{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Compute distance to pipeline\n",
    "* Read in a number of locations (geocode if needed)\n",
    "* Compute the distance to the nearest pipeline, in km."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "#Imports\n",
    "import arcpy, os\n",
    "\n",
    "#Set environments\n",
    "arcpy.env.workspace = '..\\\\scratch'\n",
    "arcpy.env.scratchWorkspace = '..\\\\scratch'\n",
    "arcpy.env.overwriteOutput = True"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Data ingestion\n",
    "* Read in the natural gas pipeline dataset (won't work w/o permission)\n",
    "* Read the csv file (with coordinates) into a feature class"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "#Read in the pipeline data\n",
    "gdb_NG = '\\\\\\\\ns-leviathan.win.duke.edu\\\\biogas_GIS\\\\Rextag_Zone2\\\\Rextag_Zone2_Natural_Gas.gdb\\\\Natural_Gas'\n",
    "fc_NaturalGasPipelines =  os.path.join(gdb_NG,'NaturalGasPipelines')\n",
    "if not arcpy.Exists(fc_NaturalGasPipelines):\n",
    "    print(\"Error finding pipeline dataset!\")\n",
    "else:\n",
    "    sr = arcpy.Describe(fc_NaturalGasPipelines).spatialReference\n",
    "    srName = sr.name\n",
    "    srCode = sr.GCSCode\n",
    "    arcpy.env.outputCoordinateSystem=sr\n",
    "    print(\"Natural gas pipeline feature class found.\")\n",
    "    print(\"Spatial reference set to {} (code:{})\".format(srName,srCode))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "#Set path to address data csv file\n",
    "farmFile = '..\\\\data\\\\raw\\\\DairyFarms_18July2019.csv'\n",
    "\n",
    "#Read the data into a feature layer\n",
    "farmPts = arcpy.management.XYTableToPoint(in_table=farmFile,\n",
    "                                          out_feature_class='..\\\\scratch\\\\farmPts',\n",
    "                                          x_field='Longitude',\n",
    "                                          y_field='Latitude',\n",
    "                                          coordinate_system=arcpy.SpatialReference(4269))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Analysis"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "#Compute the distances from each farm feature to the nearest pipeline feature\n",
    "nearTable = '..\\\\scratch\\\\Distances.csv'\n",
    "nearTbl = arcpy.GenerateNearTable_analysis(in_features=farmPts,\n",
    "                                           near_features=fc_NaturalGasPipelines,\n",
    "                                           out_table=nearTable,\n",
    "                                           method='GEODESIC')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "#Read the address file and the near table produced above and join them\n",
    "dfFarms = pd.read_csv(addressFile)\n",
    "dfNear = pd.read_csv(nearTable)\n",
    "dfOut = pd.merge(dfFarms,dfNear,left_index=True,right_index=True)[['Name','NEAR_DIST']]\n",
    "dfOut.columns = ('Name','Distance_m')\n",
    "dfOut['Distance_m'] = dfOut['Distance_m'].round().astype('int')\n",
    "dfOut.to_csv('..\\\\scratch\\\\Distances.csv',index=False)\n",
    "dfOut"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "#Copy farms to new FC\n",
    "farmsPts2 = arcpy.CopyFeatures_management(farmPts,\"..\\\\scratch\\\\farmsPts2.shp\")\n",
    "#Add FID of nearest pipeline\n",
    "arcpy.Near_analysis(in_features=farmsPts2,near_features=fc_NaturalGasPipelines,method='GEODESIC')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "#Join the pipe attributes to the farmsPts2 table\n",
    "arcpy.JoinField_management(in_data=farmsPts2,\n",
    "                           in_field='NEAR_FID',\n",
    "                           join_table=fc_NaturalGasPipelines,\n",
    "                           join_field='OBJECTID',fields=['Name','Operator','Diameter'])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "#Export the table to a csv file\n",
    "arcpy.TableToTable"
   ]
  }
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