1. LSGI 4321 Essay Topic
Critics have argued that the roof of the current high housing price is the result of a mismatch of supply
and demand. Discuss how GIT can help facilitate a steady housing land supply to meet the demand.
Tang Wing Yee Peony 09113226D
Introduction
The housing price in Hong Kong nowadays is
continuously increasing. Although the government has
introduced some new housing policy and increased the
restriction on property transaction and the economic
environment is still full of uncertain factors, the
increasing in property price is still having an adorable
raise. Therefore, both the middle and lower income
classes can hardly afford to buy a place for living and it
leads to social disharmony.
Some said that if the government can ensure a steady
land supply, the current housing price may be reduced.
In this essay, I will discuss how Geo-Information
Technology (GIT) can help facilitate a steady housing
land supply to meet the demand.
Defining GIT
GIT is a mean for spatial analysis. It consists of both specialized information and communication
technology. Data includes resources, landscape features and socio-economic characteristics of an area
will be collected, managed and analyzed. It can then visualize the spatial data for communication,
dissemination and knowledge sharing. Its major tools are Geo-Information System (GIS), Geo-positioning
System (GPS), remote sensing and web-based tools.
DefiningLand Supply, Land Capacity and Demand
Naturally, the contentiousness of a highly politicized process that helps shaping the decisions of the
development of urban increase according to the relative scarcity of land deemed “developable.” This
need to establish “definitions of available land supply agreed on by both private interest and the
government” continues to be a major issue with land monitoring.
Typically, buildable lands are classified as vacant, partially utilized or underutilized. Vacant land is land
without any significant uses. Partially utilized land is improved parcel that are sufficient vacant and allow
additional new construction without changing the existing structure. Underutilized land is property that
already developed over most area, but considered likely to undergo demolition and replacement or

2. significant alteration of structure to yield more intense, more highly valued, or altogether different uses,
usually means lands having redeveloping potential.
Although adequate land supply is always assessed relatively to demand, it technically does not have to
be considered in determining the land supply and estimating the land capacity.However, if possible, we
should also consider the consumer preferences for housing type, sectoral employment growth, and
changes in construction and land development practices as well as dwelling unit versus employment
growth.
As for Hong Kong, the land supply mainly sourced from government vacant land and renewal project,
while the purchasers of the housing are usually investors and residents.
Trend of using GIT in monitoring land supply
Recently, there is increasingly more concern on the impacts of future urban development through
growth-conscious planning and the development of GIT become more rapid, which helps doing the
functions of planning and management. Since GIT is capable in perform several of functions that help
doing sophisticated analyzes, modeling and visualizing, use of GIT in monitoring land supply becomes
more common and popular.
How GIT facilitate the land supply
Data Capture
Before the processing, we need to develop a comprehensive land supply database, conduct an inventory
of the buildable land supply, estimate development capacity and apply land supply and capacity
information to plan-making and plan implementation processes.
Since the data collected are useful to other general planning activities and other government functions,
also the monitoring and analysis approach may change over time, so it is important to separate the
database from the buildable land supply inventory and analysis. The database should be as completed
and comprehensive as possible, if not the outcome may not be reliable and convincing.
Generally, the database should include the following data types such as existing and planned land uses,
zoning, other regulations that impose limits on density and use (usually imposed by the planning
departments of the government to ensure a sustainable city development), land ownership information,
environmental conditions, existing planning and infrastructure, etc.
Remote sensing, one of the essential GIT tools, is definitely capable in collecting most of the above
information. Remote sensing is the art and science of obtaining information about object, area, or
phenomenon through the analysis of data acquired by a device that is not in contact with the object,
area, or phenomenon under investigation.
Using remote sensing, we can do land use classification, land use monitoring and environmental
observation.

3. By image interpretation, we can do land use classification according to their shape, size, pattern, tone or
hue, texture, shadow, site and association. For instance, texture helps distinguish urban and rural land
use. Shape helps recognize recreational land use such sport ground and swimming. Site, which is the
geographic location of the features, can help recognize commercial land use such as Central. Pattern
helps us to distinguish residential and industrial land use. We can also recognize transportation land use
such as roads and bus stations using pattern and association. More, it definitely helps us to identify the
vacant land and partial utilized land.
By image interpretation, we can able to monitor
the current use of land. This is really important,
since if the land is used not correctly, the
planning that done previously will be
meaningless and the ordinary land supply
strategy would be ruined. For instance, illegal
farming activities on government land like
mountain or national park can easily be
recognized using aerial photo using pattern.
Another example is that previously, that was
news reported on July that some riches built the
gate of their houses on government land and it
shows clearly on aerial photo and posted on
newspaper and TV program. (For more
information, please visit the following website:
http://www.hkatvnews.com/v5/news.php?id=151601&d=2011-07-18&cn=0)
Another application is that using different bands, we can able to observe the natural environment in
many different aspects. For instance, using visible blue band, we can illuminate materials in shadows,
observe the water penetration of bathymetry, soil and vegetation differentiation and deciduous and
coniferous differentiation. Using visible green band, we can observe water penetration for bathymetry,
clear and turbid water contrast, discrimination of oil on water and the green reflectance peak of healthy
vegetation. Using visible red band, we can observe the vegetation differentiation and chlorophyll
absorption.
Data Processing and output
By inputting the information captured to GIS, the system will do visualization according to the spatial
data. User can choose to build 2D or 3D model depends on their need.
After developing a
comprehensive land supply
database, we can then conduct
an inventory of the developable
land supply by delineating the

