Research on the effect of urban expansion on agricultural land in ho chi minh city by using remote sensing method

VNU Journal of Science, E arth Sciences 24 (2008) 104-112
*

Research on the effect of urban expansion on agricultural
land in Ho Chi Minh City by using remote sensing method
Tran Thi Van*
In$titutefor Environment and Resources, VNU- HCMC
Reccived 11 April 2008; received in revĩsed form 13 July 2008

A bstract. H o Chi M inh C ity is a One of the biggest citics of V ietnam . B eíorc 1945, th e re vvore a b o u t
400,000 in h ab itan ts living in the City. D uring the last tw o decadcs, it b ecam e th e b ig g est in d u stria l
an d com m ercial center of th e country. A ccording to th e statistics in 2005, its p o p u la tio n w a s ab o u t
6.2 m illion poople. In th e su b u rb a n areas of the City, p artic u la rly in th e n o rth c rn p art, a g ric u ltu ra l
activities p ro d u c c tho m ain incom c of thesc local residents. W ithin tho last 15 ycars, d u c to
u rb a n iz atio n and em ig ratio n from o th er provinces, th e p o p u la tio n ex plosion b ec am e a serio u s
problem . T h e convorsion of agricultural land into residential a re a s h as incroased m o rc an d m ore,
causing th e change of lan d -u se structure. This p a p e r describes th e capability of re m o te scn sin g for
detecting a n d analy/.ing sp atial changes as w clỉ ns q u an tiíy in g rc su lts to sh o w th c u rb a n grovvth
process, an d its im pact on th e lan d -u se d istribution in the n o rth e rn p art of H o C hi M inh City.
Keỵĩvords: A gricu ltu ral land; GIS; Rom ote sensing; S uburban; U rban expnnsion.

result, an extrem c stress to the cnvironm ent
has occurred. This is particularly truc in Ho
Chi M inh City w here agricultural land has
been gradually d isap p carin g each year,
converted into urban or related uses.
Purtherm ore, because of the lack o í
ap p ro p riate land use p lan n in g and the
m easures
for sustainable
developm ent,

ram pant urban grow th is crcating severe
environm ental consequences.
A lthough Ho Chi M inh Citv has a history
of establishm ent and d cv elo p m cn t over 300
years, urbanization has just started from few
last decades. Ind u stry began to play an
im portant rolc m crely in 1960 - 1970 years
[6], and then som e urbanized regions w ere
obviously on the rise. H o u c v e r, the vvar had
caused
the
constrained
situation
of

1. Introduction
O ver the w orld/ the cities cover only
about one percent of the cartlVs suríace, but
m ost oí the issues h ap p en in g in the cities
greatly impact on thc environm ent and global
change [7\. U rbanization leads to urban
spatial expansion d u e to the dem and for
developm ent and housing grovvth, as vvell as
íacilities areas to serve hum an life.
In Vietnam, land use and land cover
patterns ha ve undergone a íundam ental
change due to rapid cconom ic developm ent
und er its reíorm ative econom ic policies.
Urban grow th has been speeding up; as a

*Tel.: 84-8-8651132.
E-mail: lranlhivarầ@>hcinier.cdu.vn

104


Tran Thi Van í V N U Ịourtĩìil o f Science, Earth Sciences 24 (2008) 704-717

urbanization vvith the great concentration of
huge population, w hile the in d u stry slowly
developed and living Standard w as still low.
From the end of the 1980s, Ho Chi M inh City
has really entered into the pcriod of
urbanization and w as speeded u p by
industrialization vvith íairly strong progress [6].
A griculture and rural areas belong to
general socio-econom ic stru ctu re of H o Chi
Minh Citv w ith their ad v an tag es of
geographical location exist as a su b u rb an of
the big scientiíic, technological, industrial and
com m ercial city. The city has taken full
advantages of location, exploited strength of
industry, Service, Science and technology to
serve the dev elop m en t of ag ricu ltu re and
rural areas. In recent years, d u e to the
requirem ents of city expansion, a part of
suburban agricultural land w as urbanized.
According to developing strategy for a
civilized/
m odern

