Ron van Lammeren

Multi-actor-based land use modelling: spatial planning using agents

This paper describes a spatial planning model combining a multi-agent simulation (MAS) approach with cellular automata (CA). The model includes individual actor behaviour according to a bottom-up modelling concept. Spatial planning intentions and related decision making of planning actors is defined by agents. CA is used to infer the knowledge needed by the agents to make decisions about the future of a spatial organisation in a certain area. The innovative item of this approach offers a framework for modelling complex land use planning process by extending CA approach with MAS. The modelling approach is demonstrated by the implementation of a pilot model using JAVA and the SWARM agent modelling toolkit. The pilot model itself is applied to a study area near the city of Nijmegen, The Netherlands.

The phenology and population dynamics of Culicoides spp. in different ecosystems in the Netherlands

The Netherlands has enjoyed a relatively free state of vector-borne diseases of economic importance for more than one century. Emerging infectious diseases may change this situation, threatening the health of humans, domestic livestock and wildlife. In order to be prepared for the potential outbreak of vector-borne diseases, a study was undertaken to investigate the distribution and seasonal dynamics of candidate vectors of infectious diseases with emphasis on bluetongue vectors (Culicoides spp.). The study focused primarily on the relationship between characteristic ecosystems suitable for bluetongue vectors and climate, as well as on the phenology and population dynamics of these vectors. Twelve locations were selected, distributed over four distinct habitats: a wetland area, three riverine systems, four peat land areas and four livestock farms. Culicoides populations were sampled continuously using CO(2)-baited counterflow traps from July 2005 until August 2006, with an interruption from November 2005 to March 2006. All vectors were identified to species level. Meteorological and environmental data were collected at each location. Culicoides species were found in all four different habitat types studied. Wetland areas and peat bogs were rich in Culicoides spp. The taxonomic groups Culicoides obsoletus (Meigen) and Culicoides pulicaris (Linnaeus) were strongly associated with farms. Eighty-eight percent of all Culicoides consisted of the taxon C. obsoletus/Culicoides scoticus. On the livestock farms, 3% of Culicoides existed of the alleged bluetongue vector Culicoides dewulfi Goetghebuer. Culicoides impunctatus Goetghebuer was strongly associated with wetland and peat bog. Many Culicoides species were found until late in the phenological season and their activity was strongly associated with climate throughout the year. High annual variations in population dynamics were observed within the same study areas, which were probably caused by annual variations in environmental conditions. The study demonstrates that candidate vectors of bluetongue virus are present in natural and livestock-farm habitats in the Netherlands, distributed widely across the country. Under favourable climatic conditions, following virus introduction, bluetongue can spread among livestock (cattle, sheep and goats), depending on the nature of the viral serotype. The question now arises whether the virus can survive the winter conditions in north-western Europe and whether measures can be taken that effectively halt further spread of the disease.

A longitudinal study on Anopheles mosquito larval abundance in distinct geographical and environmental settings in western Kenya

BackgroundAs the ecology of mosquito larvae can be complex there is need to develop a rational framework for undertaking larval ecological studies. Local environmental characteristics, such as altitude, climate and land use, can significantly impact on phenology and population dynamics of mosquito larvae, and indirectly affect the dynamics of mosquito-borne diseases. The aim of this study was to assess the feasibility of implementing an integrated approach to larval source management under the distinct ecological settings.MethodsThe study was conducted in two highland villages and one village, at a lower altitude, in the Lake Victoria basin, where malaria is endemic and transmitted by the same Anopheles mosquito species. In each village the stability of mosquito larval habitats was classified as either temporary or permanent. The productivity of these habitat types was quantified by carrying out weekly larval sampling using a standard dipping method for a period of two years. During sampling the physical characteristic of the larval habitat, including the vegetation cover were noted. Ambient temperature, rainfall and relative humidity were recorded on a 21 × Micro-datalogger in each study site.ResultsAnopheles gambiae sensu lato larvae were found in all study sites. Anopheles arabiensis was more abundant (93%) in Nyalenda (Lake Victoria basin) and Fort Ternan (highland area; 71%). In Lunyerere (highland area), An. gambiae sensu stricto comprised 93% of the total An. gambiae s.l. larvae. Larvae of An. gambiae s.l. mosquitoes were present in both temporary and permanent habitats with monthly variations dependent on rainfall intensity and location. Anopheles larvae were more likely to be found in man-made as opposed to natural habitats. Grassy habitats were preferred and were, therefore, more productive of Anopheles larvae compared to other habitat types. Weekly rainfall intensity led to an increase or decrease in mosquito larval abundance depending on the location.ConclusionThe majority of mosquito breeding habitats were man made in all sites. Both temporary and permanent habitats were suitable for An. gambiae breeding. In Fort Ternan temporary sites were favoured for mosquito breeding above permanent sites. Significant differences in larval abundance were found depending on weekly rainfall intensity. Larval source management programmes should target permanent and temporary habitats equally and work closely with land and home owners as a majority of the breeding habitats are man made.

Validation of an agent-based model for spatial planning: A role-playing approach

This paper discusses the validation of an agent-based model for simulating a multi-actor spatial planning process. After a general discussion about the pitfalls of validating agent-based models that simulate complex spatial systems, we briefly present a validation method based on role playing. The method is designed to generate insights that can improve our understanding of the behaviour of socio-spatial systems in a planning context. The method was tested by carrying out an experimental role play to validate individual agent tasks, focusing on the ability of agents to generate beliefs and preferences about their environment. We conclude that using role play as a validation technique can provide valuable information about the performance of the model. The insights gained aid identification and understanding of those parts of a multi-actor spatial planning system that are currently poorly understood and poorly represented by the agents.

