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ArcGIS API for Python

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Building a change detection app using Jupyter Dashboard

The Python API, along with the Jupyter Dashboard project enables Python developers to quickly build and prototype interactive web apps. This sample illustrates one such app which can be used to detect the changes in vegetation between the two dates. Increases in vegetation are shown in green, and decreases are shown in magenta.

This sample uses the fast on-the-fly processing power of raster functions available in the raster module of the Python API.

To run this sample you need `jupyter_dashboards` package in your conda environment. You can install it as shown below. For information on this, [refer to the install instructions](http://jupyter-dashboards-layout.readthedocs.io/en/latest/getting-started.html#installing-and-enabling)
conda install jupyter_dashboards -c conda-forge

Connect to ArcGIS Online

In [ ]:
!conda install jupyter_dashboards -c conda-forge -y
In [1]:
from arcgis.gis import GIS
from arcgis.geocoding import geocode
from arcgis.raster.functions import *
from arcgis import geometry
    
import pandas as pd

# connect as an anonymous user
gis = GIS()

# search for the landsat multispectral imagery layer
landsat_item = gis.content.search("Landsat Multispectral tags:'Landsat on AWS','landsat 8', 'Multispectral', 'Multitemporal', 'imagery', 'temporal', 'MS'", 'Imagery Layer', outside_org=True)[0]
landsat = landsat_item.layers[0]
df = None

Create widget controls to accept place of interest

We use the widgets module from ipywidgets to create a text box and command button controls. These controls allow the user to specify a place of interest.

In [2]:
import ipywidgets as widgets

# text box widget
location = widgets.Text(value='Ranchi, India', placeholder='Ranchi, India',
                        description='Location:', disabled=False)

# command button widget
gobtn = widgets.Button(description='Go', disabled=False,
                       button_style='', tooltip='Go', icon='check')

# define what happens whent the command button is clicked
def on_gobutton_clicked(b):
    global df
    global m
    global oldslider
    
    # geocode the place name and set that as the map's extent
    area = geocode(location.value)[0]
    m.extent = area['extent']
    df = filter_images()
    
gobtn.on_click(on_gobutton_clicked)

location_items = [location, gobtn]
widgets.HBox(location_items)

Create the map widget and load the landsat imagery layer

In [1]:
m = gis.map(location.value)
m.add_layer(landsat)
display(m)
Out[1]: