Leiden
Invisible fortresses
Nilofer Afza Tajuddin Student No. : 4618963 Q1 - AR1U090 R&D Studio: Analysis and Design of Urban - November 2016 Tutors : L. M. Calabrese, Jiaxiu Cai
Contents
01 Introducing Leiden
02 Typomorphological Analysis Evolution of city Land use mapping Patterns of typo-morphologies Expression of form Image of Leiden The (in)visible city
03 Urban Landscape
Urban landscape as a dissecting element Experiencing infrastructural barriers Mapping barriers clusters in phases as agrowth strategy Local patterns and clusters Infrastructure as a barrier
04 Concept of an open city Interacion of public open spaces Boundaries of urban form vs open city Public open spaces in the city Mapping public within clusters Public spaces on various levels The fractal city
05 City as a Complex System
Facors contributing to complexity Different clusters, differing complexities A sea of monotony with occasional pop ups
06 Splintering Urbanism 07 Challenges and Potential
Finding the tape that binds the city together Creating seamless connections
07 Appendix
Demographics area : 23.27 sq. km land : 21.95 sq.km water : 1.32 sq.km poulation : 190,000 inhabitants density : 5,524 / sq. km
Amsterdam
Leiden The Hague Rotterdam
Leiden - an introduction
N206
A44
A4 N11
LEGEND Built form - Historic centre
Built-form of city Highways Arterial Roads
Lalyers of Leiden
Water network Railway
typo-morphological analysis Exploring the expression of the city
prologue The classification of urban form based on its expression was adopted as the concept for the typo-morphological analysis of Leiden. While the various parts of the city could be grouped based on programme and function, it was also observed that each group often has an expression, a style or an image attached to it. Based on these images, the contribution of each group to the overall content of the city was analysed. Concepts such as contexuality of form, specificity and meaning of urban patterns were also addressed. From the initial experiences of the city, observations of the stark transition from the historic core to the outer most development of the city were made. Using tracing techniques, the map of Leiden was drawn as a composition of clusters, each with reflecting a unified image.
1200
1351
By the year 1200, the land on the south-west bank of the confluence of the Rhines had been development. The pattern in this segment had largely been influenced by the two arms of the Rhine and the artificial canal dug around it.
LEGEND Previous built-form New additions of built-form Highways Arterial Roads Local street network Water network Railway
1574
1386
By 1386 irregular development to the south of the 1200 segment takes place. As the fortification pattern has not been established yet, the development pattern takes place in a random manner however still related to the water network.
Later by 1351, the northern portion of the bank is developed, the pattern now reactive to the artificial canal surrounding it.
1600
Subsequent developments take place in 1600 responding to the landscape of the river island.
With the Spanish siege of 1574, the land all around the existing old town is flooded, in a moat-for tification pattern that is recognisable even today. Hence the boundary of the city centre is set, however its pattern is not.
1610
1644
1659
1842
>1856
With the introduction of the Railway system, a new layer of infrastructure is added to the system of the city.
The development by 1610 takes place north of the existing city, and its pattern also responds to its immediate landscape.
The development by 1659 (Re-developed in the late 1950s due to poverty in the region and decline of textile industry)
From 1856 onwards, development outisde of the fortifications take place and in these new extensions of the city, the various layers of urban landscapes play a vital role in shaping the structure of each segment of the city.
Evolution of the city
>1900s
Subsequent developments take place in a cluster-like development, each cluster carved out by either the water or road network surrounding it. The nature of development of Leiden as an agglomeration is prominent in this cluster based growth as each cluster responds to its immediate urban landscape that it is flanked by.
2016
LEGEND Previous built-form New additions of built-form Highways Arterial Roads Local street network Water network Railway 0
20 km
40 km
60 km
LEGEND Mixed use
Primarily residential Commercial
Institutional Highways Arterial Roads Water network Railway
Land-use mapping
Timeline
Historic core
Commercial patterns
Residential Patterns
1200-1900
1900-1950
1950-2000
2000-2016
Patterns of various typo-morphologies
1
2
Definitive clusters based on their organisational network are identified within the extent of the city. Using tracing techniques, clusters based on the imageability are drawn.
