Develop Reference

Folium not recognizing JSON from TravelTime

I'm attempting to create a isochrone map in Jupyter Notebook/Folium, showing how far from downtown Chicago you could get in 45 minutes by car. TravelTime (TravelTime.com) has a ton of excellent APIs to do this, but I'm unable to plot them into Folium/Jupyter Notebook.
Here's a link to the JSON produced by TravelTime.
Here's what I've tried codewise:
import folium
import json
m = folium.Map([41.87899134154521, -87.63554279241286], zoom_start=6.5)
with open('chicago.json', 'r') as openfile:
json_object = json.load(openfile)
folium.GeoJson(json_object).add_to(m)
m
It produces a blank Folium map. No polygon showing the drivetime json. Console has an error message:
"Uncaught Error: Invalid GeoJSON object."
The output produced by TravelTime does seem much different than other GeoJSONs I've seen on Stackoverflow and elsewhere.
I tried converting the JSON to a dict, but that didn't work.

Anybody having the same problem as me, see this post by a Travel Time dev to get Travel Time to directly generate a GeoJson for you.

can't open shape file with GeoPandas

I don't seem to be able to open the zip3.zip shape file I download from (http://www.vdstech.com/usa-data.aspx)
Here is my code:
import geopandas as gpd
data = gpd.read_file("data/zip3.shp")
this gives me the error:
CPLE_AppDefinedError: b'Recode from CP437 to UTF-8 failed with the error: "Invalid argument".'

As per my answer on this question, seems like your dataset contains non-UTF characters. If you are facing this similar issue, chances are that using encoding-"utf-8" won't help as Fiona's open() call will still fail.
If other solutions don't work, two solutions I propose that solved this issue are:
Open your shapefile on a GIS editor (like QGis), then save it again making sure you select the Encoding option to "UTF-8". After this you should have no problem when calling gpd.read_file("data/zip3.shp").
You can also achieve this format change in Python using GDAL, by reading your shapefile and saving it again. This will effectively change the encoding to UTF-8, as this is the default encoding as indicated in the docs for the CreateDataSource() method. For this try the following code snippet:
from osgeo import ogr
driver = ogr.GetDriverByName("ESRI Shapefile")
ds = driver.Open("nbac_2016_r2_20170707_1114.shp", 0) #open your shapefile
#get its layer
layer = ds.GetLayer()
#create new shapefile to convert
ds2 = driver.CreateDataSource('convertedShape.shp')
#create a Polygon layer, as the one your Shapefile has
layer2 = ds2.CreateLayer('', None, ogr.wkbPolygon)
#iterate over all features of your original shapefile
for feature in layer:
#and create a new feature on your converted shapefile with those features
layer2.CreateFeature(feature)
#proper closing
ds = layer = ds2 = layer2 = None

It looks like this shapefile doesn't have an associated cpg specifying the encoding of the .dbf file, and then falling back to trying to use your default system encoding isn't working either. You should be able to open this with:
data = gpd.read_file("data/zip3.shp", encoding="utf-8")
geopandas relies on fiona for shapefile reading, and you may need to upgrade your fiona version for this to work; see some discussion here

Since you probably have GDAL installed, I recommend converting the file to UTF-8 using the CLI:
ogr2ogr output.shp input.shp -lco ENCODING=UTF-8
Worked like a charm for me. It's much faster than QGIS and can be used in a cluster environment. I also posted this answer here. Specifying the encoding in geopandas did not work for me.

Maybe the file is dependent on other files.
I faced the same problem and when I copied other files that this shapefile is dependent on, the code ran correctly but requested to install another package called descartes. When I installed the package, the code ran correctly

Choropleth map with OpenStreetMap data

My goal is to get a so-called "choropleth map" (I guess) of the zip code areas in Germany. I have found the python package "folium" but it seems like it takes a .json file as input:
https://github.com/python-visualization/folium
On OpenStreetMap I only see shp.zip and .osm.pbf files. Inside the shp.zip archive I find all sorts of file endings which I have never heard of but no .json file. How do I use the data from OpenStreetMap to feed folium? Am I running into the wrong direction?