and
environm ental
sustainable City, suburban ag ricu ltu re has
intended to tran sío rm into ecological and
high-tech agriculture.
If the urban and urbanization issues had
been studied for a long tim e in the w orld and
then still have been continued to study, in
Vietnam this problem m erely is on research
íocus from the m iddle of 90s [2]. The
monitoring of temporal and spatial changing
issues in urban is useíull for m an ag ers and
planners to dravv up a strategy for urban
suitable dcvelopm ent. Traditional m ethods
rcquiring extensive labour do no t bring the
eííectiveness in the rcgional scale becausc of
high cost oí íielci m easurem ents. Remote
scnsing and geographic iníorm ation system s
(GIS) has been w idely applicd and has been
recognized as a pow erful and effective tool in
dctccting urban lan d use and land cover
change [4]. GIS technology providcs a Aexible
environm ent for entering, analyzing and
đisplaying digital d ata from v ario u s sources.
It is necessary to identiíy urban íeatures íor

105

change detection and database developm ent.
Remote sensing technology can acquire on

the gro u n d obịects vvithout touching them.
Satellite rem ote sensing collocts multispectral, m ulti-resolution and m ulti-tem poral
data
and
turns
them
into valuable
iníorm ation
for
understanding
and
m onitoring urban land processes and for
building urban land cover datasets [8].
Especially, it is useíul to consider the
historical developm ent of a region. This study
uses the Landsat TM and ETM* to extract the
built-up land in the city and evaluate the
change
of
agricultural
land
under
urbanization in Ho Chi M inh City.

2. T he stu d y area
Ho Chi M inh City has a very íavorable
geographical location in the centre of the rich
Southern region vvith m any resources. The
city
has

the
com m on
adm inistrative
boundary with Long An, Tay Ninh, Binh
Duong, D ong Nai, and Ba Ria - Vung Tau
provinces. Its natural suríace area is about
209,502ha, am ong them
45% is the
agricultural land. The land of the city is
íorm ed by old and recent alluvions, having
poor fertility of soil, not suitable for
developm ent of annual crop production [5].
For historical conditions, Ho Chi Minh
City vvas íorm crly a kind of m onocentric city.
Beíore 1975, activities of econom y, íinance,
culture, education, com m erce vvere mainly
concentrated in District 1, 3 and a part of
District 5. Ho Chi M inh City has the íairly
rapid speed of urbanization. According to
statistics,
the
population
density
has
increased from 552 peoplc/km 2 in 1985 to
2,601 people/km 2 in 2002 (in urban areas
about 10,076 people/km 2, in rural areas about
602 people/km 2). N on-agricultural population
rate has signiíicantly increased from 83.3% in

Tran Tỉĩi Van / VN UỊournal o f Science, Earth Sciences 24 (2008) 1 0 4 -ĩĩĩ

106

1985 to 95.2% in 2002. The population grovvth
causing population overload in the city has
been shovvn not only by the natural increase
on the spot, bu t also by the mechanical
movem ent from other provinces.
As a result, there is an indispensable need
to im prove, expand and develop the old
urban areas in this situation. In addition, the
city som etim es has not controlled unplanned
constructions
and
urban
encroaching
expansion on suburban agricultural land in
the northern part. Thercíore, the study area is
íocused on this part. This is a region vvith a
lot
of
advantageous
conditions
for
developing inírastructure for residential,
commercial and industrial areas. H erc is the
place vvhere the urbanization process is
happening íairly strong in the recent years

(Fig. 1).

Fĩg. 1. T he stu d y area.

