We often say that zoning is the single biggest non-natural factor in assessing development and land value.
Natural factors, like location, proximity to transportation, utilities and resources, existing topography, foliage, and site orientation can't be changed and obviously have a big impact on development ("location, location, location").
But the zoning determines what you can use the land for--whether or not you can build two stories or twenty, or a single-family house versus a housing complex.
So when people find out that we can provide them with zoning information, they want to know if we can help them assess the natural aspects of the site as well.
Because of these requests, we've added topography and site contours to all of the UrbanForm cities: Portland, Seattle, and San Diego.
Now UrbanForm users can quickly get a sense of slope and land grade; included satellite views also let you see the tree coverage from the latest available satellite imagery datasets.
Full disclosure: none of these things can replace a full survey, geotech, EIRs, and on-site visits ;)