Measuring the neighbourhood effect to calibrate land use models

Abstract Many spatially explicit land use models include the neighbourhood effect as a driver of land use changes. The neighbourhood effect includes the inertia of land uses over time, the conversion from one land use to another, and the attraction or repulsion of surrounding land uses. The neighbourhood effect is expressed in the neighbourhood rules, but calibration of the neighbourhood rules is not straightforward. This paper aims to characterise the neighbourhood effect of observed land use changes and use this information to improve the calibration of land use models. We measured the over- and underrepresentation of land uses in the neighbourhood of observed land use changes using a modified version of the enrichment factor. Enrichment factors of observed land use changes in Germany between 1990 and 2000 indicate that the neighbourhood effect exists. This suggests that it is appropriate to use neighbourhood rules to simulate urban land use changes. Observed enrichment factors were used to calibrate a land use model for Germany from 1990 to 2000 and the obtained neighbourhood rules were validated independently from 2000 to 2006. The results show that both the allocation accuracy and the pattern accuracy of the land use model improved for the calibration period, as well as for the independent validation period. This indicates that enrichment factors can be used to improve the calibration of the neighbourhood rules in land use models.

Specifying and Implementing Constraints in GIS--with Examples from a Geo-Virtual Reality System

Constraints are important elements of every modelling process, but until now they have been treated in an ad hoc manner, depending on the specific application domain and the capabilities of the tools used. In GIS and GeoVR applications, constraints are conditions which always have to be valid (true) within the model populated with real geographic object instances. This paper argues that constraints should form a systematic part of the object class definition, similar to other aspects of the definition, viz. attributes, methods and relationships. Also, the implementation of constraints in all GIS and GeoVR subsystems (at front-end, database and exchange (I/O) level) should be derived automatically from the constraints specified by the framework. The paper therefore puts forward a framework for modelling constraints comprising (1) a classification and clarification of constraints, (2) a formal description using the unified modelling language/object constraint language (UML/OCL) and (3) implementation characteristics. The components of the framework are illustrated and applied to SALIX-2, a geo-virtual reality (GeoVR) landscape modelling system.

Three sampling methods for visibility measures of landscape perception

The character of a landscape can be seen as the outcome of peoples perception of their physical environment, which is important for spatial planning and decision making. Three modes of landscape perception are proposed: view from a viewpoint, view from a road, and view of an area. Three sampling methods to calculate visibility measures simulate these modes of perception. We compared the results of the three sampling methods for two study areas. The ROPE method provides information about subspaces. The road method enables the analysis of sequences. The grid point method calculates visibility measures at almost every location in space, providing detailed information about transitions and pattern change between original and new situations. The mean visibility values for the study areas reveal major differences between the sampling methods. Combining the results of the three methods is expected to be useful for describing all the facets of landscape perception.

Species distribution models predict temporal but not spatial variation in forest growth

Abstract Bioclimate envelope models have been widely used to illustrate the discrepancy between current species distributions and their potential habitat under climate change. However, the realism and correct interpretation of such projections has been the subject of considerable discussion. Here, we investigate whether climate suitability predictions correlate to tree growth, measured in permanent inventory plots and inferred from tree‐ring records. We use the ensemble classifier RandomForest and species occurrence data from ~200,000 inventory plots to build species distribution models for four important European forestry species: Norway spruce, Scots pine, European beech, and pedunculate oak. We then correlate climate‐based habitat suitability with volume measurements from ~50‐year‐old stands, available from ~11,000 inventory plots. Secondly, habitat projections based on annual historical climate are compared with ring width from ~300 tree‐ring chronologies. Our working hypothesis is that habitat suitability projections from species distribution models should to some degree be associated with temporal or spatial variation in these growth records. We find that the habitat projections are uncorrelated with spatial growth records (inventory plot data), but they do predict interannual variation in tree‐ring width, with an average correlation of .22. Correlation coefficients for individual chronologies range from values as high as .82 or as low as −.31. We conclude that tree responses to projected climate change are highly site‐specific and that local suitability of a species for reforestation is difficult to predict. That said, projected increase or decrease in climatic suitability may be interpreted as an average expectation of increased or reduced growth over larger geographic scales.

Sensing Landscape History with an Interactive Location Based Service

This paper introduces the STEAD approach for interpreting data acquired by a “human sensor”, who uses an informal interactive location-based service (iLBS) to sense cultural-historic facts and anecdotes of, and in the landscape. This user-generated data is collected outdoors and in situ. The approach consists of four related facets (who, what, where, when). Three of the four facets are discussed and illustrated by user generated data collected during a Dutch survey in 2008. These data represent the personal cultural-historic knowledge and anecdotes of 150 people using a customized iLBS for experiencing the cultural history of a landscape. The “who” facet shows three dominant mentality groups (cosmopolitans, modern materialists and post modern hedonists) that generated user content. The “what” facet focuses on three subject types of pictures and four picture framing classes. Pictures of the place type showed to be dominant and foreground framing class was slightly favourite. The “where” facet is explored via density, distribution, and distance of the pictures made. The illustrations of the facets indirectly show the role of the “human sensor” with respect to the domain of interest. The STEAD approach needs further development of the when-facet and of the relations between the four facets. Finally the results of the approach may support data archives of iLBS applications.

Enhancing the Experience of the Landscape: The Digital Dowsing Rod

This research presents the Digital Dowsing Rod (DIWI1) a framework of a Location Based Service (LBS) to explore the cultural heritage of a region. The DIWI consists of a service oriented architecture (SOA), a web-client, a content management system and a mobile client based on smart phones and windows mobile technology. The chosen set-up allows for an easy management of the content and allows for a relative easy extension of the system by additional data-sources.