Below you will find images shown in three individual scaling factors, x=2,8,16, represented in both true colour and false colour. In order to produce an image with these thresholds, we needed to use the raster calculator to compute the equation located on the right.
For the purpose of this assignment, I have chosen to use a thresholds of 16 to extract my roads. In true colour across all three scaling factors, pixels that represent roadways appear to similar to other pixels in the images. This would make it difficult to differentiate between roadways or other features. In the false colour images, the roadways are most dominant in scaling factor x=8. For a visual comparison when extracting roads, I do not recommend using images in true colour or false colour. Edge detection works best when viewed in grayscale, like we saw on the Scaling Factors page.
For the purpose of this assignment, I have chosen to use a thresholds of 16 to extract my roads. In true colour across all three scaling factors, pixels that represent roadways appear to similar to other pixels in the images. This would make it difficult to differentiate between roadways or other features. In the false colour images, the roadways are most dominant in scaling factor x=8. For a visual comparison when extracting roads, I do not recommend using images in true colour or false colour. Edge detection works best when viewed in grayscale, like we saw on the Scaling Factors page.