Combining spatial data with survey data improves predictions of boundaries between settlements

Studies of land-use change often require the combination of socioeconomic survey data with spatially continuous maps of land-cover change. One approach is to define maps of land ownership, assuming that all land-use change can be attributed to the owners or managers of each parcel of land. Unfortunately, records of administrative boundaries between towns and villages are commonly unavailable in developing countries and prohibitively costly or time consuming to map for individual projects. However, point locations of the settlements themselves can be obtained easily from existing maps or remotely-sensed imagery. In this paper we compare three methods – circular buffers, unweighted Voronoi polygons (sometimes referred to as Thiessen polygons) and multiplicatively weighted Voronoi polygons – for estimating boundaries between villages in an agricultural landscape in West Africa. The benefits and limitations of each approach are discussed, and their accuracy assessed using 98 independently collected GPS coordinates of village boundaries. We present a novel method for generating and optimising weights for multiplicatively weighted Voronoi polygons using survey data of village sizes from a subset of villages. By using both spatial information and survey data from villages, we show that multiplicatively weighted Voronoi polygons outperform other methods of predicting village boundaries, and increase the correlation coefficient between surveyed village area and mapped areas from 0.18 to 0.68 compared with more commonly used unweighted Voronoi polygons. Our method of weighting Voronoi polygons can be implemented with data and software commonly available to researchers and non-governmental organisations.Funding for this research was contributed by the Cambridge Conservation Initiative and the Natural Environment Research Council (NE/H52449x/1).This is the author accepted manuscript. The final version is available from Elsevier via https://doi.org/10.1016/j.apgeog.2016.09.00

A Method Using GIS Integrated Voronoi Diagrams for Commuter Rail Station Identification: A Case Study from Brasilia (Brazil)

AbstractThis article describes a station location method for a commuter rail system applying a GIS integrated Voronoi diagrams. The method comes from a previously defined track line and considers the stations area coverage. As parameters to define area coverage we first used the point density representing the maximum concentrated activity area. We also use the trip generating rate weights for point density. The method was applied to Brasilia Metropolitan Area, and the final product was a “T” Trunk-Feeder framework that allows an integrated transportation system planning considering others existing transit systems. The stations were classified according to their degree of activities density and its importance for integration. The “T” Trunk-Feeder is a representation of the commuter rail network and the Trunk-Distribution is the transport network responsible for distributing the passengers in central business district - CDB. The proposed model features 69km extension, with the estimated total travel time of 62minutes, and 17 stations being integrated into 2 metro, 4 integrated into LRT stations and 3 integrated into the bus stops

ZONALNA PROCJENA I INTERPOLACIJA KAO ISTOVREMENI PRISTUPI U SLUČAJU MALOG ULAZNOG B ROJA PODATAKA (PRIMJER POLJA ŠANDROVAC, SJEVERNA HRVATSKA)

The Bjelovar Subdepression area in Northern Croatia was analysed, especially the Šandrovac Field that is located in the northern part of the subdepression. In this example, e-log depth marker Z’, i.e. the Pannonian and Pontian boundary, was used as an input data. The data were statistically analysed for the entire subdepression from 497 data readings from the regular grid with cell size of 1x1 km that covers the existing palaeostructural map. Then is selected 18 well data within the Šandrovac Field where e-log markers are recognised (an example of a small number of data). They are also read directly for given structural map and mapped using one of the declustering methods known as Thiessen polygon method or Kriging. It is concluded when the mapping includes small number of data, and consequently local uncertainties, the subsurface mapping need to be done on both ways and maps compared.Analiziran je prostor Bjelovarske subdepresije, osobito polje Šandrovac koje se nalazi u sjevernom dijelu. U ovom primjeru kao ulazni podatci uporabljene su dubine EK-markera Z\u27, tj. granice panona i ponta. One su statistički analizirane na razini cijele subdepresije iz 497 podataka očitanih iz pravilne mreže s ćelijama veličine 1x1 km kojom je prekrivena postojeća paleostrukturna karta. Nadalje, odabrano je 18 bušotinskih smjestišta unutar polja Šandrovac gdje su karotažom određene dubine markera (primjer malog ulaznog broja podataka). I oni su očitani izravno sa spomenute karte te kartirani jednom od deklasterizacijskih metoda, tj. metodom Thiessenovih poligona ili kriginga. Zaključeno je kada kartiranje uključuje značaje lokalne nesigurnosti te mali broj podataka, opravdano je dubinsko kartiranje na oba prikazana načina te usporedba rješenja

