The earth and its inhabitants stand in the closest mutual relations, and one element cannot be seen in all its phases without the others" - Carl Ritter (1779-1859)
Mapping is an important activity in landscape architecture. It is a means to generate knowledge for planning and design. This implies a strong forward-looking action from a perspective of sustainable development, so as to guide, harmonise and shape changes, which are brought about by social, economic and environmental processes. Systematic study of urban landscapes is essential and constitutes description, comparison and classification as a basis for knowledge-based planning and design. It utilizes the power of Geographic Information Systems (GIS) to acquire knowledge via modelling, analysis and visual representation.
Landscape architecture uses different forms of knowledge representation as vehicles of thought and communication. You think of spoken and written languages and mathematics and also sketches and graphics. Visual language – drawings, maps and models – plays a vital role in landscape architecture. In landscape research and design the map is a graphical representation of knowledge, a vehicle for thinking and communicating. Visual thinking is a way of generating information by creating, inspecting, and interpreting a visualization of the previously non-visible (seeing the unseen), while visual communication refers to the effective distribution of information in visual form (DiBiasi 1990, cf. Zube et al. 1987). Maps as a product and the process of mapping are both important means for visual thinking and visual communication in order to understand delta landscapes. Maps help us to reflect upon emerging insights, appraise the landscape in its totality, and observe the relationships between the parts and the whole (Nijhuis and Stellingwerff 2011, cf. MacEachren 1995)
‘Engineered Curves’: Cross-reference mapping connects understanding with design thinking (Image courtesy: Mathur and Da Cunha 2001)
Maps have served as tools for handling spatial
data for millennia; they are informative as well as persuasive and are
therefore important means of knowledge acquisition. Maps facilitate a spatial understanding of
things, concepts, conditions, processes or events in the human/natural world (Harley and Woodward 1987). Mapping is an
activity of constructing and communicating spatial knowledge, and the map is a
result of that. The physical creation of maps is the process of map-making.
This can be distinguished from information acquisition and the processing of
spatial data which is termed mapping (Dorling and Fairbairn 1997). Mapping entails
exploration, analysis and synthesis of data and information in a visual way. It
refers to a process, rather than a completed product (Cosgrove 1999). The process of mapping helps us acquire
new or latent information, which is the basis for generating spatial knowledge. Mapping
allows for an understanding on multiple levels because it is not restricted to
a method of digital or analogue visual representation. It is first and foremost
an act of cognition, a human ability to develop mental representations that
allow us to identify patterns and create or impose order (MacEachren 1995). Mapping allows us to ‘digest’
information in a rational and systematic way, which is a personal process influenced
by the choices and judgements made by the interpreter. At the same time, these
findings are made transferable via visual representation, which showcases
relationships, structures and patterns.
Geographic Information Systems (GIS) combine mapping with information technology, thus transferring control of the mapping process from the cartographer to the researcher. GIS offers researchers a platform where they can deal with complex spatial environments, modelling, analysing and representing them. It requires the researcher to understand the mapping process in relation to the possibilities and limitations of datasets. The wide range of possible applications in urban planning and design makes GIS a vital instrument in landscape architecture.
Map dissection, map comparison, and automated map analysis are useful analytical operations. Map dissection is about discovering spatial patterns by selection and reduction, and often serves as the basis for spatial association analysis, which explores the relation between different patterns. Techniques for spatial association analysis are overlay analysis and cross-reference mapping. Overlay analysis is employed to derive relationships by applying thematic overlays to geographic location. Although this technique was already applied by the 19th century landscape architects Warren Manning and Charles Eliot, it was Jacqueline Tyrwhitt, mother of planning, who was the first to describe the overlay technique in an academic setting. “Possible maps should be drawn on transparent paper, so that when completed the maps to the same scale can be ‘sieved’, i.e. placed one on top of another in turn so that their correlations or their absence can be noted. Where relevant these sieve maps should be made bringing out the degrees of correlations noted on certain matters” (Tyrwhitt 1950: 157). Later, this method was further developed for suitability mapping by Ian McHarg and had a major influence on the development of GIS. In mapping urbanized deltas, overlay analysis by means of GIS is used to explore such things as the correlations between environmental conditions and patterns of land-use and human settlements. A recent variation of overlay analysis is cross-reference mapping. Here, location-specific information is superimposed or merged with other layers of information. This ‘suggestive’ cartography offers alternative readings of a landscape and explores certain relationships while integrating thematic maps with statistical information, photographs, diagrams, sections. This type of mapping connects understanding with design thinking and involves a high degree of subjectivity. However, in this work, the emphasis is on understanding and we therefore draw on ‘conventional’ use of maps. Map comparison is about finding similarities and dissimilarities in space, time, and theme between the different urbanized deltas, as well as within the individual delta. Since spatial dynamics and changes over time are hard to express in a static map, different time-slice snapshots need to be mapped in order to delineate the development of a particular delta landscape. These time-slice snapshots can be combined in several ways: via overlay, attributes or in a series. Automated map analysis is employed to explore the available digital datasets, to calculate elevation zones, as well as land-use within different elevation zones, and to summarize quantities such as precipitation or river discharge.
This text was excerpted from: Nijhuis, S & Pouderoijen, MT (2014) ‘Mapping urbanized deltas’, in: Meyer, H & Nijhuis, S (eds.) Urbanized deltas in transition. Amsterdam: Techne Press, 10-22