Apparatus and methods are provided for mapping out endoluminal gastrointestinal surgery, including endoluminal gastric reduction. Mapping is achieved by locally marking the interior of the gastrointestinal lumen at specified locations. In a first embodiment, the surgical map comprises localized RF scarring or mucosal ablation. In an alternative embodiment, the map comprises pegs. In another alternative embodiment, the map comprises dye and/or spheres injected into at least the submucosa. As a still further alternative, the map may comprise the shaft of an endoluminal surgical tool having specified dimensions and/or color-coding, etc. In another alternative embodiment, the map may be formed from surgical mesh. In one preferred embodiment, placement of the map is accurately achieved by approximating the interior of the stomach with an endoluminal support via suction ports and/or via an inflatable member disposed along the support. Methods of using apparatus of the present invention are provided.