Landscape Change Assessment using Unsupervised Image Classification in GRASS GIS

Purpose

The purpose of this tutorial is:

Methods

Data Set

Because this tutorial is being written to demonstrate the ability of GRASS GIS to assess changes in landscapes, a data set has been provided for the user. There are many sources that one can find satellite data for different uses, however a data set is being provided to the user so they may follow along with this tutorial with data that has been analysed previously. This data set consists of two GeoTiff files acquired using the Earth Observing System (EOS) Landviewer tool. These GeoTiff files contains an image obtained by Landsat 7 on September 7, 2000 and an image obtained by Landsat 8 on September 23, 2017. Both images contain imagery of the same area of interest (AOI) which consists of a 40.04 km² square area centered at 45.03001°N 75.68135°W. This area is located in Kemptville, Ontario, an area which has undergone development since the early 2000s to accommodate for increased population sizes. The population of Kemptville is expected to rise given it's close proximity to Ottawa, making it an ideal location for commuters to reside, which means that further development is also expected.

Landscape Change Assessment Data Set
Data Information	Data File
GeoTiff file for raster imagery from September 7, 2000 (Landsat 7)	September 2000 File
GeoTiff file for raster imagery from September 23, 2017 (Landsat 8)	September 2017 File

Importing Landsat Rasters

r.in.gdal [(https://grass.osgeo.org/grass78/manuals/r.in.gdal.html]

d.rgb [1]

Map Swipe

Map Swipe tool

Segmentation

i.segment

Pre-Processing

i.cluster

Unsupervised Classification

i.maxlik

Not Covered in this Tutorial

r.smooth.seg - image pre-processing (takes place before segmentation)

References

https://renx.ca/kemptville-building-boom-retail-residential/

Earth Observing System (EOS) Landviewer [2]

GRASS GIS Software [3]