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Testing GeoDesign in Landscape Planning – First Results

Christian ALBERT and Juan Carlos VARGAS-MORENO

1 Introduction

One of the fundamental aspects that is rapidly changing in design and planning is the process by which designs are generated and developed (VARGAS-MORENO 2008). In this context, computer-aided design tools and approaches are introduced that may provide planners and designers with immediate feedback on the potential impacts of their propositions, thus potentially enhancing design processes with real-time information on design implications and opportunities for greater involvement of non-experts.

GeoDesign is at the epicenter of these discussions. GeoDesign is “a design and planning method which tightly couples the creation of a design proposal with impact simulations informed by geographic context” (FLAXMAN 2010a, b). The GeoDesign concept has been proposed and fostered mainly through a series of international conferences organized by ESRI, the leading company for GIS software solutions, and has gained increasing attention over the last three years. GeoDesign conceptually builds upon the traditional design approach of sketching an idea, evaluating it, and redrawing the design. What makes contemporary approaches to GeoDesign unique however is the exploitation of nowadays available technology to provide rapid, model-based feedback on different design proposals.

Landscape planning offers a potentially very useful field of application of GeoDesign-approaches. Landscape planners often use scenarios as a basis for simulating and assessing possible future landscape configurations (alternative futures). A GeoDesign approach to landscape planning would enable planners to much more rapidly develop, alter and evaluate alternative futures. This could ease the participation of affected and interested parties in the planning process.

Research gaps exist on the one hand concerning the practical implementation of the GeoDesign-approach in landscape planning. On the other hand, the potentials and limitations of providing rapid, modeling-based feedback in participatory planning processes have not been thoroughly explored.

2 Research Objective and Methods

As a first steps towards exploring the usefulness of a GeoDesign-approach in landscape planning practice, one objective of this contribution is to explore how GeoDesign can be implemented in landscape planning within the ArcGIS software environment. Another objective is to discuss the opportunities and limitations of the currently available tools for using a GeoDesign approach to landscape planning in practice.

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The research questions are: 1. Which steps does a GeoDesign process consist of and which tools for implementing

them are already available in ArcGIS 10? 2. How can the identified GeoDesign tools be used to support landscape planning? 3. Which opportunities and limitations do current tools exhibit for application in planning

practice?

Questions two and three will be explored on the basis of an exemplary test in a planning study for the region of Hanover, Germany. The region was selected due to the availability of detailed spatial data and the diversity of site conditions. The planning process focuses on the development of two scenarios of future landscape development, and exemplary evaluates their respective impacts on biodiversity. The two scenarios are understood as extreme options for landscape development that are both unlikely to occur as proposed, but nevertheless frame the development corridor within which landscape change will probably take place.

The research methods can be sorted to three parts: First, available literature and online resources are reviewed. This section results in the development of a framework of essential components of a Geo-Design process. Then, publications and online resources are used to identify tools and extensions currently available for ESRI’s ArcGIS 10 for conducting these steps. The identified tools and extensions are then mapped to the components of a GeoDesign framework, resulting in an overview of available methods for each step.

Afterwards, the GeoDesign tools are applied in the landscape planning case study. The planning process consists of five steps:

1. Developing a conceptual model for assessing biodiversity 2. Translating the conceptual model into the model builder 3. Defining and simulating two extreme scenarios for landscape development 4. Assessing and reporting the impacts of the two scenarios on biodiversity

Finally, they application of the tools is critically discussed concerning its opportunities and limitations.

It is important to emphasize that the herein described study is only a first step for testing and evaluating the usefulness of a GeoDesign approach to landscape planning. More sophisticated simulations of land use changes in each scenario, as well as more elaborated and evidence-based assessment methods for evaluating biodiversity and other landscape functions would be needed in real planning applications. The case study therefore only presents preliminary results on opportunities and limitations of the use of contemporary GeoDesign tools in landscape planning, based on a critical evaluation from the planners’ perspective.

3 Results

3.1 Basic components of GeoDesign

Interestingly, a search on the ISI web of science for the term “geodesign” as the topic or title reveals only two references, of which one is a two-page Croatian article from 2011, and the other an Austrian article from 1994. Therefore, the following review is based on other peer-reviewed publications, in particular DANGERMOND (2010) and FLAXMAN

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(2010a) as well as grey literature (including ABUKHATER & WALKER 2010, DANGERMOND 2009, VARGAS MORENO 2010). Taken together, the literature argues that GeoDesign process includes at least the following three components:

The input process (a.k.a the design): A sketching interface that allows for rapid generation of alternative designs consisting of spatial features with attributes in a geographic context.

