The first section of data in the tab is used to define the following information: Output Projection, Spheroid, Zone Number, and Datum. The default data displayed is the same as that used to define the block file. Selecting the Set button allows you to specify a new output projection, spheroid, and datum to be associated with the extracted DTM. Selecting the Set button displays the Projection Chooser dialog, which is used to input the new projection, spheroid, and datum. Once the new projection has been defined, it displays in the General tab.