added geojson snippet

rueedlinger · rueedlinger · commit 3c91575993e7 · 2016-12-15T23:59:29.000+01:00
diff --git a/geo/geojson.ipynb b/geo/geojson.ipynb
@@ -18,7 +18,26 @@
     "\n",
     "\n",
     "> __Note:__ The data is from the _Open Data Platform Swiss Public Transport_, https://opentransportdata.swiss/en/\n",
-    "\n"
+    "\n",
+    "\n",
+    "### Required libraries\n",
+    "- pandas, http://pandas.pydata.org/\n",
+    "- geojson, https://pypi.python.org/pypi/geojson/\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### Load the data\n",
+    "First let's load the data with pandas. The data frame contains the stations from the public transportations from Switzerland and some from adjoining countries. We have the columns:\n",
+    "- StationID\n",
+    "- Longitude\n",
+    "- Latitude\n",
+    "- Height\n",
+    "- Remark\n",
+    "\n",
+    "Longitude and Latitude should be _WGS 84_ coordinates."
    ]
   },
   {
@@ -103,13 +122,19 @@
     }
    ],
    "source": [
-    "\n",
     "import pandas as pd\n",
     "\n",
     "df = pd.read_csv('data/bfkoordgeo_utf8.csv')\n",
     "df.head()"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Now we do some data cleaning and remove all rows where _Longitude_ and _Latitude_ are _'null'_."
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": 2,
@@ -119,19 +144,24 @@
    },
    "outputs": [],
    "source": [
-    "\n",
     "df = df[df['Longitude'].notnull()]\n",
     "df = df[df['Latitude'].notnull()]\n",
     "\n",
-    "#df[df.isnull().any(axis=1)]\n",
-    "\n",
-    "\n",
-    "import geojson as geojson"
+    "# will display all rows that have null values\n",
+    "#df[df.isnull().any(axis=1)]"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### Convert pandas data frame to GEOJSON\n",
+    "Next we convert the panda data frame to geosjon _FeatureCollection/Feature/Point_. "
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 14,
+   "execution_count": 3,
    "metadata": {
     "collapsed": false
    },
@@ -145,70 +175,50 @@
     }
    ],
    "source": [
-    "\n",
+    "import geojson as geojson\n",
     "\n",
     "values = zip(df['Longitude'], df['Latitude'], df['Remark'])\n",
     "points = [geojson.Feature(geometry=geojson.Point((v[0], v[1])), properties={'name': v[2]}) for v in values]\n",
     "\n",
+    "geo_collection = geojson.FeatureCollection(points)\n",
+    "\n",
     "print(points[0])"
    ]
   },
   {
-   "cell_type": "code",
-   "execution_count": 18,
-   "metadata": {
-    "collapsed": false
-   },
-   "outputs": [],
+   "cell_type": "markdown",
+   "metadata": {},
    "source": [
-    "\n",
-    "\n",
-    "geo_collection = geojson.FeatureCollection(points)\n",
-    "\n"
+    "### Save the geojson (FeatureCollection)  to a file\n",
+    "Finally we dump the geojson to a file."
    ]
   },
   {
    "cell_type": "code",
-   "execution_count": 19,
+   "execution_count": 4,
    "metadata": {
     "collapsed": false
    },
-   "outputs": [],
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "\"\\nwith open('stations.geojson', 'w') as file:\\n    file.write(dump)\\n\""
+      ]
+     },
+     "execution_count": 4,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
    "source": [
     "dump = geojson.dumps(geo_collection, sort_keys=True)\n",
-    "\n"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": 20,
-   "metadata": {
-    "collapsed": false
-   },
-   "outputs": [],
-   "source": [
     "\n",
+    "'''\n",
     "with open('stations.geojson', 'w') as file:\n",
-    "    file.write(dump)\n"
+    "    file.write(dump)\n",
+    "'''"
    ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {
-    "collapsed": false
-   },
-   "outputs": [],
-   "source": []
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {
-    "collapsed": true
-   },
-   "outputs": [],
-   "source": []
   }
  ],
  "metadata": {
