_VALUE 1 {no_data_val}\n".format(no_data_val=no_data_val))
+            fp.write("""PROP_ETYPE 1 IEEE
+PROP_FORMAT 1 RAW
+PROP_ESIZE 1 {prop_esize}
+PROP_OFFSET 1 0
+PROP_FILE 1 {prop_file}
+END\n""".format(prop_file=data_filename, prop_esize=prop_esize))
+    except IOError as exc:
+        logger.warning("Cannot export volume to GOCAD VOXET file {}: {}".format(vo_filename, str(exc)))
+        return False
+
+    # Write out accompanying binary data file
+    export_vals = np.array(vol_vals, dtype=d_type)
+    try:
+        with open(data_filename, "wb") as fp:
+            export_vals.tofile(fp)
+    except IOError as exc:
+        logger.warning("Cannot export volume to GOCAD VOXET data file {}: {}".format(data_filename, str(exc)))
+        return False
+    return True

LoopStructural/export/file_formats.py

@@ -3,10 +3,11 @@
 """
 from enum import Enum
 
+
 class FileFormat(Enum):
-    """ Enumeration of file export formats 
+    """ Enumeration of file export formats
     """
-    OBJ = 1
+    OBJ = 1  # Not supported yet
     VTK = 2
-    GZ = 3 # Not supported yet
-    GLTF = 4 # Not supported yet
+    GOCAD = 3
+    GLTF = 4  # Not supported yet