simple_datashader_bokeh_map.py

from bokeh.models import Range1d
from bokeh.models import WMTSTileSource
from bokeh.models import ImageSource

from bokeh.plotting import figure
from bokeh.plotting import show
from bokeh.plotting import output_file

output_file('datashader_example.html')

tile_options = {}
tile_options['url'] = 'http://tile.stamen.com/toner/{Z}/{X}/{Y}.png'
tile_source = WMTSTileSource(**tile_options)

# create label tile source -----------
tile_label_options = {}
tile_label_options['url'] = 'http://tile.stamen.com/toner-labels/{Z}/{X}/{Y}.png'
tile_label_source = WMTSTileSource(**tile_label_options)

# create datashader image source -----------
shader_url_vars = {}
shader_url_vars['host'] = 'localhost'
shader_url_vars['port'] = 5000
shader_url_vars['layer_name'] = 'CENSUS_SYN_PEOPLE'
shader_url_vars['arl'] = "agg.colorize({'w': 'blue', 'h': 'orange', 'a': 'red', 'o': 'saddlebrown', 'b': 'green'})"

service_url = 'http://{host}:{port}/{layer_name}?'
service_url += 'height={HEIGHT}&'
service_url += 'width={WIDTH}&'
service_url += 'arl={arl}&'
service_url += 'select={XMIN};{YMIN};{XMAX};{YMAX};'

dynamic_image_options = {}
dynamic_image_options['url'] = service_url
dynamic_image_options['extra_url_vars'] = shader_url_vars
dynamic_image_source = ImageSource(**dynamic_image_options)

# create plot -----------
fig = figure(tools='wheel_zoom,pan', title="DATASHADER")
fig.x_range = Range1d(start=-12500000, end=-9000000)
fig.y_range = Range1d(start=4000000, end=5100000)
fig.plot_height = 700
fig.plot_width = 700
fig.min_border = 0
fig.axis.visible = False

fig.add_tile(tile_source)
fig.add_dynamic_image(dynamic_image_source)
fig.add_tile(tile_label_source, **dict(render_parents=False))
show(fig)