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  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<a href=\"http://landlab.github.io\"><img style=\"float: left\" src=\"../../landlab_header.png\"></a>"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "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": [
    "from landlab import RasterModelGrid\n",
    "import numpy as np\n",
    "from landlab.plot.imshow import imshow_grid_at_node\n",
    "from matplotlib.pyplot import show\n",
    "%matplotlib inline"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "mg = RasterModelGrid((10, 10))"
   ]
  },
  {
   "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.\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": [
    "imshow_grid_at_node(mg, z)"
   ]
  },
  {
   "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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