散景滑块在Django上的更新

问题描述

我可以在Django上使用bokeh在Choropleth地图上显示GeoJson数据，但无法基于滑块输入来更新源数据框。使用CustomJS回调，似乎可以从JS内修改简单数据框，但是我们如何查询从Django模型获得的数据框？

下面是我的代码，任何帮助将不胜感激。

#this is the view
def dataviz(request):
#load the shapefile for world map
gdf = geopandas.read_file('/home/naveed/ne_50m_admin_0_countries/ne_50m_admin_0_countries.shp')[['ADMIN','ADM0_A3','geometry']]

#Rename columns.
gdf.columns = ['country','country_code','geometry']

    #function to return geojson data based on date
    def geojson_data(day):
        if day == 10: day = datetime.date(2020,8,10)

        df = pandas.DataFrame.from_records(OxCases.objects.filter(count_date=day).values_list())
        df = df[[1,4]]
        df.columns = ['confirmed_cases','country_code']
        merged_df = gdf.merge(df,left_on='country_code',right_on='country_code')    
        geojson_data = json.dumps(json.loads(merged_df.to_json()))
        return geojson_data

    p = figure(title='My geo map',plot_width=1150,plot_height=500,tools="wheel_zoom,pan",background_fill_color='#FFFFFF')
    p.toolbar.active_scroll = p.select_one(WheelZoomTool)
    p.toolbar_location = None
    p.xgrid.visible = False
    p.ygrid.visible = False


    hover = HoverTool(tooltips = [('','@country_code'),('','@confirmed_cases')],# callback = CustomJS(code = code_hover)
        )
    p.add_tools(hover)
    palette = d3['Category20c'][12]
    # palette = brewer['BuGn'][9]
    #Reverse color order so that dark blue is highest obesity.
    palette = palette[::-1]
    #Instantiate LinearColorMapper that linearly maps numbers in a range,into a sequence of colors.
    color_mapper = LinearColorMapper(palette = palette)

    color_bar = ColorBar(color_mapper=color_mapper,label_standoff=10,width = 20,formatter=NumeralTickFormatter(format='0.0a'),border_line_color=None,location = (0,0),orientation = 'vertical')

    day = date(2020,7,1)

    source = GeoJSONDataSource(geojson = geojson_data(day))

    p.patches('xs','ys',source = source,fill_color = {'field' :'confirmed_cases','transform' : color_mapper},line_color = '#585858',line_width = 0.25,fill_alpha = 0.8
        )
    p.add_layout(color_bar,'right')
    
    #PROBLEM IS HERE
    handler = CustomJS(args={'source':source},code="""
       //need to change the 'day' value to query the dataframe in geojson_data function
       source.geojson = geojson_data(10) //doesnt work obvIoUsly
       //console.log('source data is ',source)
       source.change.emit();
    """)

    slider = Slider(title = 'Date',start = 1,end = 30,step = 1,value = 5)
    slider.js_on_change('value',handler)

    layout = column(p,slider)

    map_data = json.dumps(json_item(layout))

    return render(request,'base.html',{'map_data': map_data})

解决方法

暂无找到可以解决该程序问题的有效方法，小编努力寻找整理中！

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bokeh django django