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Foot Soldiers of GeoDesign

Joerg REKITTKE, Philip PAAR and Yazid NINSALAM

1 Introduction

Considering the growing variety of electronic tools being deployed by geo-oriented landscape designers and researchers in fieldwork operations, we are able to distinguish two main groups of users. The first group we refer to as ‘aviators’. Namely, colleagues who profit directly from satellite data as well as all sorts of sophisticated aerial imagery. Aviators’ GeoDesign fieldwork is fueled by an approaching armada of flying devices like drones and all sorts of helicopters, carrying high-capacity cameras and scanners that deliver image data as well as geo data for precise 2D imagery, mapping, and 3D modeling.

The second group we refer to as ‘foot soldiers’. Being a foot soldier – of GeoDesign (FLAXMAN 2010) – does not mean that the chosen equipment is not related to the mother technology of the aviators – satellites, radio, and data networks – rather, it has to be light, portable and inconspicuous. An ideal stage of operation, for the GeoDesign foot soldiers, is the informal city, amidst unclear and labyrinthine urban grounds, street sites or waterscapes. Their mission is to provide for terrain data and details that cannot be gathered by the aviators (Fig. 1). Even with all the available remote sensing technology, in order to build complete and highly detailed models of complex terrain and urban territory, the direct contact to ground and detail will remain indispensable.

Fig. 1: More than 200 people room under this vast street bridge – only detectable by the foot soldier after climbing down the ladder (Photo: Rekittke)

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Compared to the sophisticated machines and efficient methods in remote sensing, the craft of the GeoDesign foot soldier appears to be more intricate and laborious – but it can deliver unique results. In this paper, we pick such a result as the central theme. We will describe a method of on-site data and image gathering, which allows the processing of highly detailed and widely correct 3D models of labyrinthine spaces. The necessary equipment used is comparatively low cost; the software and online services, free.

2 Methodological and Geographical Context

2.1 Low-key, low-cost

This paper describes the last of a series of three fieldwork studies in the context of the research project “Grassroots GIS”, financed by the School of Design and Environment, Department of Architecture, National University of Singapore (NUS). The method at hand is the sequel to fieldtrips and works by the authors in 2010, 2011 and 2012, published within the framework of the Digital Landscape Architecture conferences (REKITTKE & PAAR 2010, REKITTKE & PAAR 2011). The research is conducted in combination with special landscape design studios in the context of the NUS Master of Landscape Architecture programme. In 2012, we embedded our NUS based research into an interdisciplinary research program entitled Future Cities Laboratory (FCL), under the aegis of the Singapore-ETH Centre for Global Environmental Sustainability (SEC). The Centre serves as an intellectual platform for research, scholarship, entrepreneurship, and postgraduate/postdoctoral training, aiming at the provision of innovative scientific methods, instruments, and product research. We operate in the research module “Landscape Ecology” (GIROT & REKITTKE 2011).

Grassroots GIS relies on the bottom-up principle and integrates 2D and 3D geospatial data and tools for the purpose of landscape design activities. We developed a toolbox and user-generated geospatial content process that supports mapping, storing, staging of interactive design, disseminating, and generating interactive visualisations of landscape architectural interventions in the context of urban informal settlements. Grassroots GIS implies easy and free access to applied tools, geodata, and georeferenced design data. This premise calls for attention to open-source, open standard and cost-free or low-cost tools and data storage possibilities (REKITTKE & PAAR 2010).

2.2 Jakarta and the Ciliwung River

The outline of the FCL research module “Landscape Ecology” has been published recently. The article pictures the extreme condition of Jakarta and the rivers which cross the city (GIROT & REKITTKE 2011): “The urban catchment of Greater Jakarta, this metropolitan Moloch, has reached a population of about 28 million today and is expected to reach 35 million by the year 2020. But the exact figures are irrelevant; one senses overpopulation and its consequences everywhere one looks. Jakarta is located in a delta plain where 13 rivers merge into the Java Sea; the Ciliwung River is only one of them. The city is quite literally a sinking ship, as some parts of Jakarta sag almost 25 centimetres per year. This extreme subsidence rate is due to abusive ground water extraction, with the ground giving-in to the city’s sheer weight. Jakarta is also prone to cataclysmic flooding, which has

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become a major annual problem for the city. The worst flood in the history of the Indonesian capital happened in February 2007: it covered almost 60 percent of the total urban area. In Kampung Melayu, one of our areas of study, the water level of the Ciliwung River reached a height of more than 10 meters over the valley floor.”