3. M ethodology
This study vvas based on rem otely sensed

data (satellite im ages), along w ith íields check
and existing m aps. Land cover p attern s for
1989 and 2002 w ere m apped by using
L andsat TM and ETM d ata (Dates: 16 January
1989 and 13 February 2002). Five types of
land covcr are identiíied and used in this
study, in d u d in g : urban, agricultural land,
bare land, shru b /g rass land and vvater.
As the íirst step, the data prc-processing
w as initiated for tw o im ages. The im ages
vvere geom etrically rectiíied and registcred to
the sam e m ap proịection to lay them over
each other for change detection. The im age
registration vvas careíully carried out w ith the
RMS errors less than 0.3 pixel to g uarantee
the tw o coincidcnt images. D ue to lack of
atm ospheric
m easures
d u rin g
im age
acquisition, the atm ospheric correction w as
ignored. H ow cver/ these im ages w ere
acquired in dry season (in January and

Pcbruary) in the study area, so they app eared
very clear and cloud íree. In this context, the
atm ospheric cííccts on these im ages were not
signiíicant.
In ordcr to obtain a high accuracy for thc
interpretation results, w e selected thc training
sam ples for each gro u p of speciíic object. For
each group (e.g. w ater) som e types of sam ple
w ere selected by the spectral signatures in the
im ages (e.g. vvater 1, w ater 2, etc.). The
M axim um Likclihood Classiíication w as
carried out for each image. A íter testing
several tim es to carrying o u t the classiíication
as well as ad d in g sam ples for achieving
higher accuracy, the íinal results w cre
accepted. F urther activity is the postclassiíication to group the íragm cntary results
in five m ain types of land cover as initial
determ ination. The coníusion m atrix vvas
calculatcd for the stu d y area after m asking
the unnecessary outside. The overall accuracy
vvas about 88% íor the year of 1989, and 86%
for 2002. Then, íor analyzing thc nature, rate


Tran Thi Van / V N U Ịournal of Science, Earth Sciences 24 (2008) 104-127

and location of u rb an expansion in com pared
vvith loss of agricultural land; an im age of
urban-residential area w as extracted írom
each original land covcr image.

The urban expansion im age w as íurther
overlaid w ith som e geographic reíerence
im ages to an alyze the patterns of urban
expansion, including im age of district
boundary, m ajor roads.

4. Results and discusions
4.2.

Urban expansion during the pcriod of 1989-2002

The
research
results shovved
that
population explosion w as the m ain cause oí
urban expansion. H o Chi M inh City is the
biggest industrial and com m ercial center of
V ietn am . T h e h ig h e c o n o m ic grovvth an d

107

ab u n d an t cm ploym cnt opportunities caused
inílux of labor im m igration. According to
general dem ographic investigation to ls t
April 2004, H o Chi M inh City had 1.8
millions im m igrants in the population total of
6.1 ĩ m illions. Local increase of population
plus im m igrants m ade the city becom e too
stuííy. According to statistics, the urban

population has increased 2 times írom 1990 to
2005. The population density in urban
districts in 2005 w as reported around 10,608
people per square kilom eters [1Ị. Due to
housing dem and and city developm ent,
agriculture land vvas transíorm ed into land
for houses, roads, industrial and commercial
areas.
From the source of the D epartm ent of
N atural Resources and Environm ent, the
main land use structure in Ho Chi M inh City
is shovvn in Table 1 and Fig. 2.

Tablo 1. M ain land use stru ctu re in Ho C hi M inh C ity o v er ycars
l.an d u se / Ycar

1 9 9 5 (ha)

2 0 0 0 (ha)

2005 (ha)

1995(% )

2000 (%)

2005 (%)

Total
B uilt-up land

A gricuỉtural Innd

209,376.00
31,196.34
100,366.37
34,657.58
34,153.02
9,002.96

209,502.00
38,571.07
97,247.78
33,472.15
34,011.29
6,199.54

209,554.00
50,523.72
89,659.21

100
14.90
47.94

100
24.11

33,857.86
33,250.02
2,263.67

16.55
16.31

100
18.41
46.42
15.98
16.23
2.96

Forest
W ater
U nused land

4.30

42.79
16.16
15.87
1.08

12
10
8
A rea (h a )

6
4
2

0
Built-up land Agricultural

Forest

Water

Unused land

------------------- land
.... ♦ .... 1995 ---- ------ 2000 --■ * ----- 2005
Fig. 2. T he ch an g cs betvveen b u ilt-u p land and agricultural lan d from 1995 to 2005 by statistics.


