Add get_image_collection_video() function

[ErikSeras]

• geemap version: 0.8.5
• Python version: 3.6.9
• Operating System: Google Colab

Description

I would like geemap to have a function to download images made with cartoee.

This is my attempt, in which a video can also be generated using OpenCV.

What I Did

import ee
import geemap
import cv2
import matplotlib.pyplot as plt
import os
from datetime import datetime
from geemap import cartoee

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

def get_image_collection_video(
    ee_ic,
    out_dir,
    vis_params,
    show_region,
    grid_interval,
    plot_title,
    date_format, 
    fig_size,
    dpi_plot,
    format,
    color_north_arrow,
    scale_bar_length,
    scale_bar_color,
    scale_bar_unit,
    video_filename,
    fps,
):
    if not os.path.exists(out_dir):
        os.makedirs(out_dir)

    out_dir = os.path.join(os.getcwd(), out_dir)

    count = int(ee_ic.size().getInfo())
    names = ee_ic.aggregate_array('system:index').getInfo()
    images = ee_ic.toList(count)

    # list of file name
    img_list = []

    for i in range(0, count):
        image = ee.Image(images.get(i))
        name = str(names[i])
        ext = os.path.splitext(name)[0][1:]
        name = name + "." + "png"
        out_img = os.path.join(out_dir, name)
        img_list.append(out_img)

        # Size plot
        plt.figure(figsize = fig_size)

        # Plot image
        ax = cartoee.get_map(image, region=show_region, vis_params = vis_params)

        # Add grid
        cartoee.add_gridlines(ax, interval = grid_interval, linestyle=":")

        # Add title
        ax.set_title(
            label = plot_title + " " + image.date().format(date_format).getInfo() +  " UTC"+ "\n",
            fontsize = 15
        )

        # Add scale bar
        cartoee.add_scale_bar(ax, scale_bar_length, xy=(0.9, 0.02), linewidth=3, color = scale_bar_color, unit = scale_bar_unit, fontsize = 16)
        # Add north arrow
        cartoee.add_north_arrow(ax, 'N', xy=(0.9, 0.18), arrow_length=0.1, text_color= color_north_arrow, arrow_color = color_north_arrow)

        # Save plot
        plt.savefig(fname = out_img, dpi = dpi_plot)

       
        plt.clf()
        plt.close()
    
    
    # Video file name
    output_video_file_name = os.path.join(os.getcwd(), out_dir, video_filename)

    frame = cv2.imread(img_list[0])
    height, width, channels = frame.shape
    frame_size = (width,height)
    fps_video = fps

    # Make mp4
    fourcc = cv2.VideoWriter_fourcc(*'mp4v')

    # Function
    def convert_frames_to_video(
        input_list,
        output_video_file_name,
        fps_video,
        frame_size
    ):   
        out = cv2.VideoWriter(output_video_file_name, fourcc, fps_video, frame_size)
        num_frames = len(input_list)

        for i in range(num_frames):
            img_path = input_list[i]
            img = cv2.imread(img_path)
            out.write(img)
        
        out.release()
        cv2.destroyAllWindows()

    # Use function  
    convert_frames_to_video(
        input_list = img_list,
        output_video_file_name = output_video_file_name,
        fps_video= fps_video,
        frame_size = frame_size
    )

# Example
l8 = ee.ImageCollection("LANDSAT/LC08/C01/T1_SR").filterBounds(point) \
    .filterDate("2015-01-01", "2018-01-01")

visParams = {
  "bands": ['B4', 'B3', 'B2'],
  "min": 0,
  "max": 3000
}

region = [-71,-13.5,-70,-12.5]

get_image_collection_video(
    ee_ic = l8,
    out_dir = "example",
    vis_params = visParams,
    show_region = region,
    grid_interval = (0.2, 0.2),
    plot_title = "Example plot",
    date_format = 'YYYY-MM-dd',
    fig_size = (10.8, 10.8),
    dpi_plot = 100,
    format = "png",
    color_north_arrow = "white",
    scale_bar_length = 10,
    scale_bar_color = "white",
    scale_bar_unit = "km",
    video_filename = "example.mp4",
    fps = 10
)

[giswqs]

@ErikSeras Good work! This function can potentially be added to the cartoee module. The function can be improved with docstrings. Look at this example for documenting functions if you have not done this before. Would you like to submit a pull request so that you can get credits for this and be listed as one of the contributors?

[ErikSeras]

Thanks @giswqs. I have never tried to make a pull request for a Python package. But I'll try.

[giswqs]

Take a look at the pull request instructions here.

For adding docstrings, you can use the VSCode Python Docstring Generator. Docstrings will be automatically extracted when building the API documentation. See https://geemap.org/cartoee/

[giswqs]

@ErikSeras I have improved the function and renamed it as get_image_collection_gif(). In this way, the opencv-python package is optional. Other parameters are optional as well, such as plot title, girdline, north arrow, scale bar, etc. See this notebook example. Thank you for your contribution!