Fig. 2: Ciliwung River in Jakarta – a natural watercourse in the shape of an open-air sewer (Photo: Rekittke)

Scientific spot tests confirm that almost all residents of informal settlements along the riverbanks discharge all their waste and sewage directly into the rivers (TEXIER, 2008). These people and their culture of pollution are not the only reason for the status of the rivers – the whole of Jakarta distinguishes itself by a total lack of a sewage system citywide. The environmental consequences of negligence and mismanagement are enormous (Cochrane et al., 2009), not only for the realm of the Ciliwung River. An incredible amount of artificial sedimentation – plastic waste – makes up its riverbed in central Jakarta (Fig. 2). Are we able to generate any impetus towards the improvement of this worst-case situation on the ground of the Jakarta Megacity?

2.3 Fieldwork mission

Via our research we are trying to contribute to a potentially positive answer of this profound question. Any realistic landscape design intervention along the Ciliwung River will be intrinsically tied to the relief along the river. The difference between the harsh, comparatively “lank” slum layer along the immediate riverbanks, and the quasi-ideal, dense mixed-use urban idyll of the kampung – the Indonesian urban village – with occasionally

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high quality houses, is widely defined by altitude differences. The simple formula “lower location = bad housing / higher location = better housing” cannot be generalised but applies to most of the area along the river (Fig. 3). Analysis and understanding of the terrain logic necessitates precise cross sections and three-dimensional models, which – typical in the complexity of narrow informal worlds – have to be acquired in the cumbersome foot soldier way. One way to build such models is based on the handmade photo-to-point-cloud technique that we approach in this paper.

Fig. 3: Same kampung – different altitude (Kampung Melayu, Jakarta): Slum layer down at the riverbank, high-quality housing up on the hill (Photos: Rekittke)

Being regularly flooded or comfortably living with dry feet becomes a matter of decimetres or even centimetres. Precise measurements in the field sometimes shape up as being problematic, because in the informally founded urban environment precision is a widely disregarded concept. Hence precise and measurable models of the site can contribute to additional clarity concerning profound design decisions.

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3 3D Models of Unseen Spaces

3.1 Photo-to-point cloud

Lacking an expensive and chunky 3D terrain scanner, the common handheld digital camera serves as quick and easy imaging device for the foot soldier of GeoDesign. Instead, we are experimenting with consumer based photogrammetric 3D reconstruction software. The free software and online service 123D Catch (formerly Project Photofly) from Autodesk Labs Technology (AUTODESK 2012) allows for the creation of 3D models from digital photo-graphs, usable for accurate measurements. The software and related workflow has primarily been developed and optimised for single object photography and corresponding modeling (Fig. 4), rather than for the capture and modeling of complex spatial entities. For our landscape architectural purposes, creative experimentation as well as unprejudiced trial and error can lead to sophisticated results.

Fig. 4: Object centred photo ‘catching’ and 3D modeling: ‘Slum W.C.’ located on a floating bamboo raft on Ciliwung River. Recorded through circular photography from multiple viewpoints (Photo: Rekittke; 123D Catch sample: Ninsalam).

The standard workflow for 123D Catch models calls for the following steps: 1) Taking of multiple digital photos with any standard digital point-and-shoot camera; 2) Upload of photos in an image file format (jpg) via 123D Catch software – to a cloud server for stitching and processing. The software automatically downloads the results in a Photo Scene data file format (3dp). The cloud server mesh engine processes a high quality 3D model from the collection of overlapping photos. Provided that the system is fed with an extensive, well-taken set of photos, the resulting model will be spatially and dimensionally accurate. Via manual stitching – adding or removal of photos that had not automatically been included – the results can be adjusted; 3) Saving of the project as a video animation,

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or export of the underlying wire frame (model) into standard 3D formats (obj, dwg) for further editing in various 3D programmes.

3.2 From object to space

We are systematically trying to push the limits of 123D Catch. Clearly laid out objects are easy to catch and the resulting models are good. It is evident that with a bigger and more complex spatial situation, the limitations of the software become clearer. It comes as no surprise that the 3D models of intricate spaces feature holes, due to the fact that sometimes even the most athletic foot soldier is not able to physically capture all necessary images from certain vantage points. When it lacks source data to fill in all regions of the generated 3D model, gaps are inevitable. Yet, there are several ways to optimise the results of works on larger complex spaces.