Tran Thi Van Ị VNU Ịonmaỉ o f Science, Earth Sciences 24 (2008) 104-111

108

O ver
the
vvhole city,
the
land
transform ation w as realized m ainly in the
northem part of the City as show n by the
results írom rem ote sensing data. Fig. 3
shovvs that the dense settlem ent presented a
rapid expansion and concentrated in urban
districts and along the m ain roads in the

suburban areas, vvhere the agricultural land
yielded to property developm ent Although
built-up areas have increased in all
directions, it w as m ainly concentrated in the

í
'

-4

.

(■

N orth, VVest and East of the city and along
the m ainroads.
Result of L andsat im age interpretation
show s that d u rin g 13 years, from 1989 to
2002, agricultural land vvas decreased by
39,329 ha, am ong which 6,045 ha vvere
changed to urban residental land, and 23,065
ha appeared as bare land since the local
íarm ers sold their lands. They vvill bc used
for íuture built-up purposes (sce Table 2).

4ị

"

•

?

*

■

r ộ V

*
. e ỉ

•
Ị

.

m

.

-

» > •

'i k
u r b a n

r b a n

V V a te r

-

a te r

B a r e

U

A g r ic u U u r a l l a n d

A g r ic u l lu r a l la n d
W

fv T Ỉ

ỳ V * '
H

■

B
la n d

S h r u b / y r a s s

a r e

la n d

S h r u b / g r a s s

l a n d

( a n d

1989

2002

Fig. 3. R esults of u rb an expansion in the n o rth e rn p a rt of H o Chi M inh City
in 1989 and 2002 from rem otely scnsed d ata.
Table 2. L and usc tran sío rm a tio n from 1989 to 2002 in th e n o rth e rn p art of H o Chi M inh C ity (ha)

lan d

Rovv total
(2002)

C la s s to ta 1

84.15

892.26

12,860.73

12,860.73

2,200.86

1,550.52

17,276.22

73,998.90

74,060.10

1,556.01

5,297.04

18.99

982.62

7,953.48

7,963.02

851.76

23,065.65

351.45

1,120.59

3,378.15

28,767.60

28,767.78

Shrub / g rass land

81.63

8,661.87

310.23

69.30

9,584.10

18,707.13

18,731.16

Class total (1989)

6,577.02

91,906.38

8,847.54

2,843.55

32,113.35

C lass changes

1,426.14

39,329.01

3,550.50

1,722.96

22,529.25

Im age d iííeren ce

6,283.71

(17,846.28)

(884.52)

25,924.23

(13382.19)

U rban

A gricultural
Land

YVater

Bare land

U rban

5,150.88

6,045.48

687.96

A gricultural land

393.93

52,577.37

W ater

98.82

Bare land

S h ru b / g rass

Tran Thi Van / V N U loum nl o f Science, Earth Sciences 24 (2008) 104-1 ĩ 1

By history, d u e to intensivc urbanization
in the suburban districts, such as Tan Binh,
Go Vap, Binh T hanh and District 8, residental
land becom es rnore and m ore cram ped.
U nder the íorce of circum stances, some
suburban areas w ore changed into íive new
urban districts írom 1997. D istricts 2, 9 and
Thu Duc have been divided írom Thu Duc
sub u rb an district; District 7 from a part of
Nha Be and D istrict 12 from a p art of Hoc
Mon. Beside that, th e d evelopm ent of thc nevv
urban areas such as N am Sai Gon helped to
extend Ho Chi M inh City in all directions.
As it is shovvn by the analysis of rem ote
sensing d ata in 1989 and 2002, the built-up
land increased m ost in districts Tan Binh, Go
Vap, Binh Thanh and D istrict 8, vvhere the
population is densely located (sec Table 3).
T able 3. B uilt-up land increase w ith p o p u ỉatio n
District

