Still this chain surveying, compass, leveling, theodolite survey is available in the practicals of civil engg. But we used only 20cm(one link) chain with 150 links or 30cm (one link) chain with 100 links. Soon these survey's will be replaced by the Total survey station instrument.
The chain survey was the concept of british and there were different types of chains available then.
But why this topic is here? This is a type of land measurement, but you need a scale (Like Thachu muzham) i.e. Ratio to plot your surveyed measurement on the layout.
Example: Scale- 1:1000 means 1000mm is actual measurement will be 1 mm in the layout.
If you measure 10mm from the layout using your scale it is 10000mm(10m) in actual.
Ratio and scale are different. Scale is amplification/reduction factor to represent big or small figures for manageability. In Hampi, there is a scale model sculpture of the YogaNarasimha with Lakshmi sculpture. The model is about a foot compared to the full sized one of over 15 feet. Perhaps the miniatures were made to get the approval from the king, or to convey the artist-sculptor's idea to the those doing the scuplting or to ensure that the work was completed even after the death of the master scupture.
Ratio is the geometric proportion to be maintained as per agama sastras; here the basic dimenson is not important. There are elaborate rules to decide the shape and relative dimensions of the geometric figure.
I am of the view that there was no standard size (as we have today - 1 metre etc.) . The basic measure was chosen on a random basis - jann, muzham, height of the king or an important person, and marked as a reference measure.
Scale is used in maps and we use it very much on a daily basis. A distance of 1cm on the paper map can be 1 KM on the ground. So you can draw a map of 10 Sq.Km in a 10 Sq.Cm paper. In case of sculptures, a proto (proto and model are not different) can be sculpted in a 10 Sq.Inches panel where as on approval, the actual sculpture can be 15 ft tall. The similarity between the proto and the actual will be that, the proportions are maintained. For eg. if the hand is 1 inch and leg is 2 inch in the proto, the actul can have the hand as 10 feet and leg as 20 feet, but the ratio of hand : leg will be alway 1 : 2, whatever be your measure...let it be inches, or cm or meter or km or mile or whatever.
Where as The scale under discussion is the basic unit of measure, like Meter or Feet, and you use the multiples of this base measure to built the actual structure. For eg. if the base measure is 1 meter, the height of the vimanam will be measured in meters and we can say 234 meters high or 50 feet wide and 30 feet long etc.
If I am correct, each temple has its own basic measure,and the lenght, breadth and heigh are in multiples of the base measure.
But what I feel, once the base measure is fixed you can easily calculate the height, lenght and width of a temple, the vimana height and gopuram height etc., because I have read in a book that there are some standard sizes for the temple structures. But I dont know whether those standards will be applicable to big temple and GKC, because these temples are totally different from the others.
Satish, pithy, precise explanation. I also agree with your statement that each temple has its own basic measure. The base unit is decided by the sthapathy - derived from the king's/sponsor's suggestions or from local religious customs. I read about it long ago, but it is now difficult to trace references. Sampath