3
4
5
5
6
Bioscience park
City centre
1
4
6 3
2
2
Expression of the various morphologies
1
1
2
2
Image of ‘Leiden’
Contributions to perception
This model illustrates how the core of what defines Leiden is expressed in terms of opaque material whereas the newer developments, portrayed in flexi-glass seem more generic and misplaced in the context, which is Leiden. Despite multiple additions to the city, it is images from the centre or the old city that we associate Leiden with.
The clear contrast between the generic and the specific parts of the city raise questions of the contextuality of form and the value that these clusters add to the city of Leiden on the whole. The inner core has significance in terms of crystallising time and events through the course of the history and hence is often recognised as the ‘image’ of Leiden rather than the rest of the city’s clusters. The Bio-science park on the other hand, through its multitudes of programmes and contribution to the commercial and institutional sector of the city, defines its place and meaning in the context of Leiden.
LEGEND City centre Generic segments of the city
The (in)visible city
urban landscape Tracing the influences on the character of the city
prologue In this section, the impact of the urban landscape elements namely water structure and infrastructure elements on the morphology of the city were analysed. The historic evolution of the city was traced with respect to the urban landscape. In the case of Leiden, the water structure and road network played an important role in shaping the city that we see today. The degree of the influence of each element is analysed with respect to the existing context of Leiden.
1600
1200
1350
1850
1550 LEGEND Land form of Leiden Highways Arterial Roads Water network Railway
Urban landscape as dissecting elements
1900
LEGEND Land form of Leiden Highways Arterial Roads Water network Railway
2016
Urban landscape as dissecting elements
Route of Field visit
Experiencing Infrastructural Barriers
Mapping Barriers Depending on the nature of the barriers, the strength of the same was marked across the city. Stronger the barrier, strong the divide.
Types of boundaries mapped
LEGEND Extent of Leiden City centre Strongest boundaries of infrastrcture
Perception of boundaries
clusters in phases as a growth strategy
LEGEND Growth until late 1800s
Growth from early 1900s-1950s Growth from 1950-late 1900s
Growth from 2000 onwards 0
20 km
40 km
60 km
Highways Arterial Roads Water network Railway
Local patterns defined by bounding landscape
LEGEND Growth until late 1800s
Growth from early 1900s-1950s Growth from 1950-late 1900s
Growth from 2000 onwards
0
20 km
40 km
60 km
Local Patterns influenced by Urban Landscape Highways Arterial Roads Water network Railway
Infrastructure as a barrier Since the initial growth of the city in 1200, the city has in fact grown in clusters, defined by the landscape of the region. The water structure in many cases has been the defining element in how the land was carved out of the city’s fabric. While phasing is a common approach to the development of cities, in the case of Leiden, this phasing or clustering with respect to time has taken place with the urban landscape as its key influence.
With respect to the historic evolution of the city, the growth and structure of the city was largely influenced by the water structure and the major traffic system that subsequently emerged. Treating these as the urban landscape of the city, the clusters are now refined based on both typomorphological and landscape analysis. The urban pattern of each cluster follows the structure of the bounding landscape elements.
This model shows the multiple urban landscape elements (blue and black strips) that dissect the city into several islands. Moreover, the inner configuration (white strips) of each island tends to follow the structure of its immediate, bounding landscape.
* A cluster maybe defined as a group of elements bearing similar characteristics grouped together. The factors that influence these differences with respect to the urban fabric may be influenced by the location, expression of form, language and style, morphological patterns and other patterns such as growth, landscape. When clusters are superimposed with the aspect of time, the concept of phasing emerges. Phasing is common in most cities as most cities are developed in segments or parts.
Urban landscape as a barrier
open city barriers vs open-ness
prologue Using Nolli and Bacon Mapping Techniques, various public and private spaces in selective regions of Leiden are mapped. It is noticed that the distribution of the public varies across different parts of the city. Based on these configurations, the porosity of each cluster of the city is mapped. Patterns based on the distribution of the public spaces and porosity are derived.
