Calculate Area

Our goal is to calculate the counties' area in Washington and determine the population density per square kilometre.

To use the workflow, download and run it on the KNIME Analytics Platform. For optimal performance using the Geospatial Analytics extension, make sure you are using version 4.7.4 or higher.

The population data was gathered from the "US2020 Census data" node, and the county boundaries of Washington were obtained using the "US2020 Tiger Map" node.

To begin, merge the population data with the county boundaries of Washington by utilizing the Joiner node. This can be achieved by selecting the "Make Census GEOIDs compatible to Tiger/Line GEOIDs" option in the "US2020 Census Data" node and using Geo_Id as the key to combining both tables through the Joiner node.

Our next task is to calculate each county's population density per square kilometre. This involves projecting the county boundaries using equal area projection into the epsg:8857 coordinate reference system within the "Projection" node, which allows us to determine the area in square metres through the "Area" node. Once we have this information, we can use the provided population data to calculate the population density per square kilometre in the "Math" node.

In the final step, we use the Geospatial View to display the population density of each county. When you move your cursor over a county, you can view its county id and the calculated population density.

External resources

• API key for US2020 Census data