notebooks/tutorials/boundary_conds/set_BCs_from_xy.ipynb

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   "source": [
    "# Setting Boundary Conditions: interior rectangle\n",
    "\n",
    "<hr>\n",
    "<small>For more Landlab tutorials, click here: <a href=\"https://landlab.readthedocs.io/en/latest/user_guide/tutorials.html\">https://landlab.readthedocs.io/en/latest/user_guide/tutorials.html</a></small>\n",
    "<hr>\n",
    "\n",
    "This tutorial illustrates how to modify the boundary conditions of an interior rectangle in the grid if you know the x and y coordinates of the rectangle."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "import numpy as np\n",
    "\n",
    "from landlab import RasterModelGrid"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "mg = RasterModelGrid((10, 10))"
   ]
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Known coordinates of rectangle:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "min_x = 2.5\n",
    "max_x = 5.0\n",
    "min_y = 3.5\n",
    "max_y = 7.5"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Define the area inside x and y coordinates:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "x_condition = np.logical_and(mg.x_of_node < max_x, mg.x_of_node > min_x)\n",
    "y_condition = np.logical_and(mg.y_of_node < max_y, mg.y_of_node > min_y)\n",
    "my_nodes = np.logical_and(x_condition, y_condition)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Define boundaries as CLOSED:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "mg.status_at_node[my_nodes] = mg.BC_NODE_IS_CLOSED"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Make a new elevation field for display:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "z = mg.add_zeros(\"topographic__elevation\", at=\"node\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "mg.imshow(z, at=\"node\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Click here for more <a href=\"https://landlab.readthedocs.io/en/latest/user_guide/tutorials.html\">Landlab tutorials</a>"
   ]
  }
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