Appendix 1

Example of Use of Table 6 to Relate Plot Ratio and Population Capacity

Table 6 can be used to solve the three types of problem set out below:

[ Simple Table Format ]

The following examples illustrate how the graphs in Table 6 are used for each of the three types of problem (see Figure A1). It is assumed in these examples that an allowance will need to be made for the provision of LOS within the DSA but outside the NSA (see section 6.5).

Problem type 1: How much population can a given site area accommodate at a given plot ratio?

Example:	Given :	Site Area	14ha
		Ppf	3.5
		GFApf	50m2
		PR	6.5
	therefore	m2 GFApp	= 50/3.5 = 14.3
	and	NSApp	= 14.3/6.5 = 2.2

Strike a vertical line on the graph from 14ha on the X-axis. This meets the 2m² NSApp curve at population 32,000 and the 3m² NSApp curve at 25,000. The required population is therefore about 30,600.

Problem type 2 : What site area is required for a fixed population at a given plot ratio?

Strike a horizontal line on the graph from 20,000 population on the Y-axis. This meets the 4m² NSApp curve at 13.4ha, and the 5.0m² NSApp curve at 15.7ha. The required area is therefore around 14.1ha.

Problem type 3 : What Plot Ratio is required to accommodate a fixed population on a fixed site area?

Strike a horizontal line on the graph, from 10,000 population on the Y axis to meet a vertical line from 7ha on the X axis. These meet on the between the 4 and 5m² NSApp curves, say NSApp is 4.3m².

	NSApp	= GFApp/PR
i.e.	4.3	= 20/PR
therefore	PR	= 4.65

It should be noted when interpolating between the curves for NSApp that some allowance may need to be made for the fact that the intervals between curves are not regular. Otherwise minor discrepancies may result, compared with the correct values.

Figure A-1 Examples of use of total population by DSA chart