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:

 
  • include regardless of population level

  • exclude regardless of population level

  • allow Model to apply thresholds

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 Main Urban Areas 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.┬áThis 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:

   
  • flat size (average GFA per flat)

  • persons per flat

  • domestic floorspace occupancy rate

  • Development Site Area

  • Net Site Area

     

 

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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  2005 Copyright Important notices Last revision date : July 2016