How do these clusters relate to the open city concept?
Interaction of the public open spaces
Public-ness of the city
LEGEND Public - Open spaces Influence Barrier - Infrastructure
LEGEND Most Public zone
Less Public zone
Least Public zone
Zero Public zone
Barrier - Infrastructure
Resultant porosity of the city
LEGEND Punctures Strong urban form
Boundaries of urban form vs the open city
LEGEND Public - Open spaces
Public open spaces across the city
The planned - Cauli-flower like residential development
The planned residential development - Post war Housing
Public (White) vs Private (Hatched) Public (White) vs Private (Hatched)
Varied public spaces
Selective clusters are chosen and the various public spaces are mapped. In most cases, it is observed that there exists a central public core in every cluster and the public realm further disintegrates into privatized public zones which cater to immediate surroundings. Based on these smaller privatized public spaces, clusters within cluster can be identified.
Varied public spaces
Mapping the public within various clusters
The City centre
Open spaces
Public (White) vs Private (Hatched)
Public (White) vs Private (Hatched)
The Bio-science Park
The bio-science park and city centre however function differently, with most of their spaces either exclusively public or public on the whole. The former is largely composed of commercial, high-rise buildings of economic value and hence caters to that section of the population. The city centre on the other hand, composed of a large variety of function aimed at both, the tourists and the locals, acts as the communication core to the entire city.
Varied public spaces
Mapping the public within various clusters
LEGEND Cluster boundaries Open spaces Public accessible
0
20 km
40 km
60 km
Public spaces on a city level
LEGEND Cluster boundaries Open spaces Public accessible
0
20 km
40 km
60 km
Public spaces on a cluster level
LEGEND Cluster boundaries Open spaces Public accessible
Public spaces on a neighbourhood level
This model illustrates the distribution of public spaces across the city. Aiming to capture the hierarchy of these spaces, the centre is depicted in white as the most public. While the bioscience park functions as an exclusive public zone, the surrounding residential developments are privatized clusters. However within these private zones, there exists the most public (in most cases, central) core and a further distribution of smaller spaces catering to the immediate residents.
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The inner city may be considered most public based on the variety of programmes and points of interests that engage people from not just in and around the city but also the inflow of tourists. The bioscience park functions as an exclusive public space, with programmes that cater to specific sections of the people like those from the institutional and commercial sector. The residential clusters however are privatised to the residents and within these clusters, there exists a hierarchy of public spaces ranging from a large (in most cases) centrally located most-public space to small public spaces that are mainly intended for the immediate residences located along its boundary.
The fractal city
city as a complex system Complexity and the control field
“
We need to understand what made built environments bloom and adapt to daily life for thousands of years. I look at the built environment as the result of patterns of human control. Control of physical things is defined as the ability to change them, and control of space the ability to refuse entrance to it. Control, therefore, equals the ability to intervene, which makes the observation of change and movement the key to our study of environment. This approach is not new. Observation of transformations is the most common way to study nature. Patterns of form behaviour reveal an inner structure. We need not know the intentions and meanings of the agents who exercises control, but we must look at what happens to the built environment as a result of their actions.
prologue
In terms of control, inhabitation means both the control of a space and the control of things in it. This combination of control I will call a ‘control field’ or just ‘field’. Thus ‘field control’ is the kind of control exercised by the inhabitant party over its space and the things in it. Field control causes the environmental complexity that we admire in historic built environments. In its smaller scale manifestations it represents the ‘bottom up’ process that is often considered desirable for environmental quality. It produces a complexity that is natural and spontaneous and, by definition, responds to inhabitant values and needs. No two individuals ever act in exactly the same way. Hence the more field control is distributed among many inhabitant parties, the greater the variation in form that results, and the more we will experience a built environment as complex. Also, the more these variations are thematically similar in their individual differences the more environmental complexity strikes us as the result of a coherent culture of inhabitation.
