ASTER app

This is a web application built with streamlit and geemap. geemap is python package for interactive geospatial analysis and visualization with Google Earth Engine. The application can be accessed through the link https://aster-app.streamlit.app/. The image processing is carried out using the free tier of my google cloud service account.

Brief about the application

The application uses ASTER_LIT data hosted in google earth engine which is available through this link. The preprocessing steps were done using the code in the github repo ASTER_preprocessing with minor changes to the water masking functions. See the repo for all the image pre processing workflow. Image trimming functions were included to prevent lines appearing in the final output image. The preprocessing functions uses the image reducer functions of earth engine to provide a cloud free image. If there are clouds, if any, present in the processed image, cloud masking function will mask the clouds.

Steps for generating the mineral indices map

1. Enter the bounding cordinates of the area in Decimal Degrees and press submit Maximum area that the app can process is limited to 800 sq.km due to free google cloud quota limits set by earth engine.
2. Lines may appear in the final output image due to errors in the ASTER scene edges. Enter trimming distance (50 or greater) for preventing this. Press submit.
3. Enter values to mask vegetation and press submit. If you do not want to mask vegetation, enter 1, otherwise try values between 0.5 and 1.
4. Enter the image resolution to be downloaded (any value between 30 to 90) or accept the default value of 30.
5. Finally select the mineral indices from the drop down and wait for the image to appear. The images will appear white since the app uses the default min and max values for visualisation of the final output image. Since min and max values will be different for the different indices selected, download the image and view in any GIS software. If any "User memory limit exceeded" error appears, clear the values from drop down box, press clear cache button, decrease the resolution in the previous step and try again.
6. If any other error occurs in the final step, simply refresh the page.

Demo

Run Locally

Clone the project

  git clone https://github.com/soorajgeo/ASTER_app.git

Go to the project directory

  cd project_directory

Create virtual environment and install dependencies in a virtual environment

  pip install -r requirements.txt

run the python file

  streamlit run app.py