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Appendix 2
SUM2 Model for Converting Plot Ratio
to Population Density (for reference only)
SUM2 is a computer program which has been developed
to convert building density to population and vice versa, using site or area specific
values for key variables. A data entry screen, illustrated in Figure A-2, presents labelled boxes for the variables, into which known or
assumed values can be entered. Default values are given for most of the key parameters,
and in the cases of flat size, persons per flat and G/IC facility thresholds, potential
alternatives are offered.
The input values to be entered are:
a) Flat size (average GFA per flat)
This can be entered in one of two ways: either a
discrete value can be entered manually, or a distribution of percentages of flats between
various suggested sizes can be entered.
b) Community centres
The need for these is likely to be affected by
possible existing or planned provision on nearby sites, three choices are given:
c) Schools
This can be entered in one of two ways: either a
discrete threshold value can be entered manually, or a choice made between a threshold
appropriate to the Metroplan Area or New Towns.
d) Gross Site Area (m2)
e) Excluded Area (m2)
The site area of any use or area within the GSA but
not defined within the DSA, such as slope, non-ancillary G/IC facilities etc.
f) Roadspace
The percentage of the non-road DSA which is required
for internal road access purposes.
g) Target population
h) Open Space
Hectares per 100,000 persons of open space to be
provided within the site.
Figure A-2
Data Entry Screen
i) Persons per flat
This can be entered in one of two ways: either a
discrete value can be entered manually, or the choice can be made between the average
values for the Territory, Hong Kong Island, Kowloon, New Towns and New Territories.
j) Design year
The year of expected first occupancy (up to 2001) is
entered. This determines the rate of decrease in the selected ppf if an area average was
selected.
k) Type of development
The percentage of dwelling units in high-rise and
low-rise buildings is entered. This affects the selected ppf if an area average was
selected.
l) Plot ratio
The input screen then indicates, where applicable,
the values for the key parameters which are calculated by the Model from the input data:
The output of the SUM2 Model as used for individual
sites is presented on an output screen as illustrated in Figure
A-3.
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Important notices