”
- Chapter 4 ; Cultivating Complexity: The Need for a Shift in Cognition - N. John Habraken
The city is composed of several layers belonging to the physical and social environment. Each layer contributes to its complexity of the system that is the city. Based on control fields (the degree of control that an individual exerts over the physical environment) this complexity varies across different sections of the city. In the case of a residential neighbourhood that is entirely planned up to the exterior shell of a residence, the occupant has control only over the interiors and hence that may be the only unique or unpredictable factor in the entire neighbourhood. This makes two levels of control: A uniform layer controlled by the designer and the unstable layer controlled by the occupant. In the absence of the latter, the complexity maybe considered negligent due to the monotonous repetition throughout the entire area. Complexity hence in this case is defined by the degree of unpredictability of the physical environment by the social components. Based on this concept of complexity based on control fields, the city is mapped.
Programme specific vs Flexible urban development
Controlled vs Uncontrolled urban development
Dictated by a third party vs personalised urban forms
Planned vs Unplanned urban development
In the case of the historic centre which has developed over time, each new addition adds complexity as the variety and freedom of the occupant in defining his physical environment (outer shell, expression of form, interior) is much larger than that of a planned neighbourhood. Based on this analogy, the layers that add complexity to the urban fabric of Leiden may be identified. It is the juxtaposition of these layers that make one section of the city more complex than the other. • Nature of Development – Controlled vs uncontrolled • Network of urban form – Planned vs Unplanned • Imageability – Controlled(Repetition) vs Uncontrolled(Personalised/Variety) • Time – Developed (In one phase) vs Formed (Takes into account capturing history & culture, adaptability, change over time) • Adaptability – Built to serve (Programme Specific) vs Flexibility (Adaptive reuse of old structures) • Enclosed spaces - Designed by a third-party vs Personalised by inhabitant
Repitition of the shell and subsequent imageability vs
Urban development at a given period of time vs Urban development over time Variety and diversity in image
Factors contributing to complexity
Different clusters, differing complexities Using these layers are guides, clusters of varying complexity can be identified within the city of Leiden. Due to the strong history that ties it together, the city centre maybe be considered most complex owing to its unpredictability and strong factor of time. In the case of the Bioscience Park, although the entire region is controlled by nature of its overall purpose, each structure is controlled by different authorities and hence the control and complexity is more diverse. In the case of the residential settlements outside of the historic centre, there are two types that can be identified. In the first type, the settlement was formed over time, and the absence of a planning strategy is evident in its pattern. This type also consists of those which do not have a predetermined facade or external elevation attached to it and hence differ in form and as well as content. In the second type, the residential cluster is developed at a fixed period of time by an external authority and has a predetermined image associated with it. The freedom of the occupant exists only in the realm of the interiors. Most complex
Multiple hierarchy of control field
Two level hierarchy
Bio-science park
The level of unpredictability plays an important role in not just defining the complexity but also in terms of the imageability of the city on the whole. When the physical shell is clearly defined, the exterior image often tends to be a continuous repetition of a single image. However, the more flexible this shell, the more diverse the image.
The various juxtapositions of the layers that define complexity of a cluster are shown in this model. Based on the degree of control that an individual exerts on a given area, the single brown leaves are used as tools to depict that of least complexity. With the use of the green leaf strips, another layer is added to certain zones, implying a higher level of complexity. The black feather depicting the bioscience park implies a complexity of a different kind, of a zone which is largely composed of designed structures with a commercial value. While the city centre retains its value as the most complex, the symbolic ‘historic’ quotient ties the entire zone together.
