Here in Pennsylvania, you should start by looking at the Zoning and Subdivision/Land Development Ordinances which vary from Municipality to Muncipality. Many of the questions on density, use, grade restrictions, setbacks etc, etc can be found in these Ordinances relative to the particular zoning district that the site is located in. This will at least get you started on the "As of Right" development potential within your designated zoning district..Potential to change zoning, obtain variances etc will be more involved, costly and risky (with great potential payoff) but it opens up a whole other conversation.
If you can develop a concept plan for the property based on Zoning and Land development ordinances, you can then estimate yield/size of building lots, comparable new construction outsale value and then work backwards from finished product costs to help determine retail value and then wholesale value of a building lot. Keep in mind that without bringing the site through all approvals, it will have a much different value as land with "potential" vs. Land that is "approved"
This is generally how it works in the PA area. It may be different in other parts of the Country...
I would verify all of the lot yield claims with the specific city authority that the property is located in and if it does truly have the claimed yield potential, you will need to figure out the probable product (and retail price) that would sell on these lots. The finished, meaning subdivided and approved lot value is typically valued as a percentage of the finished product value. This percentage varies based on buyer and market but it could be 20%-33% in my opinion but that may or may not include the site improvements (roads, infrastructure ) already being installed and in place.
After doing all of this THEN you can come up with a reasonable valuation for the dirt...
This is just my opinion and experience and others may tell you different but it's just another perspective....
