Tangible Modeling with Open Source GIS

The complex, 3D form of the landscape—the morphology of the terrain, the structure of vegetation, and built form—is shaped by processes like anthropogenic development, erosion by wind and water, gravitational forces, fire, solar irradiation, or the spread of disease. In the spatial sciences GIS are used to computationally model, simulate, and analyze these processes and their impact on the landscape. Similarly in the design professions GIS and CAD programs are used to help study, re-envision, and reshape the built environment. However, because of the unintuitive nature of understanding and manipulating 3D forms in abstract, digital space via a GUI, technologies like GIS are so challenging to learn and use that they restrict creativity. The limitations of the technology constrain how we think. Being able to interact more naturally with digital space enhances our spatial thinking, encouraging creativity, analytical exploration, and learning. This is critical for designers as they need to intuitively understand and manipulate information in iterative, experimental processes of creation. With tangible user interfaces (TUIs) like Tangible Landscape one can work intuitively by hand with all the benefits of computer modeling and analytics. This chapter discusses the evolution of tangible user interfaces and the development of Tangible Landscape, exploring its motivations, applications, and future directions. This chapter also describes the organization of this book.

The setup of the Tangible Landscape system consists of four primary components: (a) a physical model that can be modified by a user, (b) a 3D scanner, (c) a projector, and (d) a computer installed with GRASS GIS for geospatial modeling and additional software that connects all the components together. The physical model, placed on a table, is scanned by the 3D scanner mounted above. The scan is then imported into GRASS GIS, where a DEM is created. The DEM is then used to compute selected geospatial analyses. The resulting image or animation is projected directly onto the modified physical model so that the results are put into the context of the modifications to the model.

Tangible Landscape works with many types of physical 3D models. When used as a continuous shape display the physical model should be built of a malleable material such as sand, clay, or wax so that users can easily deform the surface. When used for object recognition the physical model can be built of a rigid material such as a wood product, plastic, or resin. When both modes of interaction are combined the physical model should use malleable materials for the base and rigid materials for the objects. These models can be built by hand or digitally fabricated using 3D printing or computer numerically controlled (CNC) manufacturing. The final model should be opaque, have a light color, and have a matte finish so that the projected image is crisp and vivid. Transparent materials like acrylic cannot be 3D scanned with a Kinect. Some 3D printing and casting materials like resin may appear opaque, but have translucent properties—this will diffuse the projection. If we desire a very crisp and vivid image on a rigid model made of wood products or resins we recommend painting the model white. In this chapter we discuss different types of physical models and explain how to fabricate them.

Tangible Landscape allows us to explore the spatial patterns of topographic parameters and their relation to basic surface geometry. We can easily sculpt a physical model of a landscape with our hands changing its topography. With Tangible Landscape we can analyze the topography of a landscape model and how it changes by continually 3D scanning the model and computing DEMs from the scanned point clouds using binning or interpolation. By computing basic topographic parameters, morphometric units, and DEM differencing we can map changes in elevation, slope, and landform as the model is modified. These maps are then projected over the physical model of the landscape so that we have near real-time feedback and can understand the impact of the changes we are making as we make them.

The topography of the Earth’s surface controls the flow of water and mass over the landscape. Modifications to the surface geometry of the land redirect water and mass flows influencing ecosystems, crop growth, the built environment, and many other phenomena dependent on water and soil. We used Tangible Landscape to explore the relationship between overland flow patterns and landscape topography by manually changing the landscape model while getting near real-time feedback about changing flow patterns. We coupled Tangible Landscape with a sophisticated dam break model to investigate flood scenarios after a dam breach.

Viewshed (visibility) analysis is used in many different fields for both practical and aesthetic applications. It can play an important role when planning new buildings or roads especially in urban settings where obstructed views may raise safety concerns. In recreation areas views of beautiful landscapes are highly valued and protected with great passion. Visibility analysis is also crucial when planning location of monitoring cameras or communication towers in order to maximize coverage. With the increasing availability of high-resolution DEMs and DSMs derived from lidar visibility analysis is becoming more accurate, broading the range of its applications. We used Tangible Landscape to analyze viewsheds on North Carolina State University’s (NCSU) Centennial Campus from different observer positions and explored how future development would affect the viewsheds. We introduced object recognition to collaboratively designate observer positions.

The design of a walking or hiking trail is based on fine scale topographic conditions and varied criteria specific to the particular context such as aesthetics, views, construction cost, and environmental sensitivity. As a result trail planning is typically a product of expert knowledge, field surveys, and creative design decisions—often made on site. However, when high resolution data is available geospatial modeling can be used to identify routes optimized for travel time and suitability. To design trails with Tangible Landscape we can hand place waypoints on a physical model and then the optimal network connecting the waypoints is computed in near real-time. This approach—hand placing tangible waypoints and computationally networking the waypoints—combines creative, collaborative decision making with mathematical optimization. In this chapter we explain the theory and methodology for designing trails with Tangible Landscape and then discuss a case study, the design of hiking trail scenarios for Lake Raleigh Woods, North Carolina.

Solar radiation (insolation) is the primary driving force for Earth’s atmospheric, biophysical, and hydrologic processes. Knowing the amount of radiation at different geographic locations at different times is therefore necessary in many fields including energy production, agriculture, meteorology, ecology, and urban planning. In this case study we model direct solar radiation and cast shadows in an urban setting to show how different spatial configurations of buildings change the amount of sunlight available throughout the day and the year.

Forest fires, whether naturally occurring or prescribed, are potential risks for ecosystems and human settlements. These risks can be managed by monitoring the weather, prescribing fires to limit available fuel, and creating firebreaks. With computer simulations we can predict and explore how fires may spread. We can explore scenarios and test different fire management strategies under different weather conditions. Using Tangible Landscape and the GRASS GIS wildfire toolset we simulated several wildfire scenarios. We tested different configurations of firebreaks on the physical model and evaluated their effectiveness.

In this chapter we discuss how to simulate inundation and flooding in coastal landscapes, explain workflows for developing storm surge and sea level rise scenarios, and present two case studies. The first case study is a series of storm surge and dune breach scenarios for a populated barrier island. The second is a design—informed by flood and erosion modeling—for resilient, sustainable guest housing at a coastal research institute.