The diagram of the scene should show the dimensions, size, and relationships of various rooms and buildings as well as the general location and important construction elements. In contrast to photographs, a sketch can eliminate items that are irrelevant or distracting. The sketch must be accurate and easily read and understood without detailed study. Several sketches should be done when multiple types of evidence are to be noted. All sketches should include information about the investigator, the case number, the full names of all who helped make the sketch or measurements, the location of the crime scene, a geographical orientation, and a legend. Possible types of sketches include a top view, a cross section, an elevation, and portrayals of specific details. Common measurement methods include coordinate systems, the baseline system, triangulation, and angular displacement. Photography, particularly color photography, and reconstruction of the scene are also important procedures. Photographs must be carefully recorded. Fire investigators need careful training so that they can record both definite and reliable information. Five references are listed.