Frontier conurbations:
rather than twin cities, a symbiotic outcome
of two national cultures and identities
Andrea DA COSTA BRAGA
Décio RIGATTI
Claudio MAINIERI DE UGALDE
Fábio ZAMPIERI
PROPUR - Programa de Pós-Graduação em Planejamento Urbano e Regional
Faculty of Architecture / UFRGS- Universidade Federal do Rio Grande do Sul / Brazil
Santiago do Chile – January, 2012
TARGETS
 To explore the role played by cultural differences in shaping
the spatial structure of emergent international conurbations;
 To describe the spatial configuration regarding urban spread,
potential movement and land use allocation ;
 To identify configurational distinctions due to national social
and cultural codes;
 To discuss the typical features of Latin American and Brazilian
urban configurations found on the conurbations emergence;
 To focus broadly at the Conurbation Index (CI, as in RIGATTI,
2009) strength in order to verify continuity and connectivity
efficiency in fusion processes between the cities beyond
contiguity.
METHODOLOGY AND TOOLS
Space Syntax theory / methodological tools provided evidence on the
conurbations structural and morphological peculiarities, highlighting
typological differences and dominances emerging from a single urban grid
produced by two national societies.
Axial maps (HILLIER & HANSON,1984): processed using MindWalk® (FIGUEIREDO, 2002) tools;
Accessibility hierarchy / grid deformation spatial description : co presence patterns
(locals /strangers, HILLIER and HANSON, 1984) and movement potential (HILLIER et al, 1993);
Syntactic measures applied: Global (Rn) and Radius Radius (RR) Integration;
Correlations: Integibility / Synergy / Fast Choice Map (HILLIER et al,1987) used to identify
distinctions in national social codes and consolidation of centralities;
Brazil and Latin America urban typology (MEDEIROS & HOLANDA, 2007): comparison between
urban spread peculiarities to Brazilian & Uruguayan societies ;
Conurbation Index (IC= R / Σ (Rn/n), RIGATTI, 2008): contiguous urban grids structures
interpenetration formed a new kind of spatial system by comparison of Syntactic
compactness indicators Rn, Mean Depth, Integibility and Synergy.
IC > 1 = strong conurbations. Meaning that syntactic measures tend to be more
robust for the whole conurbation system than for its parts. Their spatial patterns and
urban dynamics are better explained if taken as a whole system . The spatial
structure logic laying in the core of the conurbation process (RIGATTI, 2009, 2011).
CONTEXT & HISTORICAL BACKGROUND
•
•
•
•
•
The region has been in disputation since the
18th century, therefore the founding of mirrorlike surveillance settlements along the
borderline: a village built in Brazilian territory
caused the rise of an Uruguayan one opposite
to it, and vice-versa;
The efforts to restrain permeability and
vulnerability on both territories caused the
recurrence of twin-cities phenomena along the
borderline (there are 6 of them);
Social and economical practices followed
advantages perceived by locals, disregarding
political struggles between Nations. That
configured a frontier territory and a
transnational “way of life” through commerce,
seasonal work and social networks;
Insulation from Brazilian most important towns
and easier communication with Montevideo
caused regional economical and cultural
linkage to Uruguay and Argentina;
The frontier social pattern of interaction and
coexistence is marked by a pretense invisibility
or unawareness of the stranger (here as in
HILLIER & HANSON, 1984).
Brazil / Uruguay borderline
is 1006Km long, settled in
1848, after the recognition
of Uruguay as an
Independent Nation.
Map of the landmarks limiting Brazil and Uruguay
source: www2.mre.gov.br/daa/uesc/html
BRAZIL / URUGUAY FRONTIER CONURBATIONS
CHARACTERISTICS
LOCATION
Chuí / BR
33º 41’32.35”S
53º 27’22.10”W
Altitude: 16m
•
•
Santana do Livramento /BR
30º 53’31.49”S
•
55º 31’57.05”W
Altitude: 211m
•
•
•
•
•
•
sources: Ministério do Interior –BR IPEA / Google Earth
Continuous and porous urban grids
without geographical barriers;
High permeability through / around both
settlements;
Non ostensive checkpoints nor built
barriers;
Intense / fuzzy movement of Brazilian
and Uruguayan nationals across the
border;
Complementarities in commerce and
services / shared centralities;
Exchange rates fluctuation between
currencies mediate transnational
interchanges;
Fluidity between strangers / inhabitants
marks co-presence & movement;
Configurational differences due to
national social codes / cultural identities.
