High Resolution 1:10,000 scale Mapping Strategy of Multi ... - NDMA

way monuments or control points. This will permit orienting the maps to plan
stationing and plan right of way lines.
Targets shall be placed in the median and shoulder zones of the roadway in question
and on flat ground whenever practicable. Steep slopes, sharp ridges and ditches
should be avoided. All targets shall be placed on contrasting background so as to be
readily distinguishable in aerial photographs.
Each target shall be placed with its center directly over and at the exact elevation of
the steel rod or other appropriate manifestation of the control point in question.
The target legs should not slope appreciably from the center.
Normally, target spacing shall be at an interval equal to one-fifth (1/5) the flight
height. However, for those projects where the required flight height is 365 M or
less, targets shall be placed so that at least two (2) will appear in the overlap
between adjacent photographs. The recommended guidelines for sizes and centerto-center
intervals of white targets shown in the table given below. The linear
dimensions of a black target should be two to three times those tabulated below to
allow for image spread in the aerial negatives.
MAPPING
SCALE
FLIGHT
HEIGHT
MAXIMUM
INTERVAL
TARGET LEG
WIDTH
1:300 459 M 110 M 0.15 M 0.6 M
1:500 612 M 192 M 0.15 M 0.9 M
1:1 000 1 285 M 384 M 0.20 M 1.5 M
1:2,000 2 570 M 768 M 0.46 M 3.0 M
Table App 8.2: Design Guidelines for White Targets
LEG LENGTH
Target shape shall be in the form of either a symmetrical cross, a "T”, or a "Y" in that
order of preference. The stem of the "T" and each leg of the "Y" shall be equal in
length to one half (1/2) the recommended leg length. Targets shall be prepared by
painting or printing them on cardboard, muslin or similar cloth, or they shall be
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