Geoviews: Add a slider to choropleth map

问题

I'm working on GeoViews and I'd like to know if we could have a slider as an input for the choropleth map in GeoViews.

I've another variable in gdf, which is year. Is it possible to have a slider to show year wise Total_Crimes?

Edit: Added more information:

gdf dataframe has following variables.

beat_num    Year    Total_Crimes    beat    district    sector  geometry
111 2012    1449    1   01  1   POLYGON ((-87.62451050462798 41.88829675314376...
111 2013    1645    1   01  1   POLYGON ((-87.62451050462798 41.88829675314376...
111 2014    1636    1   01  1   POLYGON ((-87.62451050462798 41.88829675314376...
111 2015    1642    1   01  1   POLYGON ((-87.62451050462798 41.88829675314376...
111 2016    1836    1   01  1   POLYGON ((-87.62451050462798 41.88829675314376...

I've essentially grouped gdf by beat_num and Year and found out Total_Crimes for each group. Datatypes of gdf:

beat_num         int64
Year             int64
Total_Crimes     int64
beat            object
district        object
sector          object
geometry        object

Entire Code:

import geopandas as gpd
import holoviews as hv
import geoviews as gv
import geoviews.tile_sources as gts

hv.extension('bokeh')
geometries = gpd.read_file('geo_export_3b3b25c2-a600-40c3-a663-2f7ad8dc2b9c.shp')
#Reading the shape file for each beat_num.

geometries['beat_num']=geometries['beat_num'].apply(int)
#Converted the beat_num to integers

gdf = gpd.GeoDataFrame(pd.merge(ca_df, geometries))
#dataframe ca_df has total crimes for each beat_num and each year and merged it with geometries to get shape for each beat_num. 

plot_opts = dict(tools=['hover'], width=750, height=700, color_index='Total_Crimes',
                 colorbar=True, toolbar='above', xaxis=None, yaxis=None)
gts.ESRI *gv.Polygons(gdf, vdims=['beat_num', 'Total_Crimes'], label='Chicago Crime Data').opts(plot=plot_opts,style=dict(alpha=0.7))

Output:

回答1:

Yes, it's always possible to have a slider in GeoViews if you want one! I can't quite tell what you're doing from that code snippet, but I'm guessing that gdf is a GeoPandas dataframe, which would presumably have latitude and longitude as key dimensions. To get a slider, you then need to add an additional key dimension ('kdim')for the year. You may also need to aggregate the data by year, if it's not already aggregated in that way. There are examples on pyviz.org and geoviews.org that should get you started, or you can post a more complete example.

来源：https://stackoverflow.com/questions/53272108/geoviews-add-a-slider-to-choropleth-map

标签

python

bokeh

holoviews

geoviews