A stretch of non aedificandi land runs
along the borderline, separating the
doubled street system on each side.
CHUÍ / BR – CHUY / UY CONURBATION
images: CBERS / INPE-BR, Google Earth top down: © Ailton Avila / © Margi Moss / © Prefeiruta do Chuí - BR
BASIC DATA
Settlement
Foundation
Municipality
Department
Geographical area
Distance to
Montevideo
Distance to
Porto
Alegre
Acessibility
Urban
population
Urban
area
CHUÍ
BR
1927
Chuí
(2000)
340Km
515Km
BR 471
5697
inhab
9,370
sqKm
CHUY
UY
1888
Rocha
Brazil
Southernmost
point
NE Uruguay
340Km
515Km
Ruta 9
9804
inhab
8 sqKm
GENERAL DATA ON CHUY (UY) / CHUÍ (BR)
•
•
•
•
•
Both cities were founded as commercial entrepots. Commerce
remains the main economical asset, anchored by Chuy Duty
Free Zone / Chuí wholesalers suppliers;
The region, once Neutral Fields (until 1814) was insulated from
the rest of Brazil territory until 1970, when BR 471 road was
opened. From 1930 until then, both cities were linked to
Montevideo through Rutas 9 / 19;
Chuy / UY was built earlier, to populate the area with
Uruguayans and minimize Brazilian appropriation of rural land
in Uruguay territory;
The conurbation is small and urban spread is constituted
almost of low income dwellings meant to absorb migrant rural
population on both sides of the border;
Infrastructure problems are remarkable.
Chuy / Chuí peripheral position is undeniable
Top – down: Chuy /UY main square / the end of Brasil – Uruguai avenues (SO) along the borderline / Numancia st in connecting to
Brasil avenue (CHUY) / Brasil-Uruguai avenues where it crosses the cities centers / rua Argentina - CHUI-BR links both cities cores /
a new Duty Free Shop next to 669 road (leading to the shore) SE – CHUY images: by the author
CHUÍ/ BR SYNTATIC MEASURES (186 axial lines)
AXIAL GRAPHS PROCESSED USING MindWalk © Figueiredo, 2002 software
RN graph shows the avenue parallel to the borderline as the most integrated axis
forming the base of a triangle along with BR 471, which encloses the centrality core.
Urban spread is linear, formed by low income housing estates stretching away from the
borderline (N). Urban voids configure barriers (E-W) to pedestrian / vehicular movement,
causing poor permeability parallel to the borderline.
Urbanized perimeter is large, densities are low, urban grid is fragmentary and
discontinuous, following Brazilian urban spread logic of spatial segregation: high depth
land parcels connecting directly to the most integrated axis, fishbone style.
RR graph reproduces Rn logic, except for the incorporation of the longest perpendicular
axis which leads to most of low income housing estates built along it.
CHUÍ / BR CONFIGURATION ANALYZIS
CHOICE MAP highlights RN & RR: the only route connecting the whole urban system,
vital to vehicular / foreigners circulation is parallel to the borderline.
System’s logic lay on the interface with Uruguay. Therefore, the city first expansion dealt
with the improvement of interface between towns, enhancing linear centrality.
SYNERGY is high, therefore, equivalence between local / global integration: the system
gives no orientation clues on the micro level or is so small that scales are indistinct.
INTEGIBILITY is low, coherent with Brazilian patterns: a stranger has to relay on only
one axis access all the other parts of the system.
CENTRALITY is linear, strong along the border line, coherent to the fact that Chuí / BR
commerce targets Uruguayan public (wholesalers that supply Montevideo and regional
shops). The streets perpendicular to the borderline and connecting directly to BR 471
and to Chuy / UY centre also capture centrality close to the borderline.
Mixed uses are ordinary in the centre (shops / dwellings share one single land plot).
The Eastern periphery, enclosed by the roads linking Brazilian customs office to the
Uruguayan one (BR 471-Ruta 09) and leading to the shore (RS696) where hotels, petrol
stations and warehouses are located, has an insipient centrality.
