Htykuut

I have a set of hyperspectral data, a grid of X,Y,Energy where each point is a full spectrum. From those spectra I can create image stacks e.g. image stack 1= sum of counts from channel 600-650 across the grid, image stack 2 = 700-750 etc.

I would like to be able to display the image stacks and when a user clicks on a pixel or adjusts the kdim slider show the full spectrum at that X,Y, Energy point.

At the moment I can show a single image stack and update the spectrum on a click or when changing kdim using the proof of principle code example below.
That's already pretty good but if I increases the number of images (nimages variable in the code) and try and create multiple SingleTap streams I get an error due to the multiple clash on the ['x', 'y'] parameters. I looked at the link_inputs in the "responding to events" section but that operates on a clone and I've tried and failed to set it up across dynamic maps. Could someome provide an example or point me in the right direction on how to do this ?

import holoviews as hv

import numpy as np

hv.extension('bokeh')



def image_extract(energy=0):

    # create a random image as a substitute for looking up the

    # real data 

    return hv.Image(np.random.rand(10,10))



def extract_curve(x=0,y=0,energy=0):

    # create a random curve as a substitute for looking up

    # the real data

    x=np.arange(1000)

    return hv.Curve((x,np.random.rand(1000)),"Counts","channels")



# number of images 

nimages = 1



dmap_list=

pointer_list=

for i in range(nimages):

    img_dmap = hv.DynamicMap(image_extract, kdims=['energy']).redim.range(energy=(0,90))

    pointer = hv.streams.SingleTap(x=0,y=0, source=img_dmap,subscribers=,transient=False)

    pointer_list.append(pointer)

    pointer_dmap = hv.DynamicMap(lambda x,y: hv.Points([(x, y)]), streams=[pointer])

    img =img_dmap*pointer_dmap

    dmap_list.append(img)

dmap_list.append(hv.DynamicMap(extract_curve,kdims=['energy'],streams=pointer_list).redim.range(energy=(0,90)))



layout = hv.Layout(tuple(dmap_list)).cols(2)

layout

It uses hover rather than clicking, but it sounds like you want to do what's in http://datashader.org/topics/landsat.html :

tap = hv.streams.PointerXY(source=true_color)

spectrum_curve = hv.DynamicMap(spectrum, streams=[tap]).redim.range(Luminance=(0, 30000))



tiles * regrid(true_color) + spectrum_curve