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" , CoO ...... = .= ...... = = = = Co:> <=> "-'- <=> ex:: ~ 4 ::l5 = = .2 // ( PI'JlCTlCilL INTERPRETl,TION OF MAP l,CCURACY SPJ;CIHCIIIIUN" 12 . 10 8 6 o o 5 10 . 15 20 ROOT - IiIEA" - SQUARE HORIZON1AL ACCURACY ,11::515, 1964 - 65 UAP SCAlE: 1/24,01Hl - , NO. % Tom TESTS '. 110 - TESTS PASSmS (90 "/0 WITHIN 40 fT.l 101 92 . L R;;J8E =19 fT. OR LESS 54 49 , R~SE =23 FT. OR LESS . 80 73 , , , r [ - . ~ Ri;\SE =24 FT. OR LESS '.84 76 . i P r R1;ISE=28fT. OR lESS 99 90 r r I! : ~ . I t HI q! . _ t t. r ~. r f 1 f I': ,ff . I !' ! [ il.U " t i I, ,r l " I , 1111 t! l Iii ' . t r : t f [ I \, i. , i f . ~'.. ,'. I . ' f r I t I [. r i ' f t! ~, lit . 'l r I l , I r i d t . . , .. -, .- r t t. P I I . .. I- . t i [ I I! (H11 t' [ t. I r ! , . 1- t f I : . t r I I ~ ~ t 25 30 ERROR, IN 35 FEET "Figure 2.--Distribution of, root-mean-square~error.values from horizontal . Ilccuracy tests. 1964-,65. . , , the project tested. In general. natural terrain ,has uniform slope only on level or gently sloping ground, where the last term of the formula is . close to zero. In practi~e. if there 15 con- siderable reliefJ the formula has to be applied point by point. This can be easily done by re~ vriting the formula in this manner: " , ... Evr . 0.3 C.I. Where Evr - allowable root-mean-square error in elevation based on residual errors at each point ~ ._(~) where er ~ residual err~r at each point .. e - bt vhere ~ . elevation error before '~orlzontal shift" a.llo~ance ' b:- 40 feet (for 1:24,000 Wlp) , I ' t. tangent of angle of slope: a.t tbt.' point . The computation-of the root-~e~n-square -: error using 'this system can be conveniently carried out in tabular form. . . . I " .' > '. , . ., , .. 'n '.. " . . , .