Land Use Change Assessment Two Ways in SAGA GIS

Introduction

The purpose of this tutorial is to introduce users to land use change assessment in SAGA GIS. This will be done two ways, in order to help users to choose which is best for their applications. There will be step-by-step instructions on how to use SAGA GIS to do this assessment.

Land use change assessment

Land use change assessments can be useful to detect the extent of human influence on natural environment. This is often done by taking two satellite images from different time periods and classifying them, and then calculating the difference between both classified images. ADD MORE INFO.

SAGA GIS

SAGA GIS is a free open source software that can be run under Windows and Linux operating systems. SAGA stands for System for Automated Geoscientific Analysis. According to SAGA's website, it is a GIS that has been designed for an easy and effective implementation of spatial algorithms. It offers a comprehensive, growing set of geoscientifc methods and provides easily approachable user interface with many visualisation options. To learn more about SAGA here is the link to their site.

In order to do the analysis outlined on this page, you will need to download SAGA GIS onto your computer, using the following link SAGA GIS download.

Data

The data used in this tutorial was obtained from Google Earth Engine, and I have provided it below. There are two images, the first is an ortho image of Orleans in 2006, and the second is an ortho image of the same area in 2016. These images were chosen as there is a clear change in land use in the 10 years between the images. There are other sources for finding ortho images, such as Land Viewer, and USGS....

File:Orleans2006.tif ... add data.

Pre Classification Workflow

This is adding the data into SAGA, and setting it all up before classifying.

Classifying the data

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Unsupervised classification

After you have opened SAGA GIS, you need to add the two images provided, or your own two images. This can be done using the following steps:

Adding Data into SAGA GIS

In order to add the data into SAGA you must save it onto your computer somewhere where you can find it, then use the following steps. Below, there is also an image depicting the steps.

1. In the top left corner click on Geoprocessing > Imagery > Landsat > Landsat Import with Options

2. Once you've clicked on Landsat Import with Options, a window will pop up like the one below. In this situation you have to click on the ... beside Okay to find the data you would like to select. Once you've selected your data, press Okay.

3. To add both images to the map, in Manager, under Data you must double click on both files, and they will appear