Applications in GIS (GIS 5100): Lab 7

In this week's lab, we had to use a DEM to determine which areas would be impacted by the sea level rise and to overlay this data with census information to decide the possible number of people that would be impacted by it. 


To obtain the two different sea level scenarios of 3 feet and 6 feet, I had to limit the raster processing only to Honolulu since this is the study area. I went into the Environment setting and selected the Raster Analysis which gave me the option to set the mask to Honolulu. After setting the mask, I created two different flood zone scenarios by using the Less Than tool. The tool created a grid with cells that show areas that are flooded with the value of 1 and areas that are not flooded with the value of 0. Once the rasters were made I was able to determine what the total area of the flood zone by multiplying the cell count of flood zone and the cell size. The flood elevation was created by using two different tools. The first tool that was used was the Extract by Attribute which uses the Lidar DEM as one of the inputs and the other input as the SQL expression of “VALUE” < 2.33. This tool gives elevation to the flood zone. To get the depth of the flooded area, the Minus tool was applied. The first input was the Flood Zone 1 which had the sea level of 3 feet and the second input was the alter Lidar DEM of the flood zone elevation. The results allowed us to see the sea level rise of 6 feet would look like in the flooded areas of Honolulu. If my calculations are correct, the first scenario of sea level rise of 3 feet will have the total area of 5,710,950m2 and the second scenario of sea level rise of 6 feet is 23,793,075m2.