Lab 8

Introduction

Lab 8's goal was to teach us how to classify different surfaces so that they can be automatically defined with the program. For this, we used a tutorial on the learn ArcGIS website. the purpose of defining different surfaces is to show where different things are using brighter, more contrasting colors. 

Process

This tutorial started off with giving us the premade images that we used for the reclassification. 

The image provided for this project is a raster dataset which allows it to be easily manipulated in ArcGIS. The first part of the manipulation is to use the raster function that extracts the bands of the different surfaces of the image. Next, we want to group up the pixels of each differing band to make them easier to classify. for this, we use the classification wizard. This takes similar bands and softens the edges to make them more visible. Then we start to classify similar bands into manmade and natural which we call impervious and pervious. This would be the roads, driveways, and roofs of houses as impervious, and bare earth, water, and grass as pervious. To make sure that ArcGIS defines all surfaces correctly you have to manually define some of the surfaces so that ArcGIS has a reference. The image below shows the different samples that I defined so ArcGIS could be more thorough.

Results 

After running the wizard, ArcGIS recolors all bands into the color that you classified them as in the wizard. it becomes clear what is water and what is grass but there is some confusion about what is a road and what is a driveway. It's understandable because these surfaces are pretty similar. 

Even though there are some inaccuracies in this, it is still very useful for identifying where things are. One of the largest errors is a pond towards the bottom of the image that is classified as a roof. the tutorial walks us through how to correct this. First, you have to choose the reclassify within a region editing tool and draw a polygon around the pond. since the pond is pretty isolated it is pretty simple to redefine. The above result shows the usefulness of the band classification tool.