Codes for the approval of the MB1 and MB2 Master EAGLE courses at the Julius-Maximilians-Universität Würzburg, Germany.
MB1 course: Map creation
Corresponds to the project for the MB1 course Digital Image Analysis and GIS.
Through the script Project_QGIS_Script.R was intended to work with mosaics at the country level and cut entire regions with memory efficiency. Within this, you can find a higher rating with reference to the previous code for images and mosaics, and a direct way to save plotted graphics for each type of water body. The products of this script. Using the OTB toolbox by QGIS it was used for change detection making an iteration of the different Tiff image created by the R Script. It was possible to made a unique Tiff where was differenced by its Digital Number for each unique year which represent the state of the art of Permanet and Seasonal water to generate a final map that shows the decrease in the body of water of the Aculeo lagoon between 2010 and 2018. It is necessary to add that by means of the histogram visualization of the digital pixel values of the new TIFF created with change detection, the ranges of each year were obtained and classified with different colors for an easier visual representation for the users.
In parallel LandSat 8 satellite images were used with which the Normalized Difference Water Index was calculated using the McFeeters Method, 1996. This is based on the substitution of the SWIR band by the visible green band, highlighting the water masses. In this case, the relation of analysis of multispectral bands will be:
With the above, a Time Series analysis was generated between 2015 and 2019 with a temporal resolution of approximately 15 day to be able to observe the behavior of the body of water using data from another satellite and at the same time obtain the vacuum between 2018 and 2019. It could be observed that after the lagoon dried up it was not observed again that it reappeared.
Because LandSat 8 images cannot show continuity on non-cloudy dates. An analysis of Radar SLC images of the Sentinel 1 satellite was also performed in the last year until the lake disappears. This occurs from April 2017 to April 2018 approximately. The images were processed using the free software SNAP and then a quick analysis was made using Project_Radar_Script.R in R.
It should be noted that all the information acquired through LandSat 8 and Sentinel 1, has small temporary empty spaces, which do not affect the observation of the drought of the Aculeo lagoon.
MB2 course: Project_Script.R
Corresponds to the project for the MB2 course Introduction to Programming and Geostatistics.
Through this script an easy and fast way is proposed to observe the decrease over time of the water level of the Acualeo Lagoon in Chile. It is also possible to modify this code to observe other gaps in the world, using the data provided by Global SDG database and a a preset georeferenced area (which can be changed by a Shapefile).
Link to download the water bodies of Chile by Global SDG database.
One of the most important characteristics of this script is that it is generic, therefore it can be used for any type of body of water in the world while its extent is known. For this, within the code between lines 121 and 153 is the option to download a shapefile that makes up the cadastre of lakes in Chile obtained from the official page of the General direction of waters in Chile. Which can be used to facilitate the understanding of how to use a database such as a shapefile in this script.
Link to download the cadastre of lakes in Chile.
MB1 course:
The script that is called Project_QGIS_Script.R, LandSat8_Script.R, and Project_Radar_Script.R. With these three scripts it was possible to obtain the images and charts that were used for the QGIS project which corresponds to the MB1 course Digital Image Analysis and GIS of the Master EAGLE to create an explicative and visually attractive map.
Within the codes we can find:
- Command to call GDAL in QGIS from RStudio
- Crop the area from a shapefile without using the temporary file from RStudio through GDAL.
- Plot generation and saved directly in a route pre-established by the code.
MB2 course:
The script that concerns us in this project is called Project_Script.R which corresponds to the MB2 course of the Master EAGLE.
Within this code we can find:
- Raster Data of Water Bodies.
- Copy files to other folders.
- Tiff files selected by match of a Shapefile or an object extend made in R in it extent.
- Select of Tiff images in an automatic form and copy to another folder.
- Use Shiny App.
MB1 course:
Created using Project_QGIS_Script.R, OTB toolbox inside of QGIS and LandSat 8 images was possible generated the information need it to elaborate the following map using QGIS.
Here you can see the Change Detection images that were generated by applying the OTB toolbox by QGIS:
Here you can see the charts for LandSat 8 and Sentinel 1 that were generated by applying RStudio scripts for LandSat 8 and SNAP for Sentinel 1.
Here you can see the final Map created to the approval of the MB1 course.
- Click in the following link to download the final file in the complete resolution of the map "Aculeo Lagoon TimeSeries drought map from 2010 - 2018".
MB2 course:
Created using Project_Script.R it is possible to obtain Graphs, Images, GIF and Tables:
- TimeSeries of Permanent Water body for Aculeo Lagoon between 2000 - 2018.
Here you can see some examples of the images that were generated by applying the Project_Script.R for the project of QGIS:
Email: diego.alarcondiaz@gmail.com
LinkedIn: www.linkedin.com/in/diegoalarcóndíaz/
This script was made for testing purposes and can be used and modified in the future by those who deem it convenient.