{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class=\"contentcontainer med left\" style=\"margin-left: -50px;\">\n",
    "<dl class=\"dl-horizontal\">\n",
    "  <dt>Title</dt> <dd> TriSurface Element</dd>\n",
    "  <dt>Dependencies</dt> <dd>Matplotlib</dd>\n",
    "  <dt>Backends</dt>\n",
    "    <dd><a href='../matplotlib/TriSurface.ipynb'>Matplotlib</a></dd>\n",
    "    <dd><a href='../plotly/TriSurface.ipynb'>Plotly</a></dd>\n",
    "</dl>\n",
    "</div>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "import numpy as np\n",
    "import holoviews as hv\n",
    "hv.extension('matplotlib')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The ``TriSurface`` Element renders any collection of 3D points as a surface by applying [Delaunay triangulation](https://en.wikipedia.org/wiki/Delaunay_triangulation). It is therefore useful for plotting an arbitrary collection of datapoints as a 3D surface. Like other 3D elements it supports ``azimuth``, ``elevation`` and ``distance`` plot options to control the camera position:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "y,x = np.mgrid[-5:5, -5:5] * 0.1\n",
    "heights = np.sin(x**2+y**2)\n",
    "hv.TriSurface((x.flat,y.flat,heights.flat)).opts(\n",
    "    azimuth=30, elevation=30, fig_size=200)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Like all other colormapped plots we can easily add a ``colorbar`` and control the ``cmap`` of the plot:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "u=np.linspace(0,2*np.pi, 24)\n",
    "v=np.linspace(-1,1, 8)\n",
    "u,v=np.meshgrid(u,v)\n",
    "u=u.flatten()\n",
    "v=v.flatten()\n",
    "\n",
    "#evaluate the parameterization at the flattened u and v\n",
    "tp=1+0.5*v*np.cos(u/2.)\n",
    "x=tp*np.cos(u)\n",
    "y=tp*np.sin(u)\n",
    "z=0.5*v*np.sin(u/2.)\n",
    "\n",
    "surface = hv.TriSurface((x, y, z), label='Moebius band')\n",
    "surface.opts(cmap='fire', colorbar=True, fig_size=200)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "For full documentation and the available style and plot options, use ``hv.help(hv.TriSurface).``"
   ]
  }
 ],
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