4. geographically specific and unit of land. As some lands may be excluded from the buildable land supply
even they are vacant, partial utilized and underutilized land. These constraints include environmental or
physical factors, land ownership and lands that use for specific purpose.Recently that is a buildable land
that its development is for prohibited since this land is being classified as a historical heritage. By
inputting all these requirements of buildable land and set up the formula, GIS would perform the data
analysis and it will able to identify the buildable land and select them in the model. Since the model is
visualized, it is possible for user to locate the buildable land easily and provide you the estimated
development capacity.
GIS is also useful in doing model
simulation. As to lower the housing
price, the government has been
introducing new housing policies and
adjusting the housing strategy. By
changing the value such as changing
in land ownership after ending of
short tern tenant treaty, increasing
the accessibility and infrastructure of
a place, and then inputted them in
GIS, the system can help visualize
the new look of the studied area, do
the analysis about the influences on
different aspects such as sky view,
ventilation, shadow, etc. as well as
the increase in land supply in a fast
way. Using this would be convenience for the government to introduce effective strategy or guidelines
that increase the land supply but at the same time minimize the harm that caused to the surrounding
areas.
Potentially, the land demand of Hong Kong will keep increasing, especially for residential and
commercial uses. Since land resources are limited, therefore different land usages are competing with
each other. Therefore, it is essential for the system to consider both factors. Since GIS can perform
assessment of potential amounts, pattern, and locations of future development within sub regional
areas of interest, it can definitely to forecast the future land demandand thus enable us tofacilitate a
steady land supply in long term.
Data Sharing
Web-based tools are very useful GIT tools for data sharing.
They includes Google map, GeoInfo Map, etc. Using this
information can be shared internal or to the general public.
They would be spatial information like addresses and site
annotation as well as analyzed result such as transportation

5. path from one location to another and area of a building. Through this it is possible for everyone in the
society in monitoring the land uses and comment on it. And the government may then able to receive
good and professional suggestion or recommendation from non-government institution such as the
Hong Kong Building Environmental Assessment Method Society.
Another point is that some web-based tools can be running under an open-source system, which
enables all people that able to access to the internet to alter and update the existing information. This is
good for obtaining the latest information using less cost and time, thus, produce a system that reflect
the current states for land supply monitoring. However, if the information is invalid, it would be time-
consuming to detect it and it may affect the accuracy of the system.
Limitations and Challenges
One limitation of using GIT to facilitate a steady land supply is deal to the capability and the accuracy of
the data. Since some information required may be confidential, private or lost, it is hard, costly and
time-consuming to establish a completed and comprehensive database and so the updating. Also, the
accuracy of the data collected may not be that precise, this is because the resolution of the digital image
is bad that affect the image interpretation, the site knowledge of the image obtainer is low and the data
captured may not be updated. All these will then affect the usefulness of the model in monitoring the
land supply.
Another limitation is that resources should be continuously inputted for the system maintenance.
Although the version of GIS system is being more and more advanced and providing users’ without more
functions, it is very costly and the users’ may need time to adopt the new system.
Also, since human behaviors are difficult to predict as well as the market conditions. It is hard to define
the term “steady land supply that meet the demand”. And the prediction of the future trend may
therefore be less powerful and can poorly support the quantitative and qualitative analysis based on it.
More, it is difficult for the system to address both the cumulative and dynamic aspect of environmental
impacts and constraints in urbanized areas. Although the responsiveness of the system to
environmental condition can be increase by including mapping of pollution “shed” around future
transportation and industrial concentration, monitoring land development within watershed, providing
data to estimate the cumulative impacts of development on land cover and soil permeability, research is
certainly needed in this area.
Conclusion
All in all, GIT would certainly help facilitate a steady land use that meet the demand. However, just
researches and developments on GIT tools must carry on. And the problem of obtaining a completed
and comprehensive database is still hard and seems impossible. Therefore, although people can use the
analysis’s result of GIT as a supportive evidence in new policy that help increase the land supply, people
should not fully depend on it and should do more consideration before any decision making based on
the result.

6. References
Anne Vernez Moudon and Michael Hubner, 2000, Monitoring Land Supply with GIS
Lillesand and Keifer, 2009, Remote Sensing and Image Interpretation
Info resources, 2007, http://www.inforesources.ch/pdf/focus07_3_e.pdf