How to Build a Developable Land Map in ArcGIS Online Many local governments publish their parcel data online. A quick search for “parcels” We want to map land value, but it’s a text field. Maybe we can convert it to a number and map it. Let’s go to a street and look at some parcels. This blog discusses this style of map, and how to convert text into numbers. Read about and copy this simple Arcade expression. Scroll down to choose “New Expression” Paste the Land Value expression. The expression converts text to numbers, and handles divide by zero cases. Name the expresssion as you want it to appear in the map legend. The values are instantly calculated. You don’t need to own the layer to create and map this data on the fly. Choose the “Above and Below” theme The land can be anywhere from 0 to 100% of the total value. We spread the color ramp such that 50% earns the “middle” of the color ramp, while the extreme values earn the darkest colors. A brown to green color ramp clarifies which parcels are mostly land value (brown) or improvement value (green).