248 Qvjjru al'Qyy 2ai.fil.iQxV b\.iQxX Qcq ^aj f QviPU aI 'QYY 2al-fil.jQxY b'l.iQxx Qa\ j«.\ j j>. (34) QvLiVi j i {ai.iauQyY (ai.fii.j ai.fii.i) Qxy bi.fii.jQxx If the distances between the orientation points mutually and between the occupied station and the stations are chosen so as to be approximately equal, these assumptions would be less sweeping than the immediate introduction of the relative standard circle as an estimate of the relative precision of two points. The same reasoning as in the preceding section can now be applied to the equations (34), this time considering the relative standard curve of the occupied station I and the orientation stations instead of the standard curve of the occupied station I only. The same formulae (23) to (30) inclusive would apply. In practice there are mostly no other means to estimate the relative standard curves than as circles of a radius R c ][2d (35) where the correlation can be ignored. The c is a constant pertinent to the region of the control survey and d the mean distance between the occupied station and the orientation stations (numbered I and i, j respectively). It is then seen by substitution of c 1 and D o in (23) and (24) that A B A +B tan <pt A +B and tan <p2 _g since now Qxx Qyy and Qxy 0. Consequently 9i 9i 7 9a 9i- (36) 4 The expressions (25), (26), (29), (30) and (31) can be simplified accordingly. They become respectively *1 d, yi (37) and dl d2 ds dy (i y 2). (38) Referring to formula (12) it is seen that all terms vanish where the coefficients ca and Cj occur. We still have to attend to the influence of the third term of formula (11) viz. TZ 91 92 - and also

Digitale Tijdschriftenarchief Stichting De Hollandse Cirkel en Geo Informatie Nederland

Tijdschrift voor Kadaster en Landmeetkunde (KenL) | 1963 | | pagina 16