Surveying
The sidereal day is the time interval between two successive upper transits of

First point of Libra
First point of Aries
The polar star
Mean sun

ANSWER DOWNLOAD EXAMIANS APP

Surveying
For mapping any country

Geodetic triangulation of greatest possible sides and accuracy is carried out
All listed here
Secondary triangles are further broken into third and fourth order triangles, the points of which are used for detail surveys
Primary triangles are broken down into secondary triangles of somewhat lesser accuracy

ANSWER DOWNLOAD EXAMIANS APP