startinpy

A library for modelling and processing 2.5D terrains using a (2D) Delaunay triangulation. The triangulation is computed in 2D, but the z-elevation of the vertices are kept.

The underlying code is written in Rust (so it's rather fast) and robust arithmetic is used (so it shouldn't crash). startinpy uses the startin Rust library and adds several utilities and functions, for instance NumPy support for input/output, exporting to several formats, and easy-of-use.

startinpy allows you to:

insert incrementally points
delete vertices (useful for simplification, interpolation, and other operations)
interpolate with several methods: TIN, natural neighbours, IDW, Laplace, etc.
use other useful terrain Python libraries that are also NumPy-based, eg laspy, rasterio, meshio
output the TIN to several formats: OBJ, PLY, GeoJSON, and CityJSON
store extra attributes with the vertices (the ones from LAS/LAZ)

Documentation

https://startinpy.rtfd.io

Installation

pip

To install the latest release: pip install startinpy

(watch out: this does not work with Linux currently, it installs an old version!)

If you want to compile it yourself

install latest Rust
install maturin
maturin build --release
cd ./target/wheels/
pip install [name-wheel].whl will install it to your local Python

Development

install Rust (v1.39+)
install maturin
maturin develop
move to another folder, and import startinpy shouldn't return any error

Testing

To run the automated test suite:

install the test requirements: pip install -r tests/requirements.txt
pytest

Examples

The folder ./demo contains a few examples.

import startinpy
import numpy as np
import laspy

las = laspy.read("../data/small.laz")
pts = np.vstack((las.x, las.y, las.z)).transpose()

dt = startinpy.DT()
dt.insert(pts)

#-- remove vertex #4
try:
    dt.remove(4)
except Exception as e:
    print(e)

print("# vertices:", dt.number_of_vertices())
print("# triangles:", dt.number_of_triangles())

#-- print the vertices forming the convex hull, in CCW-order
print("CH: ", dt.convex_hull())

#-- fetch all the incident triangles (CCW-ordered) to the vertex #235
vi = 235
one_random_pt = dt.points[vi]
print("one random point:", one_random_pt)
print(dt.incident_triangles_to_vertex(vi))

#-- interpolate at a location with the linear in TIN method
zhat = dt.interpolate({"method": "TIN"}, [[85718.5, 447211.6]])
print("result: ", zhat[0])

hugoledoux/startinpy