CHUY / UY SYNTATIC MEASURES (220 axial lines)
AXIAL GRAPHS PROCESSED USING MindWalk © Figueiredo, 2002 software
The system is slightly bigger than that of Chuí / BR, but more compact.
RN graph is quite uniform and the average integration found for the orthogonal grid is
lower than that of Chuí / BR. The diagonal cutting the whole urban grid and connecting
Rutas 19 AND 9 to BR 471 captures integration. This street canalizes heavy load traffic
from inner Uruguay to international roads and functions as peripheral limit to the city
centre. Commerce doesn’t profit from its locational advantages.
SW periphery shows lower integration values due to “slum like” land parceling.
The axis parallel to the borderline has different integration status than its Brazilian
counterpart, but houses most of duty free shops. The more integrated axis perpendicular
to the borderline connects both cities cores and customs offices.
RR GRAPH depicts a more local integrated axis on the SW periphery denouncing the
local importance of the “slum informal grid” connection to the urban fabric.
CHUY/ UY CONFIGURATION ANALYZIS
FAST CHOICE depicts the diagonal running E-W and cutting the urban grid in two
halves as the town’s most important street. It limits distinct morphological zones, where
the orthogonal grid changes proportions for newest urban expansions rectangular
blocks. Mean Depth is kept low thanks to the diagonal axis.
SYNERGY is high and main distinctions on Rn RR are constituted by few lines
perpendicular to the borderline that form the city core. A more integrated axis on the SW
periphery denounces the connection to the “slum informal grid” were a big land parcel
was subdivided by dwellers according to their own needs.
INTEGIBILITY is higher than that of CHUÍ/BR, but lower than the average found for
other Latin American samples (MEDEIROS & HOLANDA, 2007) due to the patchwork of
mismatching orthogonal grids that form its urban fabric. The diagonal axis is important to
identify the city parts and its shallowness allow orientation at global and local scales.
CENTRALITY is, however, not linear, spreading on the Northern part of the orthogonal
grid, especially along avenida Brazil between Artigas and Numancia and on the blocks
surrounding its main square where hotels, restaurants and duty free shops are located.
It contradicts tendencies depicted from Rn graph and indicates that to understand the
city centrality is necessary to weight the effects of CHUÍ – BR Integration patterns.
CONURBATION
CHUÍ / BR CHUY / UY
RN & RR graphs make clear that centrality spreads along the borderline, a
shared linear centre for both towns, its immediate adjacencies contained by road
accesses on both sides, crowned by customs outposts.
The conurbation displays similar global and local integration measures on most
axes what reinforce centralities on both local and global levels.
Phenomena seems to be a consequence of the system small size coupled with
the symbiotic effects of the conurbation itself. The diagonal highest integration (Rn, /
RR) implies that the connection between Uruguayan and Brazilian countryside is
extremely important for regional economy.
THE CHUÍ / BR - CHUY / UY CONURBATION
Comparative Space Syntax measures / correlations
(data: by the author,)
No Axial
Lines
Rn max
Rn min
RR max
RR min
Integibility
Synergy
Mean
Depth
CHUÍ / BR
182
3,04
0,56
3,4
0,33
0,29
0,91
3,44
CHUY / UY
220
3,21
0,33
4,47
0,33
0,58
0,95
3,59
CONURBATION 398
2,38
0,64
4,20
0,33
0,58
0,94
4,28
SINERGY high level confirms the coherence between global and local integration
and basically reproduces the parameters for both cities.
INTEGIBILITY improved to Latin American patterns through systems conurbation.
MEAN DEPTH is lower than Brazilian sample average (MEDEIROS & HOLANDA, 2007).
CENTRALITY relay on the inteface between cities, along the borderline
Instead of a conurbation, the system resembles a single city, its configuration
laying beyond complementarity, closer to symbiosis.
Separately, each spatial configuration seems illogical and difficult to grasp:
both cities share centrality and spatial segregation patterns are less distinctive.
The idea of twin-cities / conurbation does not apply here. Instead, that
of one single city spreading over two national territories is more suitable.