Shoebox method Freestanding objects allow the photographer to revolve around them and take pictures from evenly distributed multiple viewpoints. For the catchment of an entire space this principle has to be inverted. The typical empty middle of the space has to be regarded as a virtual, see-through object that is scanned in a shoebox shaped manner (Fig. 5).

Fig. 5: Shoebox image capture method along a street at Manggarai Selatan, Jakarta. The small white camera icons indicate the location from which photographs were taken (Sample: Ninsalam).

Semi-circle method Where we conduct our foot soldier handcraft, many streets especially alleys are too narrow for the application of the shoebox image capture method. In these cases we experiment with semi-circular camera movements around the alley mouth, to capture as many overlapping image instances as possible (Fig. 6). Generally, we have to try to achieve enough visual redundancy for satisfactory post-processing results. The described field photography

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method does not allow us to control the adequateness of the image capturing on site – only with Internet access, e.g. in the hotel or a nearby 7-Eleven store, we can examine our results. This bears the risk of coming home with fragmentary material.

Fig. 6: Narrow alley situation. A semi-circular path was taken by the photographer to capture the space (Sample: Ninsalam).

We generate 3D working models for the purposes of measuring, design decision-making and participatory planning. Perfection and aesthetics of the models are subordinate. One very useful feature of 123D Catch, which literally bridges the gaps in the generated spatial models, is the ability to fade in referenced original 2D images as backdrop to the 3D model, by selecting the respective images in the image bar of the programme window. This 3D/2D mixed depiction provides a better comprehensibility and reading of the model with regard to its spatial context (Fig. 7). This feature can also serve as an antetype for further experimentation with mixed media techniques of working models. Grassroots GIS and the foot soldier pattern of thought call for the exploration of all thinkable ways in uncommon terrain and city modeling.

Portable scale artifice After having generated a 123D Catch model, it is possible to do accurate measurements of any object in the 123D Catch editor scene. To extract reliable data, at least one reference dimension in the model must be known.

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Fig. 7: Fading in of 2D images as backdrop in the 3D model, by selecting single images in the image bar of the programme window (Sample: Ninsalam)

In order to enhance the accuracy of the measurements we integrated a portable scale into our field photographs. By doing so, the margin of error – caused by optical distortion, stitching aberration, finite resolution – can be reduced. The respective portable scale can be anything found in the field. More technical looking professional scales can easily become a reason for distrust in informal city neighbourhoods, where landownership and right of utilisation are often not readily settled. Supplementary measurements were recorded through handheld GPS devices with in-built altimeters (Garmin) and outdoor laser distance meters (Leica). Compared to the erratic readings of the altimeter from the barometric pressure dependent devices, the well-measured brick is a high-precision artifice (Fig. 8).

Fig. 8: Left: Measuring a brick before positioning it as a portable scale in the field. Right: Supplementary measurements with a Garmin device (Photos: Rekittke).

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3.3 Post-processing of models

There are multitudinous possibilities of subsequent post-processing and optimisation of 123D Catch models. In this paper, we limit ourselves to bring up three interesting options, with reference to our intention to use the 3D work in analysis, design activity, project communication, and public participation. The chosen aspects correspond to three important expectations in our works: (a) Comprehensible documentation and interactive visualisation of the site; (b) Exploitation for a georeferenced 3D model of the urban landscape; (c) Interactive modifiableness in the course of design processes.

Iterative integration of partial improvers During the fieldtrip, after coming back to the hotel with first sets of field photography, the material can be uploaded via 123D Catch and inspected for the first time. Insufficiencies can be determined and potential improvers defined. Returning to the field, the specific sites (for improvers) are thoroughly photographed again and the material is uploaded, together with the initial set of photos. After the iterative integration of all necessary improvers, we can achieve a significantly refined model of comprehensible visual quality (Fig. 9).

Fig. 9: Quality of the 3D model can be improved by adding localised picture of objects into the working model to generate refined model segments (Sample: Ninsalam)

The software 123D Catch demands discrete, logic spatial entities to be able to process usable models. The assembly of the single parts into an overall model of the entire spatial unit (e.g. a street or specific spatial cross section) cannot be processed within the

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programme. For this purpose we export the files into obj-format and compose them in Rhinoceros 4.0.

