Calculating amount of landcover lost if sea level rises to 1m and 2m Contour Line using ArcMap

by Richb   Last Updated October 20, 2019 05:22 AM

I'm relatively new to ArcGIS Desktop 10.1 and stuck trying to understand how to calculate the amount of each land cover type lost if sea level was to rise to a 1m and 2m contour threshold.

Essentially I have created a basic map of land cover for an area adjacent to a harbor. I have extracted 0m 1m and 2m Contour lines from a Lidar-derived EDM (Using a =<2m query) and plotted them on the land cover map as seen below.Land cover and Contour Photo

I then tried using the intersect tool with both the land cover shp and contours shp but a very similar map was produced outlining essentially the same image as before, as seen below, the attributes table has included some more information but i'm not sure what to use in calcualting the amount of area lost if sea level was to rise.

enter image description here

Answers 2

In your case you should look at the areas below 1 m and below 2 m. You therefore need to create polygons based on your contour lines (or directly from your DEM).

Based on the DEM (e.g. from LAS dataset to raster), here are the steps :

1) reclassify your DEM into 3 classes (<1, between 1 and 2, > 2)

2) convert this to polygon (rasterToPolygon_conversion)

3) intersect those polygons with you land cover

The result will be new polygons with new geometry and the attributes from each input feature classes. With summary statistics, you can get a table with the area per land cover class in each height category.

step 1b : from the contour lines, you need to draw by hand a line that will allow you to enclose the space between two contour lines, then you can convert to polygons (feature to polygon).

Remark: conceptually, low areas not connected to water are not necessarily inundated. But you probably know what are the connections.

March 24, 2014 20:03 PM

You could use the Feature to Polygon tool for each of your contour classes, then use the Erase tool to remove the various landcover features (based on your contour/polygon class layer). Before running the Erase tool you might want to export several versions of the landcover polygon layer first so you have different versions to erase against.

March 24, 2014 20:08 PM

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