Export to KML is an extension developed for ArcGIS by the City of Portland, Bureau of Planning ans Sustainability. The extension allows ArcGIS users to export GIS data in “keyhole markup language” (KML) format for viewing in Google Earth. Any point, polyline, or polygon dataset, in any defined projection, can be exported. Geometry can be exported as either 2D features, or 3D features "extruded" upwards by an attribute or z-value.Some other features: ability to incorporate ArcMap layer symbology into the exported KML; labeling of point, line, and polygon features;; "describe" individual features using the database attributes (support for HTML in layer and feature -- "balloon" -- descriptions); store database attributes as "schema" items (implements Schema and ExtendedData tags to improve the transferability of the output KML); animate using "time" attributes and KML time stamps; supports coordinate system transformations. Cheers!