If you want to create a choropleth map you must follow these steps:
First you need a file containing info about the regions of that country. A sample .json file has been supplied with this answer, however, there are actually many file formats commonly used for maps. In your case, you need to convert your OSM shape file (.shp) into a more modern file type like .geojson. Thankfully we have ogr2ogr to do this last part:
ogr2ogr -f GeoJSON -t_srs EPSG:4326 -simplify 1000 [name].geojson [name].shp
Advice: You can also extract the administrative borders from these web sites:
* [OSM Boundaries Map 4.2][2]
* [Mapzen][3]
* [Geofabrik][4]
Download data based on it (a .csv file, for example). Obviously, the file must have a column with the ZIP Codes of that country.
Once you get these files the rest is straightforward, Follium will create the choropleth map automatically.
I wrote a simple example of this about the unemployment rate in the US:
Code:
import folium
import pandas as pd
osm = folium.Map([43, -100], zoom_start=4)
osm.choropleth(
geo_str = open('US_states.json').read(),
data = pd.read_csv("US_unemployment.csv"),
columns = ['State', 'Unemployment'],
key_on = 'feature.id',
fill_color = 'YlGn',
)
Output:

I haven't done this myself but there are various solutions for converting OSM files (.osm or .pbf) to (geo)json. For example osmtogeojson. More tools can be found at the GeoJSON page in the OSM wiki.

I went to https://overpass-turbo.eu/ (which retrieves data from openstreetmap via a specific Query Language QL) and hit run on the following code:
[timeout:900];
area[name="Deutschland"][admin_level=2][boundary=administrative]->.myarea;
rel(area.myarea)["boundary"="postal_code"];
out geom;
You can "export to geojson" but in my case that didn't work because it's too much data which cannot be processed inside the browser. But exporting the "raw data" works. So I did that and then I used "osmtogeojson" to get the right format. After that I was able to feed my openstreetmap data to folium as described in the tutorial of folium.
This answer was posted as an edit to the question Choropleth map with OpenStreetMap data by the OP user3182532 under CC BY-SA 3.0.

GeoJSON data not displaying in Python folium map

I am trying to display the following geojson file in a folium map in Python but it just shows an empty map with none of the data.
Here are the steps I have tried:
I tried using the python code below but nothing shows up.
I tried other geojson files in the github repository below using the same code and the data show up without any issue, so it looks like my python code is fine
I opened the "census_tracts_2010.geojson" file in github and Mapshaper, the data showed up perfectly without any issue, so it doesn't look like the geojson file is corrupted
Could anyone please let me know how I can fix it?
Geojson file:
https://github.com/dwillis/nyc-maps/blob/master/census_tracts_2010.geojson
Python code:
import folium
m = folium.Map(location=[40.66393072,-73.93827499], zoom_start=13)
m.choropleth(geo_path="census_tracts_2010.geojson")
m.save(outfile='datamap.html')
Thanks a lot!

That file is not a GeoJson it is a TopoJson. You need to use folium.TopoJson instead.
import folium
m = folium.Map(location=[40.66393072,-73.93827499], zoom_start=13)
folium.TopoJson(
open('census_tracts_2010.geojson'),
object_path='objects.nyct2010',
).add_to(m)
m

You need to open the geojson file.
m.choropleth(open("census_tracts_2010.geojson"))
Take a look at the examples https://folium.readthedocs.io/en/latest/quickstart.html

Try this: m.add_child(folium.GeoJson(data = open("census_tracts_2010.geojson"))) and then call m.save() fun

python vincent needing url address

I'm using vincent a data visualization package. One of the inputs it takes is path to data.
(from the documentation)
`geo_data` needs to be passed as a list of dicts with the following
| format:
| {
| name: data name
| url: path_to_data,
| feature: TopoJSON object set (ex: 'countries')
| }
|
I have a topo.json file on my computer, but when I run that in, ipython says loading failed.
map=r'C:\Users\chungkim271\Desktop\DC housing\dc.json'
geo_data = [{'name': 'DC',
'url': map,
'feature': "collection"}]
vis = vincent.Map(geo_data=geo_data, scale=1000)
vis
Do you know if vincent only takes url addresses, and if so, what is the quickest way i can get an url address for this file?
Thanks in advance

It seems that you're using it in Jupyter Notebook. If no, my reply is irrelevant for your case.
AFAIK, vincent needs this topojson file to be available through web server (so javascript from your browser will be able to download it to build the map). If the topojson file is somewhere in the Jupyter root dir then it's available (and you can provide relative path to it), otherwise it's not.
To determine relative path you can use something like this:
import os
relpath = os.path.relpath('abs-path-to-geodata', os.path.abspath(os.path.curdir))

I know that this post is old, hopefully this helps someone. I am not sure what map you are looking for, but here is the URL for the world map
world_topo="https://raw.githubusercontent.com/wrobstory/vincent_map_data/master/world-countries.topo.json"
and the USA state maps
state_topo = "https://raw.githubusercontent.com/wrobstory/vincent_map_data/master/us_states.topo.json"
I got this working beautifully, hope this is helpful for someone!