0The following phase of the interaction is a nitty gritty surveillance of the space to set up the best 


positions for the control focuses. 


At first, information from all potential sources ought to be concentrated prior to wandering into the field. Such information 


would include existing guides and plans, airborne photos and any past studying information of that space. 


Longitudinal segments might be drawn from the guide shapes to guarantee that views between control 


focuses are well over the ground level thus liberated from sparkle or refraction impacts. On the off chance that the overviews are to be 


associated into the public reviews of the country (Ordnance Survey National Grid in the UK), at that point the 


position of whatever number public review focuses as could be expected under the circumstances, for example, (in the UK) those on the GPS Active or 


Aloof Network, ought to be found. These investigations, frequently alluded to as the 'paper overview', ought to 


at that point be circled back to a definite field surveillance. 


This last cycle finds all current control in the space of interest, both nearby and public, and 


sets up the last situations for all the new control required. These last positions ought to be picked to 


guarantee clear, continuous views and the best noticing positions. The area of these focuses, and 


the kind of landscape included, would then impact the technique for study to be utilized to find their spatial 


position. 


Figure 1.4 shows control focuses A, B,… , F, nearby to be studied. It is needed to get the 


facilitate places of each point. This should be possible utilizing any of the accompanying techniques: 


(a) Intersection or resection 


(b) Traversing 


(c) Networks 


(d) GPS satellites 


E 


  1. F