The evaluation (a.k.a the impact): A set of spatially informed models that assess the potential impacts of an entered design based on a series of evaluation parameters, and

The result: ( a.k.a the report): The instrument that communicates the outcomes of the impact evaluations in rapid, predetermined and understandable ways. The fast feedback then serves as input for another iterative cycle of sketching and evaluation.

3.2 Tools and methods for implementing GeoDesign with ArcGIS 10

The review of publications on the ArcGIS 10 software package (e.g. ALLEN 2011, HARDER et al. 2011, ORMSBY et al. 2010) shows that no comprehensive documentation is so far available of which tools can be used for implementing the entire GeoDesign process in a planning project.

The currently available methods for GeoDesign with ArcGIS 10 are summarized in table 1. For each component of the GeoDesign workflow, some tools are already existent. Other findings include:

Sketching is implemented by a new feature of ArcGIS that was formerly known as the ArcSketch extension (but requires some level of customization).

A useful approach for conducting rapid impact evaluations is to create a (simple) impact evaluation model in the model builder and defining it as a new tool. This tool is then readily available for impact evaluations. When started, it will prompt for the input layer to use, and then conduct the analysis.

Reporting the results of the rapid impact evaluations can be accomplished in three ways: the display of the maps created by the impact models, tables that summarize the spatial extend of areas that fulfill specific criteria, and diagrams. In addition, a new ESRI prototype, called dynamic charting, has been recently released for rapidly creating and dynamically updating charts that summarize a given field of a data source (e.g. costs or area). A significant issue identified is the restriction to move from reports back to design or evaluation seeking iterative improvements. Other constraints will be discussed in full manuscript.

Component I: Sketching

Component II: Impact evaluation

Component III: Reporting

Editable templates for ArcMap s included in mainstream ArcGIS 10 (formerly the ArcSketch extension)

Creating an impact evaluation model in model builder

Displaying maps that result from impact evaluation modeling

Displaying tables and charts that summarize the results

Table 1: Method components and tools for Geodesign currently available in ArcGIS 10

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Taken together, the review has shown that tools already exist in ArcGIS to fulfil the core ideas of GeoDesign, but all require substantial customization or advanced knowledge of the software platform.

3.2 Test of the tools in the case study region

The region of Hanover has been established in 2001 in a unification of the former communities of the city and the surrounding county of Hanover. Hanover region encompasses about 230,000 hectares and is home to about 1.13 Million inhabitants. The region is at the transition between the North-German plain and the low mountain ranges of central Germany. The northern part of the region is a typical moor geest landscape dominated by moor or sandy soils, pine forests, grasslands and fields. The southern part of the region includes the fertile soils of the Hildesheimer Börde and parts of the Deister mountain range. The Leine is the main river, trespassing the region from south to north.

The land use data for the case study is derived from a detailed land use map based on CIR interpretation of aerial imagery. In order to make the land use map manageable, the originally large number of land use classes was synthesized into ten land use types.

3.2.1 Conceptual model for assessing biodiversity

The literature shows various modeling approaches for assessing biodiversity. For example, WALDHARD et al. (2004) developed a model that estimates and predicts plant species richness at the local to regional scale based on an empirical assessment. This study uses an approach proposed by von DRACHENFELS (2004) that employs the importance of biotope types for nature conservation as a proxy for biodiversity. Each biotope type is evaluated on a five point scale with reference to the situation in the state of Lower Saxony. Four evaluation criteria are used: (i) ‘closeness to natural conditions’, (ii) endangerment, (ii) rareness, and (iv) importance as habitats for plant and animal species. In order to make the von Drachenfels-method applicable to the land use maps of the case study, a raster scheme needed to be derived that connected the ten land use types with the respective value for biodiversity (see table 2).

Land use type Biodiversity value

Moor 5 Very high importance

Grassland 4 High importance

Forest 3 Medium importance

Moor (degenerated) 3 Medium importance

Fields 2 Low importance

Grassland (intensively used) 2 Low importance

Infrastructure 0 Not evaluated

Settlement area 0 Not evaluated

Waters 0 Not evaluated

Other land uses 0 Not evaluated

Table 2: Evaluation table of land use types and respective biodiversity value (summarizedand altered from DRACHENFELS (2004))

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3.2.2 Translation of the conceptual model into the model builder

The ArcGIS model builder is used to develop a model for evaluating biodiversity (see figure 1) according to the evaluation rules defined in section 3.2.1. Input data for the evaluation of scenario impacts on biodiversity include (i) a shapefile with the land use configuration of the alternative future to be evaluated, (ii) an evaluation table (see table 1), and (iii) a symbology layer that defines the color code for illustrating the five levels of importance for biodiversity.

