PRECISION OF SCHMID'S AND SMITH'S METHODS OF ANALYTICAL EXTERIOR ORIENTATION

Abstract

The usefulness of studying analytical exterior or entation methods -is derived from the fact that these can become a, bests of photogrammetric control extension as argued by Oswal in his recently * submitted Ph. D . thesis r31. Schmldts and Smith's are well known methods of exterior or entattono but sufficient data Is still not available as regards- their efficiency and precision. This dissertation aims at collecting more practical data for these, methods.. The problem has been Introduced In Chapter I with -a brie' ,review of important ,avaIlsble methods. The geometry of the 'selected methods. Is described in Chapter 11. The bas data used In the n rest gat ins a Q obtained from Oswai'a mathematical pbo ograms [ 4 and details of these can be found from Chapter III, Details of the investigations appear In Chapter XV,. The methods have been tested for five different terrains where height variations are from 0, to 25% (in terms of flying height) .. Abundant ground control is available in each photogram. ` The Schmid's method- as described In Chapter II requiring ••& y three control points, been studied for types of control point distribution, while Smith's has been tested for only one type of control distribu. tion. The second type uød for the Schmid's method, has the controls situated entirely in"Fuperlap regi©nr, a situation that would occur in aerial triangulation., It has been found that the largest errors obtained are noglgibie being as small as the errors due ' to dimen. sional instability of photographic emulsIon. . The conclusions derived from the . i.nvestiga . tions have been presented in Chapter V. The inve tis gations show that both the methods studied are capable of high precision, but for the purpose of exterior- orientation based aerial triangulation Schmid's method is superior to Smith's method 40