#!/usr/bin/env python
# coding: utf-8

# <table class="ee-notebook-buttons" align="left">
#     <td><a target="_parent"  href="https://github.com/gee-community/geemap/tree/master/tutorials/Image/07_morphological_operations.ipynb"><img width=32px src="https://www.tensorflow.org/images/GitHub-Mark-32px.png" /> View source on GitHub</a></td>
#     <td><a target="_parent"  href="https://nbviewer.jupyter.org/github/gee-community/geemap/blob/master/tutorials/Image/07_morphological_operations.ipynb"><img width=26px src="https://upload.wikimedia.org/wikipedia/commons/thumb/3/38/Jupyter_logo.svg/883px-Jupyter_logo.svg.png" />Notebook Viewer</a></td>
#     <td><a target="_parent"  href="https://colab.research.google.com/github/gee-community/geemap/blob/master/tutorials/Image/07_morphological_operations.ipynb"><img width=26px src="https://www.tensorflow.org/images/colab_logo_32px.png" /> Run in Google Colab</a></td>
# </table>

# # Morphological Operations
# Earth Engine implements morphological operations as focal operations, specifically `focal_max()`, `focal_min()`, `focal_median()`, and `focal_mode()` instance methods in the `Image` class. (These are shortcuts for the more general `reduceNeighborhood()`, which can input the pixels in a kernel to any reducer with a numeric output. See [this page](https://developers.google.com/earth-engine/reducers_reduce_neighborhood) for more information on reducing neighborhoods). The morphological operators are useful for performing operations such as erosion, dilation, opening and closing. For example, to perform an [opening operation](http://en.wikipedia.org/wiki/Opening_(morphology)), use `focal_min()` followed by `focal_max()`:

# ## Install Earth Engine API and geemap
# Install the [Earth Engine Python API](https://developers.google.com/earth-engine/python_install) and [geemap](https://github.com/gee-community/geemap). The **geemap** Python package is built upon the [ipyleaflet](https://github.com/jupyter-widgets/ipyleaflet) and [folium](https://github.com/python-visualization/folium) packages and implements several methods for interacting with Earth Engine data layers, such as `Map.addLayer()`, `Map.setCenter()`, and `Map.centerObject()`.
# The following script checks if the geemap package has been installed. If not, it will install geemap, which automatically installs its [dependencies](https://github.com/gee-community/geemap#dependencies), including earthengine-api, folium, and ipyleaflet.
# 
# **Important note**: A key difference between folium and ipyleaflet is that ipyleaflet is built upon ipywidgets and allows bidirectional communication between the front-end and the backend enabling the use of the map to capture user input, while folium is meant for displaying static data only ([source](https://blog.jupyter.org/interactive-gis-in-jupyter-with-ipyleaflet-52f9657fa7a)). Note that [Google Colab](https://colab.research.google.com/) currently does not support ipyleaflet ([source](https://github.com/googlecolab/colabtools/issues/60#issuecomment-596225619)). Therefore, if you are using geemap with Google Colab, you should use [`import geemap.foliumap`](https://github.com/gee-community/geemap/blob/master/geemap/foliumap.py). If you are using geemap with [binder](https://mybinder.org/) or a local Jupyter notebook server, you can use [`import geemap`](https://github.com/gee-community/geemap/blob/master/geemap/geemap.py), which provides more functionalities for capturing user input (e.g., mouse-clicking and moving).

# In[ ]:


# Installs geemap package
import subprocess

try:
    import geemap
except ImportError:
    print("geemap package not installed. Installing ...")
    subprocess.check_call(["python", "-m", "pip", "install", "geemap"])

# Checks whether this notebook is running on Google Colab
try:
    import google.colab
    import geemap.foliumap as emap
except:
    import geemap as emap

# Authenticates and initializes Earth Engine
import ee

try:
    ee.Initialize()
except Exception as e:
    ee.Authenticate()
    ee.Initialize()


# ## Create an interactive map 
# The default basemap is `Google Satellite`. [Additional basemaps](https://github.com/gee-community/geemap/blob/master/geemap/geemap.py#L13) can be added using the `Map.add_basemap()` function. 

# In[ ]:


Map = geemap.Map(center=[40, -100], zoom=4)
Map.add_basemap("ROADMAP")  # Add Google Map
Map


# ## Add Earth Engine Python script 

# In[ ]:


image = ee.Image("LANDSAT/LC08/C01/T1_TOA/LC08_044034_20140318").select(4).gt(0.2)
Map.setCenter(-122.1899, 37.5010, 13)
Map.addLayer(image, {}, "NIR threshold")

# Define a kernel.
kernel = ee.Kernel.circle(**{"radius": 1})

# Perform an erosion followed by a dilation, display.
opened = image.focal_min(**{"kernel": kernel, "iterations": 2}).focal_max(
    **{"kernel": kernel, "iterations": 2}
)
Map.addLayer(opened, {}, "opened")

Map.addLayerControl()
Map


# Note that in the previous example, a kernel argument is provided to the morphological operator. The pixels covered by non-zero elements of the kernel are used in the computation. The iterations argument indicates how many times to apply the operator.