OMF API Example

This (very impractical) example shows usage of the OMF API.

Also, this example builds elements all at once. They can also be initialized with no arguments, and properties can be set one-by-one (see code snippet at bottom of page).

import datetime
import numpy as np
import os
import png
import omf

# setup sample files
dir = os.getcwd()
png_file = os.path.join(dir, "example.png")
omf_file = os.path.join(dir, "example.omf")
for f in (png_file, omf_file):
    if os.path.exists(f):
        os.remove(f)
img = ["110010010011", "101011010100", "110010110101", "100010010011"]
img = [[int(val) for val in value] for value in img]
writer = png.Writer(len(img[0]), len(img), greyscale=True, bitdepth=16)
with open(png_file, "wb") as file:
    writer.write(file, img)

proj = omf.Project(
    name="Test project",
    description="Just some assorted elements",
)
pts = omf.PointSet(
    name="Random Points",
    description="Just random points",
    vertices=np.random.rand(100, 3),
    attributes=[
        omf.NumericAttribute(
            name="rand attr",
            array=np.random.rand(100),
            location="vertices",
        ),
        omf.NumericAttribute(
            name="More rand attr",
            array=np.random.rand(100),
            location="vertices",
        ),
    ],
    textures=[
        omf.ProjectedTexture(
            name="test image",
            image=png_file,
            origin=[0, 0, 0],
            axis_u=[1, 0, 0],
            axis_v=[0, 1, 0],
        ),
        omf.ProjectedTexture(
            name="test image",
            image=png_file,
            origin=[0, 0, 0],
            axis_u=[1, 0, 0],
            axis_v=[0, 0, 1],
        ),
    ],
    metadata={
        "color": "green",
    },
)
lin = omf.LineSet(
    name="Random Line",
    vertices=np.random.rand(100, 3),
    segments=np.floor(np.random.rand(50, 2) * 100).astype(int),
    attributes=[
        omf.NumericAttribute(
            name="rand vert attr",
            array=np.random.rand(100),
            location="vertices",
        ),
        omf.NumericAttribute(
            name="rand segment attr",
            array=np.random.rand(50),
            location="segments",
        ),
    ],
    metadata={
        "color": "#0000FF",
    },
)
surf = omf.Surface(
    name="trisurf",
    vertices=np.random.rand(100, 3),
    triangles=np.floor(np.random.rand(50, 3) * 100).astype(int),
    attributes=[
        omf.NumericAttribute(
            name="rand vert attr",
            array=np.random.rand(100),
            location="vertices",
        ),
        omf.NumericAttribute(
            name="rand face attr",
            array=np.random.rand(50),
            location="faces",
        ),
    ],
    metadata={
        "color": [100, 200, 200],
    },
)
grid = omf.TensorGridSurface(
    name="gridsurf",
    tensor_u=np.ones(10).astype(float),
    tensor_v=np.ones(15).astype(float),
    origin=[50.0, 50.0, 50.0],
    axis_u=[1.0, 0, 0],
    axis_v=[0, 0, 1.0],
    offset_w=np.random.rand(11 * 16),
    attributes=[
        omf.NumericAttribute(
            name="rand vert attr",
            array=np.random.rand(11 * 16),
            location="vertices",
        ),
        omf.NumericAttribute(
            name="rand face attr",
            array=np.random.rand(10 * 15),
            location="faces",
        ),
    ],
    textures=[
        omf.ProjectedTexture(
            name="test image",
            image=png_file,
            origin=[2.0, 2.0, 2.0],
            axis_u=[5.0, 0, 0],
            axis_v=[0, 2.0, 5.0],
        ),
    ],
)
vol = omf.TensorGridBlockModel(
    name="vol",
    tensor_u=np.ones(10).astype(float),
    tensor_v=np.ones(15).astype(float),
    tensor_w=np.ones(20).astype(float),
    origin=[10.0, 10.0, -10],
    attributes=[
        omf.NumericAttribute(
            name="random attr", location="cells", array=np.random.rand(10 * 15 * 20)
        ),
    ],
)

proj.elements = [pts, lin, surf, grid, vol]

proj.metadata = {
    "coordinate_reference_system": "epsg 3857",
    "date_created": datetime.datetime.utcnow(),
    "version": "v1.3",
    "revision": "10",
}

assert proj.validate()

omf.save(proj, omf_file)

Piecewise building example:

...
pts = omf.PointSet()
pts.name = 'Random Points',
pts.vertices = np.random.rand(100, 3)
...