Fig. 1: Model structure for evaluating biodiversity

The developed model first joins the evaluation table with the attribute table of the alternative future land use map. Then, each feature in the shapefile will be attributed a biodiversity value according to the respective land use. The symbology is altered to no longer refer to the land use, but to the biodiversity value of each feature. In addition, a table is created that lists the area attributed to each level of importance. Fields in figure 1 that are indicated with a ‘P’ need to be checked and potentially altered by the user in each cycle, including the input files and the names and folders for the created files to be saved.

3.2.3 Definition and simulation of two extreme scenarios

Two scenarios are developed in the case study. The first scenario is termed “Bioenergy” and assumes that the production of biomass for bioenergy is strongly increased. The second scenario, “Climate mitigation”, assumes that all arable land on organic and alluvial soils (moor and floodplains) is converted to grasslands (Table 3).

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Land uses type in scenario “Status quo”

Land use type in scenario “Bioenergy”

Land use type in scenario “Climate mitigation”

Grassland Fields Grassland

Fields (on organic and alluvial soils)

Fields Grassland

Fields (all other areas) Fields Fields

Table 3: Transition rules for the two scenarios to create alternative futures

The simulation of land use changes in each scenario followed the transition rules listed in table 3. Plots of land were selected that fulfilled the land use type criterion, or the combination of land use type and soils criteria. The attributes of the selected plots were subsequently changed to represent the land use type of the respective scenario.

3.2.4 Assessment and report of impacts of the two scenarios on biodiversity

To assess the impacts of the two scenarios, the respective alternative futures were used as input for the developed models in the ArcGIS model builder environment. The resulting evaluation maps were color coded for the respective importance of each polygon on the 1 to five scale. Furthermore, the respective distribution of areas for each level of importance was summarized in a table, and illustrated in a bar chart for comparison (figure 2).

Fig. 2: Simulated land use changes as well as impact evaluation maps and reports

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4 Discussion and Conclusions

The herein described study used a limited land use data set of only ten classes, two extreme scenarios, and only a simple impact evaluation model. The results therefore should not be understood as detailed recommendations for planning, but rather as stylized study examples for testing a procedure for implementing GeoDesign in landscape planning.

The study has shown a few opportunities and limitations. The following opportunities were identified:

Transferring the impact evaluation concept into a model in the ArcGIS model builder was possible. The model builder environment allowed for detailed customization of the model to the specific planning needs. Developed models can be saved and used to evaluate different land use maps that follow a pre-defined land use coding.

Translating the simple land use conversion rules of the scenarios into GIS was easily doable using simple feature selection and attribute change commands.

Limitations that became apparent relate mainly to the question of how useful the developed GeoDesign procedure would be in landscape planning practice:

Customizations of models in the model builder can often not be conducted within a participatory planning session. Changing and pre-testing of models requires advanced knowledge and may take quite some time.

While executing the evaluation model in the case study was possible within a few seconds, a test with a more complex model showed that the modeling time can strongly increase to about two or more minutes. Studies that employ large datasets and/or complex models should therefore consider using distributed computing power in the cloud.

The need for tools to intuitively respond to the design-evaluation process in iterative ways has not yet been resolved. However, some discussions has started directing the characteristics of such systems (LEE 2010, VARGAS MORENO 2010).

Most importantly, what is needed what is a way to develop a front-end appearance for ArcGIS that combines the sketching, impact evaluation and reporting components in a common interface that is intuitively usable for diverse audiences. This front-end appearance should be web-based to provide access also to users that do not have access to computing power and the ArcGIS software.

Issues for further research include (a) further developing the scenarios and models and adding additional impact evaluation models, (b) testing the approach with real stakeholders, (c) investigating the reactions and effects of the use of the GeoDesign approach in a participatory planning process on participants’ perceptions and decision making (do they find it useful?), (d) further developing the software interface for non-experts, and (e) developing and evaluating options for transferring a front-end version of the GeoDesign planning process to the web.

5 Acknowledgements

The authors thank Johannes Hermes, Svenja Heitkämper, Rebekka Hofmann, Christiane Hörmeyer, Angelika Lischka, Felix Neuendorf, and Pia Wedell for support in conducting the analyses in the case study. Johannes Hermes also helped preparing the graphics. The

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study is related to the research project “Sustainable use of bioenergy: bridging climate protection, nature conservation and society”, lead by the Interdisciplinary Centre for Sustainable Development at Georg-August-Universität Göttingen and, in part, the Institute of Environmental Planning at Leibniz Universität Hannover.

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