Embedding into the digital globe Unfortunately, 123D Catch lacks geo-referencing. However, even in the toughest urban places, people have networked computers and know where they sit on the digital globe. Embedding 3D models into geo-virtual environments such as the digital globes Google Earth and Biosphere3D facilitates the intelligible discussion of planning and design decisions (SHEPPARD & CIZEK, 2008). This can be done via 3ds-format, using Google Sketchup 8 geo-referencing feature, which is saved in kmz-format (Fig. 10).

Fig. 10: Geo-positioning of a model in 3ds-format, using Google Sketchup 8 geo-referen-cing feature which is saved as kmz-file (Sample: Ninsalam)

Interactive modifiableness Supreme discipline of the GeoDesign foot soldier is the provision of sufficiently precise raw material from rough places, transforming it into a sophisticated 3D model – which then can be interactively modified, in order to display design alternatives. We started to export our Autodesk 123D Catch models as las-files into Autodesk Revit Architecture for future integration of 3D models of design proposals (Fig. 11). This is where we stand at the moment.

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Fig. 11: Exported 3D information in Autodesk Revit Architecture (Sample: Ninsalam)

4 Writing on the Wall

We seek to remain moderate and grounded. We love muddling through the toughest urban places on earth. We advocate the utilisation of inexpensive, ordinary tools, and technology and we are convinced that the aviators will always need the foot soldiers and vice versa. But we are not ignoring the writing on the wall. There is no way around more expensive tools like short and long range 3D laser scanners for detailed terrain measurement and documentation – which are available on the market and can be readily employed by the landscape architectural guild now. At present, we are not certain if we can use these more expensive and flamboyant tools for Grassroots GIS operations on the informal city grounds. Such doubts do not have monetary justification. They derive from the fact that any informal city quarter is built on politically and judicially shaky ground. The people living in these parts of the city are wary and justifiably so. Another problem might be security issues concerning the laser beam. We do not speak of beautiful empty landscapes or deserted, suburban bourgeois living environments. We roam constantly crowded and super narrow city layouts. The mounting of exclusion zones and running around in hard hats plus high visibility vests are unthinkable.

5 Acknowledgements

The research and fieldwork described in this paper could not have taken place without the MLA students from the National University of Singapore. Especially through their contributions on top of being lion-hearted, weatherproof, and ever willing to travel together with us foot soldiers, many thanks to all of them. We would also like to thank the NUS Department of Architecture for the lasting support – in face of our out of the ordinary travel

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destinations. Special thanks goes to Christophe Girot, in his capacity as head of the research module “Landscape Ecology” of the Future Cities Laboratory, Singapore-ETH Centre for Global Environmental Sustainability. He and his team at the interdepartemental ETH Landscape Visualization and Modeling Lab are our favourite aviators.

References

Autodesk 123D Catch (2012), URL (Feb. 2012): http://www.123dapp.com/catch. Cochrane, J. et al. (2009), Water Worries. Special Issue, Jakarta Globe Saturday/Sunday,

July 25/26, 2009. Flaxman, M. (2010), Fundamentals of Geodesign. In: Buhmann, E., Pietsch, M. & Kretzler,

E. (Eds.), Reviewed Proc. of Digital Landscape Architecture 2010 at Anhalt University of Applied Sciences, Berlin/Offenbach, Wichmann, 28-41.

Girot, C. & Rekittke, J. (2011), Daring Down the Plastic River in Jakarta. In: Topos, 77, 55-59.

Rekittke, J. & Paar, P. (2010), Grassroots GIS – Digital Outdoor Designing Where the Streets Have No Name. In: Buhmann, E., Pietsch, M. & Kretzler, E. (Eds.), Reviewed Proc. of Digital Landscape Architecture 2010 at Anhalt University of Applied Sciences, Berlin/Offenbach, Wichmann, 69-78.

Rekittke, J. & Paar, P. (2011), There is no App for that – Ardous fieldwork under mega urban conditions. In: Buhmann, E. et al. (Eds.), Reviewed Proc. (online version) of Digital Landscape Architecture 2011 at Anhalt University of Applied Sciences, 26-36.

Sheppard, S. R. J. & Cizek, P. (2009), The ethics of Google Earth: Crossing thresholds from spatial data to landscape visualisation. In: Journal of Environmental Management, 90 (6), 2102-2117

Texier, P. (2008), Floods in Jakarta: when the extreme reveals daily structural constraints and mismanagement. In: Disaster Prevention and Management, 17 (3), 358-372.