Estado del arte en procesos de zonificacion

Los procesos de partición espacial implican la división de un espacio geográfico en diferentes unidades o zonas según un conjunto específico de criterios. En ámbitos relacionados con las ciencias geoespaciales, la delimitación de estas zonas se realiza por agrupación de otras unidades básicas de área existentes en el espacio de trabajo. En este artículo se ofrece una revisión de los métodos de solución diseñados para este tipo de problemas, comenzando por una introducción a las técnicas heurísticas y modelos matemáticos más utilizados desde los años 60, para finalizar describiendo los recientes algoritmos aplicados a diagramas de Voronoi. También se revisan las aplicaciones en las que se han implementado algunos de estos modelos, quedando patente que son herramientas diseñadas para el tratamiento de problemas específicos, dada la dificultad de diseñar modelos genéricos y versátiles para este tipo de particiones espaciales o zonificacione

Exposures at Day Labor Corners: Using Existing Georeferenced Data to Describe Features of Urban Environments

PURPOSE: Latino day laborers are male immigrants from mainly Mexico and Central America who congregate at corners, that is, informal hiring sites, to solicit short-term employment. Studies describing the occupational environment of Latino day laborers traditionally measure jobsite exposures, not corner exposures. We sought to elucidate exposures at corners by describing their demographic, socioeconomic, occupational, business, built, and physical environmental characteristics and by comparing corner characteristics with other locations in a large urban county in Texas. METHODS: We used multiple publicly available data sets from the U.S. Census, local tax authority, Google\u27s Nearby Places Application Programming Interface, and Environmental Protection Agency at fine spatial scale to measure 34 characteristics of corners with matched comparison locations. RESULTS: Corners were located close to highways, high-traffic intersections, hardware and moving stores, and gas stations. Corners were in neighborhoods with large foreign-born and Latino populations, high rates of limited English proficiency, and high construction-sector employment. CONCLUSIONS: Publicly available data sources describe demographic, socioeconomic, occupational, business, built, and physical environment characteristics of urban environments at fine spatial scale. Using these data, we identified unique corner-based exposures experienced by day laborers. Future research is needed to understand how corner environments may influence health for this uniquely vulnerable population

Districting Problems - New Geometrically Motivated Approaches

This thesis focuses on districting problems were the basic areas are represented by points or lines. In the context of points, it presents approaches that utilize the problem\u27s underlying geometrical information. For lines it introduces an algorithm combining features of geometric approaches, tabu search, and adaptive randomized neighborhood search that includes the routing distances explicitly. Moreover, this thesis summarizes, compares and enhances existing compactness measures

LandParcelS: A module for automated land partitioning

Land fragmentation is a widespread problem and schemes for consolidating land are required to improve agricultural efficiency. This paper explains the development of a module called LandParcelS (Land Parcelling System) that is part of an integrated planning and decision support system called LAONISS which is being developed to assist land consolidation planning in Cyprus. LandParcelS is the component of the system that automates the land partitioning process by optimising land parcels in terms of shape, size and value. The methodology employs a genetic algorithm and results are presented when treating the partitioning task as either a single or multi-objective problem

Allocation of annual electricity consumption and power generation capacities across multiple voltage levels in a high spatial resolution

The electrical energy system is in transition. There is continuing expansion of renewable generation, which causes a spatial and temporal shift of energy flows at different voltage levels of the power grid. On the consumption side, demand patterns are expected to change. The limited availability of data with high spatial resolution hinders independent and transparent assessments. In view of this, the research project open_eGo is developing methods focusing on electricity networks and open-science principles. In this work, electricity demand and power generation are allocated to their corresponding voltage levels and network nodes. By combining data on municipal boundaries with Voronoi cells we created catchment areas for each substation. On the demand side, OpenStreetMap data is used for mapping different demand sectors. We show that a consistent data set can be produced in a high spatial resolution using geographical data processing. Our results apply to Germany but the methodology can be adopted to other countries or regions where sufficient open data is available