Incrcased
In crcascd
nrea
in p o p u latio n
b u ilt-u p
total
land (k m : )

Tan Binh

20.34
13.49
11.07

G o V ap
Binh Thcinlì
D istrict 8

8.25

324,904

Increased
p o p u latio n
pcr km 2

205,656

14,517.61
10,418.24

83,864
88,423

4,039.69
4,610.17

The change of agricultural land has
happened in the areas w ith available
inírastructure, n ea r m ain roads, in the
gatcvvay areas of the City, especially in the
areas planncd for residential, industrial,
commercial zones.
Effcci ofỉos$ of agricultural land due to urban
cxpansion

4.2.

Agricultural activities in su b u rb an areas
bclong to general socio-econom ic structure of
Ho Chi Minh City. From the Day of
Liberation in 1975, agricultural íields as the
city's green bclt have been changed on

109

general dem and oí city developm ent through
diííerent stages w ith mission of supplying
íresh íoods and a part of raw m aterials for
industrial Processing. Novvadays, rural areas
havc been charged vvith production of higheconom ic-value
agricultural
goods,
accom m odated m arket and export. In recent
years, d u e to thc needs of expansion of the
City, a part of suburban agricultural land has
been urbanized. Suburban agriculture has a

tendency to transíorm into ecological and
high-tech
agriculture,
according
to
developing strategy of a civilized, m odern
and environm ental sustainable city.
Hovvever, d u e to uncontrollably rapid
urban expansion in the year's 1990, loss of
agricultural land in rural areas has m ade a
change of the unplanned City. Agricultural
land in Ho Chi M inh City is not only limited
in the size but also is poor on quality due to
the alum -salted eííect plus uníavourable
conditions on topography and water. This has
inílucnced land exploitation potential on
goods oricntation. As conscquence, the
eííectivencss of agricultural land use in
suburban areas has a low er level in
com parison to the vvhole country. In addition,
the average norm of agricultural land
distribution for each household was very Iow:
0.32 ha per household, just equal 2/3 of the
average norm of the South-East Region and
equal 1/3 of the M ekong Delta. This situation
is a pressure on suburban íarm ers in keeping
agricultural production [6].
A ccording to the investigation of Institute
of Economic Research in June 1996, the
num bcr of íarm ers ovvned the crop land was

decreascd by 23% com pared vvith the total
land in urbanized areas [6]. Due to thc above
lim itations, plus the im pacts of urbanization,
these íarm ers w ould not hesitate to sell land
in o rder to m ake Capital for anothcr type of
investm ent. They hoped for higher proíits or


110

Tran Thi Van / VNU Ịoumaỉ o f Science, Earth Sciences 24 (2008) 104-111

im provem ent their life in the short term. As a
result, this circum stance caused the rapid
reduction of agricultural land. M ost of the
yielded land h a s been ch an g e d into the urban
uses. A lot oí new urban areas has rose jfor
satisíaction of housing dem and
from
population explosion. This m ade the city
íacing problem s of ecological unbalance and
loss of traditional agricultural villages.
Typically, Go Vap íloricultural village vvas
disappeared, now a few points of decorative
plant trade exist as the rem inder of this
tradition. Lovv land areas cultivating vvet rice
(such as in D istrict 2) naturally w ere places
for balance of the drainage, b u t constructing
and concretization process m ade flow to
convergent narrovv sevverages; or the altitude

raise
of
new
urban
areas
caused
concentration of w ater flow in lovver old
urban areas and instant inundation was
unavoidably h ap p en in g in the city centers.
Hovvever, it is w orth to m ention that aíter
land selling, the situation of fallowing
agricultural land has becom es w idespread in
suburban districts. This causes the prodigality
in land use of the city.

