I generated a flood hazard map(raster) of a certain area using ArcGIS 10.5 and classify the result into low (0.1-0.5), medium (0.5-1.5) and high (1.5- up). After that I overlay a Land Use map(polygon) in order to identify affected areas.Now, I want to count the area occupied by each classes with respect to the land use map. Can anyone suggest methods for that?
You could convert your flood hazard raster to polygon using the "Raster to Polygon" tool. You can then interest this with the Land Use vector file and calculate the areas of each using the "Calculate Geometry" function in the attribute table.
What you need to use is Tabulate Area tool. In fact, this a direct application of Tabulate area tool, but it requires Spatial Analyst extension:
in_zone_data: Use the land use as input zone feature,
zone_field: choose the field that defines the land use
in_class_data: use the flood reclass raster data that will have their area summarized within each land use zone.
class_field: The field that holds the flood class values.
The output will be a table that gives the total area of each flood class within each land use zone in meter assuming your data are in UTM projection.