Where can I get measurements of a given area using the orthophoto?
While you can get a coordinate readout from the Land Survey Information System (http://www.geocommunicator.gov), we did not add any analytic or measurement functionality to the system, in the interest of keeping the interface as simple as possible. If you need to obtain measurements from an orthophoto, there are other tools such as ArcView or ArcExplorer (free) that would be more appropriate to use. You can get the free viewer from: http://www.esri.com/software/arcexplorer/index.