directions, b u t it was m ainly concentrated in
the N orth, VVest and East of thc city and
along the m ain roads. In the upcom ing years,
due to trend of expansion, H o Chi M inh City
vvill becom e a special urban vvith population
m ore than 10 m illions by 2010 year [3]. U rban
expansion supplied conditions to disperse the
habitants from excessive concentrated areas
of inner city districts. Hovvever, the
uncontrolled sale of agricultural land m akes
diííiculty
in land
m anagem ent u n d er
sustainable developm ent
In the íuture, it is required a huge am ount

of investm ent to im prove the productivity
and effectiveness of agriculture in the
situation of less rem aincd agricultural areas
w ith
bad
íertility
plus
uníavourable
conditions on
topography
and
vvater
resources. Finally, although urban expansion
cannot be stopped, vvith proper m anagcm cnt
and planning it can bc clirected in a desirable
and sustainable way, protecting fertile
agricultural land and ecological areas,
creating green belt for the city.

A ck n o w led g em en ts
5. C onclusions
In this study, rem ote sensing and GIS
m ethod vvas developed for evaluation of
rapid
urban
expansion
and
loss of
agricultural land. Results revealed a notable
increase in urban land cover betw een 1989

and 2002. Built-up areas has increased in all
directions bu t it vvas m ore concentrated to the
North, VVest, and East of the city.
U nder im pact of urbanization, land-use
types have suííered a lot of changes,
especially for the agricultural land. The
results from rem ote sensing data shovvn that
urban expansion has spatially increased in all

This pap er w as com pleted within the
íramevvork of F undam ental Research Project
719706 íu n d ed by V ietnam M inistry of
Science and Technology.

R eíerences
[1] B urcau of S tatistics in

H o C hi M inh C ity,

Stntisticnỉ yenrbook in 2005, Statistical P ublishing
H ouse, H C M C 2006 (in V ietnam ese).
[2] D am T ru n g P h uong,
Urbnn in

Vietnmn,

C o n stru ctio n P u b lish in g H ouse, H anoi, 1995 (in
V ietnam ese).
[3] Decisiotĩ of the

Primer M inister No. 1570/QD-TT$

nbout approual of mission to adịust the genernl


Tran Tìỉi Van / V N U Ịournaỉ o f Science, Enrth Sciences 24 (2008) 104-111

111

pỊanniny on construction of Ho Chi M inh City to
2025, H anoi, 27/11/2006 (in V ictnam esc).

in tìo Chi M inh C ity - A proposnỉ of críterion for

(41 P.M. H arris, S.J. V entura, T he intogration of

R eport of thc Scỉentiíic Project, Institute of

g co g rap h ic d a ta w ith rem otely se n se d im agery

Econom ic
R esearch,
HCM C
1998
(in
V ietnam ese).
[7] p. Vollinga, N. H erb, ỉndustriaỉ Trnn$formation:

to

im p ro v c

classiíication

in

an

u rb a n area

Photogrnmmetric Engineering and Remote Sensing
61 (1995)993.

supporting empỉoỵment situation to District 2,

Science Pỉan, IH D P R eport No. 12. Bonn: The

|5Ị In stitute of E conom ic R esearch an d D epartm ent

In tern atio n al H u m an D im ensions P rogram on

of C u ltu ro a n d Kníormation of H o C hi M inh

G lobal E nvironm ental C hange, 1999.
[8] Q.A. YVeng, Rem oto sen sin g - GIS cvaluatio n of

City, Economic o f Ho Chi M inh City - 30 year
construction

and

development

(1975-2005),

u rb a n expansion a n d

In stitu te of E conom ic Research/ H C M C , 2005 (in

te m p e ra tu re

V ictnam ese).

Internatiom ỉ Ịournnỉ o f Remote Sensing 22 (2001)
1999.

[6] N g u y en Thi T u at, The iĩììpnct o f urbanization
process OỈI the socio-economic change o f rurnl arens

in

th e

its im pact on suríace
Z hujiang

Delta,

C hina,