A sea of monotony with occasional pop-ups
Splintering urbanism * Fragmentation* as a threat to social and physical cohesion
A city of invisible fortresses
* A term coined by geographers Steven Graham and Simon Marvin to refer to the ways in which infrastructures, including information and communication technologies, can fragment the experience of the city. * As an operational term, urban fragmentation is used by scientists to describe the phenomenon of increasingly differentiated societal and spatial polarization within cities, which seems yet difficult to grasp or to calculate in its further dimensions and effects. - The struggle to belong Dealing with diversity in 21st century urban settings. - Veronika Deffner & Johanna Hoerning
Is Leiden a whole of its parts? In terms of the city being an agglomeration, the character of the city can be indeed defined by how fragmented the city is. Unlike few other agglomerations that were formed over time, Leiden was projected as an agglomeration city ever since the initial growth of the city outside of the city centre, hence making each island or isolated cluster even more prominent. This cluster tends to be, in most cases, self sufficient hence creating multiple neighbourhoods that do not interact with each other. The city centre which is treated as a communication core, now functions purely as a convergence point of the road network connecting these islands.
Challenges and Potential Finding the tape that binds the city together
It is the detachment of different parts and the establishment of internal boundaries that break with the city (planned and thought) as an entity and lead to “juxtapositions of very limited and confined, socially specialized spaces� (Navez-Bouchanine 2002b, 57, translation JH). From another angle, fragmentation of urban form is understood as a disorderly process of development that leads to the splintering of urban space and makes the city a mosaic without a distinguishable centrality. So, there seems to be an almost consensual view that fragmentation has something to do with disordering or undoing of the planned city, leading to chaotic or mosaic structures. - The struggle to belong - Dealing with diversity in 21st century urban settings. - Veronika Deffner & Johanna Hoerning
The Disconnect between the different clusters has caused a severe fragmentation of the city into self contained and isolated islands. The city centre and bioscience park may be considered the only existing sections of the city that engage more than just their immediate surroundings. This fragmentation and repetition of clustered developments may have been in response to the population explosion but however do not contribute to the integration of the city as a whole. There is a need to address the specificity of each development and to question how much it contributes to the complex system of the city. In response to this, there is a need to introduce design and planning strategies that encourage interaction and overlapping of the clusters.
Creating seamless connections
Main axis of the green corridor
Section of green corridor through roadways
Section of green corridor through waterways
In a city where the landscape is the main barrier, strategies that break these invisible fortifications can be adopted in order to create continuous, seamless connectors throughout the city.
Main axis Connections through arterial roadways Public core
By creating a pattern using the open spaces in the city, strong connections are made such that the public space multiplies throughout the city. This pattern is superimposed over the existing infrastructure and a major axis is established from the North to South. Subsidiary axes are created and all these eventually plug into the main axis. This connector is further elaborated as the green corridor that runs throughout the city. This connection can further be strengthened by adding a programmatic value to the main axis such that the axis becomes more meaningful.
Public core
One of the main impacts of this intervention is that it shifts attention from the mono-centric core and creates an alternative axis to experience the city. The E-W Axis is strong due to the river system, and hence by creating the N-S green corridor, the city can be stitched together as a whole.
Park connector concepts
Appendix
What is a city portrait
“
A portrait offers insight into the many complexities that make up a city
Excursion Sept 2016 During the excursion, one of the key observations from my perspective was of how the landscape changed based on the the extent of the city and the green fields separating them. The cities that we passed through always seemed to be clearly defined within boundaries and the transition from the inner parts of the city into the green landscape saw extreme contrasts. The cities that I’ve visited earlier in India seemed to phase out into the countryside and traces of the city in terms of the built form were visible even after the exit from its boundary. However in the Netherlands, cities seem to follow a definitive pattern and demarcation hence making the green areas and the flat, green landscape even more prominent.
The sketches show this transition between the various cities that we visited, highlighting this clearly visible transition between the built and the un-built. The character of the cities is shown through lines, which differ in length and density. I believe that in terms of Urban Planning, each city seems to be confined to a given area, hence preserving the green landscapes. The cities do not wander into the countryside and vice versa.
Also, in term of the relationship between the built and the un-built in case of the Beisbosch, the structure blended into the landscape and hence was in harmony with the context. In term of the IJburg area, the canals and waterfront development seemed to blend together to form a picturesque view of the new extension of Amsterdam. The planned developments, the docks and all the canals complimented each other.
The Amsterdam eye The westlands
IJburg Biesbosch