calculation for area and valuation
Calculation for Area and Valuation
Calculation of area means the determination of area of the land surveyed.
Definition
Ordinates
The perpendicular distances from the baseline to the boundary of the land concerned ar called as ordinates.
Methods to calculate area
(a)Trapezoidal Rule
A base line is drawn. In this method the boundaries are assumed to be joined by straight lines. The area between the base line and the boundary is trapezoidal. The ordinates are drawn from the base line, at regular intervals. Sum of the area of each Trapezoidal gives the total area.
Method of solving
Let O1, O2,…On be the ordinates drawn at regular intervals say X.
Area of the Trapezoid 1 = x/2(O1+O2)
=X/2(sum of the ordinates forming the trapezoid)
+X/2(On+1 +On) where ‘n’ is the number of Trapezoids.
>sum of all the individuals areas give the total area
A=Σx/2{On + On+1}
=x[O1+On+1/2 + (O2=O3+…+On-1)]
Steps
>Sum the value of first and last ordinates.
>Calculate twice the sum of other ordinates.
>The total sum is multiplied by the common interval.
>One-half of the final products give the final answer.
Note: If any one of the last ordinates O1 or On or both are zero, they should not be omitted from calculation.
(b) Simpson’s rule or Simpson’s one third rule or parabolic rule.
The boundaries should be curved. The ordinates are established at regular intervals. This method is applicable only when the number of ordinates is odd.
Area of the portion 1 & 2 = area of the trapezoid with sides O1 and O3 plus the area of the curved portion.
Width of the curved portion is 2X respectively.
A1.2 = {(O1+O3)/2} 2X+2/3 *2X {(O2 – (O1+O3)/2)}
=XO1+XO3+4/3XO2-2/3XO1-2/3XO3
=X/3(3O1+#O2+4O2-2O1-2O3)
=x/3(O1+4O2+O3)
>if there are ‘n’ portion ‘n’ being even, then the sum of the area of ‘n’ portions is given by
A = X/3[O1+On+2(O3+O5+……+On-1) +4(O2+O4+…On)]
Note: In Simpson’s rule, if the number of portion is odd or the number of ordinates is even, Simpson’s rule is applied up to the last but one portion. The area of the last portion is calculated separately by using trapezoidal rule. Simpson’s rule has better accuracy.
Valuation
Estimation or calculation of the value of the various buildings or property is termed as valuation.
Purposes of Valuation: For buying or selling a property etc.
Factors affecting the value of buildings
>Type of the building.
>Area where the building is located.
>Condition of the building.
Definition
(a) Plinth Area
It is defined as the total covered area of a building. It is measured at the floor level.
(b) Carpet Area
The difference between the area covered by a room and the area of the halls of the room is called carpet area.
(c) Floor area ration (FAR)
The ration of the total covered area covered area (plinth area) on all floors to the area of plot is known as floor area ratio.
FAR = total covered area of all floors/ Plot area
(d) Volume to plot area ration (VPR)
The ration of the volume of building measured in cubic metres to the area of the plot measured in square metres is called volume to plot area ratio. It is expressed in metres.
Methods of valuation
(a) Valuation by plinth area method.
It is the easiest method used in valuation of building. In this method the value of unit area of the building is decided by comparing with another in the same locality at that time.
Steps for valuation
>Plinth area is calculated.
>Rate of unit plinth area id determined.
>Cost of the building is calculated by using the formula
Cost of the building = plinth area of the building * rate per unit plinth area.
Note: For buildings with many floors the total plinth area is the sum of plinth area of ground ans plinth area of every floor.
(b) Depreciation method
This is to valuate old buildings. The cost of land is not depreciated (i.e. actual value is taken).
Valuation of old buildings by depreciation methods
>Depreciated value of the building (DV)
=Initial value (1_Rate of depreciation/100)^n where ‘n’ is the age of the building in years.
>Rate of depreciation is taken as 1 for buildings of expected life of 100 years, 1.3 for expected life of 75 years, 2 for 50 years, 4 for 25 years and 5 for 20 years.
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