SANTANA DO LIVRAMENTO / BR – RIVERA / UY CONURBATION
images: Google Earth
Settlement
Foudation
Municipality
Department
SANTANA DO
LIVRAMENTO
1857
BR
RIVERA
UY
1865
top down: © Ailton Fabian Ribeiro / © Amilcar Mello (1950) / © Fabian Ribeiro
Geographical
area
Distance to
Montevideo
Distance
to Porto
Alegre
Acessibility
Urban
population
Urban area
Santana do SO
Livramento
502Km
501Km
BR 290
BR158
74910
inhab
9,370
sqKm
Rivera
502Km
501Km
Ruta 5
101504
inhab
6,350
sqKm
NO
GENERAL DATA ON RIVERA (UY) / STA LIVRAMENTO (BR)
•
Rivera is the 4th Uruguayan city in size and income and
situation improves since the creation of duty free zones in
all Uruguayan borderline towns (1986);
•
Santana do Livramento, an important benefice industry
center until 1960, is recently overcoming the decay it has
been suffering since then;
•
Until 2000, commercial activity was stronger on the
Brazilian side of the border, with several shops and
wholesalers supplying Uruguayan market. Nowadays, its
commercial activity and services are complementary to
Rivera free shop zone, linked to Tourism Industry;
•
Regional development remains uneven and tied to
economical shifts, characteristic to frontier zone dynamics.
SANTANA DO LIVRAMENTO / BR SYNTATIC MEASURES (1128 axial lines)
AXIAL GRAPHS PROCESSED USING MindWalk © Figueiredo, 2002 software
RN graph displays a quilt of grid patterns separated by large voids and connected by
a deformed wheel macro system of more integrated lines (BR 290, BR158 roads),
which encloses the old core orthogonal grid and links insulated residential enclaves.
The city core most integrated axis is perpendicular to the borderline, linking both
Livramento and Rivera symbolic city centers and is one of the busiest commercial street.
RR graph depicts the grid uneven integration distribution. The “X” shape axes enclosing
the borderline surroundings are more integrated locally. The area housed slaughter
plants that provided most job offers until 1960. Its shallowness and linkage to the
borderline allowed Uruguayans and Brazilians even accessibility to workplaces.
SANTANA DO LIVRAMENTO / BR CONFIGURATION ANALYZIS
FAST CHOICE displays the importance of ring roads system to regional and
international transit inside and through the city, concentrating accessibility and also
the road system ringness from where tree like residential suburbia spread.
SYNERGY & INTEGIBILITY are low, while Mean Depht is high as a typical Brazilian
(MEDEIROS & HOLANDA, 2007) city might be, displaying: economy of lines, patchwork
resemblance grid. Configuration reproduces the uneven Brazilian social and
economical structure: subject to property development speculation logic which forces
the increase of urbanized perimeter with low density rates (BRAGA AND RIGATTI, 2009).
CENTRALITY Movement equity along the low hierarchy / control city core allows
fuzzy centrality and even co presence of locals and tourists. Social investments target
segregation and urban spread patterns deconstruct the once accessible (inclusive to
diversified co presence) orthogonal grid structure.
The emergent hierarchy is lead by axes that capture movement in and out of the city,
favoring new centralities intrinsically linked to vehicular transportation and the
suburbia is discontinuous and clustered into up and low market neighborhoods.
The urban structure reproduces complexity, fragmentation and clustering that reflect
the weaknesses of national city governance parameters, either subject to political
struggles, market laws or discontinuity of urban planning policies.
RIVERA / UY SYNTATIC MEASURES (742 axial lines)
AXIAL GRAPHS PROCESSED USING MindWalk © Figueiredo, 2002 software
The system is smaller and more compact than Santana do Livramento / BR, covering a
continuous area through longer axial lines. It spreads by the extension of its longer lines
parallel to the border, keeping the orthogonal grid pattern despite local topography.
RN graph RR graphs display similar measures, therefore accessibility is nonhierarchical, the configuration is shallow and permeability is high on local and global
scales, what characterizes the orthogonal grid dominating the spatial system. Co
presence between locals and strangers (HILLIER & HANSON, 1984) and indistinctive
locational patterns of land use are consequent to the configuration non-hierarchical
character (FIGUEIREDO & AMORIM, 2007) what allows fuzzy centrality along the urban area.
