Geography 176A

Question 1

Identifying the Area of Interest

Our area of interest is Palo, Iowa. We filter to this city and create a 5 km buffer. We then extract flood data to this extent.

Question 2

Identifying, Downloading, and Caching Images

Dimensions, Coordinate Reference System, and Resolution of stacked images

Dimensions of the stacked image

## [1] 7811 7681    6

Coordinate System of the stacked image

## CRS arguments:
##  +proj=utm +zone=15 +datum=WGS84 +units=m +no_defs

Resolution of the stacked image

## [1] 30 30

Dimensions of the cropped image stack

## [1] 340 346   6

Coordinate System of the cropped image stack

## CRS arguments:
##  +proj=utm +zone=15 +datum=WGS84 +units=m +no_defs

Resolution of the cropped image stack

## [1] 30 30

Question 3

Making RGB plots of these images

Applying stretch = “lin”

Applying stretch = “hist”

Applying a color stretch helps make differences in landscapes more visibly clear to assist in identifying patterns or features.

Question 4

Assessments of Surface Water Features Using A Threshold Value

Raster Algebra for 5 Formulas Assessing Surface Water Features

The images are similar in that they highlight the river region as well as other surface water areas. They also all use the the same blue, white, and red color scheme that we created in our palette. They differ in that the surface water areas are not all highlighted in the same color, and some images direct more attention towards the landscape rather than water regions. The final plot, the simple water index, highlights only the surface water captured in the image.

Raster Thresholding

By applying five different raster thresholds assessing surface water features, we are apply to plot flooding areas in blue.

Question 5

Supervised and Unsupervised Classification Using K-Means

In this method of creating a flood raster, we calculated the cluster of most flooded cells in our kmeans data to create a flood mask.

## [1] 340 346   6

Question 6

Comparing the Different Methods of Creating a Flood Raster

Total Area of Flooded Cells
	x
ndvi	5999400
ndwi	6490800
mndwi	10745100
wri	7622100
swi	13680900
layer	434700