RN and RR distinctions are credited to the system longer lines that connect the urban
core to the road network and its new suburbs.
RIVERA / UY CONFIGURATION ANALYZIS
FAST CHOICE highlights a centrality hierarchy given by the system’s cross-shaped
longer axes: one perpendicular to the borderline (symbolic uses, duty free shops), the
other parallel to the borderline provides main access to newer and peripheral housing
estates and is a local centrality . It also highlights the most important international road
connection linking Livramento “dry port” to Montevideo.
SYNERGY & INTEGIBILITY are high, while the system’s mean depth is lower. These
data are consistent Latin America cities typology (MEDEIROS & HOLANDA, 2007), which is
based on the orthogonal grid.
CENTRALITY is scattered amidst the whole orthogonal grid due to its indistinctive
locational patterns and functions as the city social life core. New peripheries, designed
to absorb migrant rural population answers to a segregative spatial logic, where social
differentiation comes from the opposition rural / urban recent background.
Urban planning focuses mostly in the improvement and qualification of public places
within the orthogonal grid and improvement of periphery infrastructure and governmental
housing expansions. Unlike its Brazilian counterpart, its centre is not emptied or
degraded, land plots and dwellings being more valuable than ever on the city core.
CONURBATION
SANTANA DO LIVRAMENTO/ BR-RIVERA / UY
AXIAL GRAPHS PROCESSED USING MindWalk © Figueiredo, 2002 software
Comparative Space Syntax measures / correlations
(data: by the author, already published in SSS7, Stockholm, 2009)
Santana do
Livramento / BR
Rivera / UY
CONURBATION
No Axial
Lines
1128
Rn max
Rn min
RR max
RR min
Integibility
Synergy
Mean Depth
1,49
0,43
1,66
0,32
0,39
0,62
7,58
742
1889
1,31
1,31
0,47
0,47
3,04
2,15
0,35
0,33
0,64
0,48
0,84
0,67
4,97
7,33
COMPARING BOTH CONURBATIONS
CONURBATIONS
Santana do LIVRAMENTO / BR
RIVERA / UY
CHUí / BR
CHUY / UY
Mean Rn
Subsystem 01
0,78142693
Mean Rn
Subsystem 02
1,04
R - Mean Rn
conurbation
0,850749101
CI - Conurbation
Index
0,930725
Integibility
Synergy
0,48
0,67
1,245928
1,572854
1,426498
1,0121378
0,58
0,94
(data: the authors)
Santana do Livramento / Rivera conurbation CI < 1
The cities systems are better understood separately due to the morphological contrast
between both urban grids.
Rivera has the typical Latin American grid: orthogonal & compact
X
Livramento has the typical Brazilian grid: deep, fragmented and disperse
=
The conurbation performance is weakened due to contamination by Brazilian typology
CAUSES
Differences on urban spread (RIGATTI, 2011) turn the systems interpenetration weak
outside the cores, concentrated on few axes (ring road system);
Blurred city limits are only noticeable in the cores, while on both towns newest parts
morphological and structural changes become clear, even if the systems interpenetrate.
The street system running along the borderline is able to connect the cities without
interpenetration, Rivera concentrating most part of the conurbation integration core.
COMPARING THE CONURBATIONS
CHUÍ / CHUY conurbation CI > 1
The strong Conurbation Index validates the systems codependency:
They must be understood as a whole = a conurbation and a continuous urban fabric
CHUÍ / BR RN and RR measures approach Latin American patterns
X
CHUY / UY
=
CAUSES
The systems interpenetration is high and the conurbation core spreads along both cities.
The axes along the borderline, connecting both settlements grants a large interface
between systems.
The small size of the system and urban dynamics contribute to reinforce the conurbation
character.
Rn and RR higher than Brazilian average ones are also important: despite the fact that
morphological differences between both cities are noticeable, Chuí / BR is closest to the
Latin American samples than to the Brazilian ones, allowing us to think that if we were to
pick up a sample from Mercosul borderline conurbations, certainly Chuy-Chuí would set
typological parameters.
The cities systems are better understood separately due to the morphological contrast
between both urban grids.
Rivera has the typical Latin American grid: orthogonal & compact
X
Livramento has the typical Brazilian grid: deep, fragmented and disperse