David N. Siriba

Market segmentation using geographic information systems (GIS): A case study of the soft drink industry in Kenya

Purpose – To show how the analytical and visualization capabilities of geographic information systems (GIS) can enhance the communication, understanding and utility of data and information to be used in marketing planning, as compared with their conventional presentation as text and tables.Design/methodology/approach – A digital map of the study area was generated and a set of market zones. A multiple regression model for predicting sale of the product under study was then developed, taking into account sales figures from specific distribution outlets and the demographic and socio‐economic characteristics of the population served by the distribution outlets in the identified market zones. Optimum routes and times between the manufacturing plant and the distribution outlets were derived.Findings – Combining geospatial methods with conventional marketing techniques enables users to visualize the spatial distribution of data in maps, complemented by various statistical graphs and diagrams. This form of prese...

ASSESSMENT OF KENYA'S READINESS FOR GEOSPATIAL DATA INFRASTRUCTURE TAKE OFF

Abstract Geospatial Data Infrastructure (GDI) is a concept that is a reality in most developed countries today. This concept is however only just beginning to take a foothold in most developing countries. This paper reports on a study to access Kenyas preparedness for GDI take off by evaluating the achievements made thus far in the basic components of GDI: data, technology, policies, institutional framework and people. It is observed that the relatively lukewarm political support and absence of a long-term strategic vision are serious constraints to GDI diffusion. Similarly, the lack of sustainable funding policies and strategies, coupled with the absence of a concise implementation strategy greatly undermine the development of GDI in Kenya. Most geospatial data sets are still in analogue form, are not regularly updated, and their consistency across organizations still needs to be verified. In addition, the absence of an active GIS professional organization greatly handicaps GDI development in Kenya. Nevertheless, despite this largely negative picture, the GDI status in Kenya compares well with those of most other African countries.

Automatic georeferencing of non-geospatially referenced provisional cadastral maps

Abstract This paper presents a methodology for the automatic georeferencing of provisional maps that have no geospatial reference grid. The methodology, which is a modification of the generalised Hausdorff distance registration measure, entails an iterative ranking process that consists of a set of qualitative statistical quantification to evaluate the correspondence of two datasets (pixel and object), overcoming data ambiguities, including outliers and noise. The automatic methodology presented can replace the preliminary requirement for initial manual or semi-automatic georeferencing of non-geospatially referenced data that are prone to error. It is a preliminary step in an overall data integration approach intended to enhance the geometric quality of such positional-approximated provisional maps to be used as qualitative spatial data infrastructure. A comparison of the proposed automatic georeferencing with the commonly used manual process showed better results, both in the number of point correspondences identified and in the final geometric alignment of provisional cadastral maps with a reference topographic dataset.

Reviewing the status of national spatial data infrastructures in Africa

The paper reviews the status of National Spatial Data Infrastructure (NSDI) in Africa, based on a survey conducted between April and October 2014. Web searches and data from the United Nations Department of Economic and Social Affairs E-Government survey of year 2014 were used to supplement the survey data. Using the SDI-Readiness methodology, the SDI-Readiness index is computed. Of the twelve countries reviewed, Senegal (0.69), Rwanda (0.65), South Africa (0.64) and Ghana (0.61) have higher indices; while Tanzania (0.33), Zimbabwe (0.33), Botswana (0.35) and Malawi (0.38) have lower indices. Countries with higher SDI-Readiness indices, which is a proxy for the capacity and willingness to develop an SDI, have a better chance of success in developing their NSDI. Lower indices implies that a lot more effort is required by the respective countries. Although all SDI components should be given equal prominence, the study suggests that more emphasis should be placed on improving the human and financial resources if Africa is to succeed in NSDI development.

Geometric quality enhancement of legacy graphical cadastral datasets through thin plate splines transformation

Abstract In some parts of the world, mainly developing countries, analogue graphical cadastral datasets are still being used, despite the fact that they usually contain large and differential positional distortions. This is because not only do they contain useful information, their replacement would involve lengthy legal procedures, huge financial costs and technical challenges as well. This paper presents a novel approach for the conflation of such legacy graphical cadastral datasets to more reliable and accurate topographical datasets based on the matching of linear features via a non-rigid transformation using thin plate spline transformation. The approach consists of three key steps: extraction of road network which is potentially contained in the graphical cadastral maps; matching of corresponding point and linear features between the extracted road network and a more reliable road network dataset; and computation of the non-rigid transformation between the datasets. Applying this reliable and accurate transformation quantification to the original legacy graphical cadastral dataset showed significant improvement in its geometric quality and positional accuracy.

Microwave Path Survey Using Differential GPS

Abstract A microwave path survey is critical before any wireless communication infrastructure can be put into place. It is on the basis of this that the line of sight possibility between any pair of stations is established. This survey can also be used to determine whether there is sufficient space available on existing telecommunication towers, where additional telecommunication facilities can be hosted. This study has demonstrated that differential GPS techniques can successfully be used in microwave path surveys within the framework of telegeoinformatics. The adopted methodology simulated a levelling circuit for the defined observation network. This resulted in an acceptable misclosure of 0.039m which was distributed among the various stations in proportion to the relative length of each link. Natural and man-made obstacles (critical points) along the various telecommunication links were also determined.

Linear Feature Alignment based on Vector Potential Field

An approach to align a linear feature in one dataset with a corresponding feature in another dataset that is considered more accurate is presented. The approach is based on the active contours (snake) concept, but implements the external force as a vector potential field in which case the source of the force is in vector form; further the snake feature is implemented as a non-closed snake. This is different from the conventional implementation of the snake, where the source of the external force is an image and the force is implemented as a gradient flow and usually as a closed snake. In this approach two conditions: the length and alignment conditions have to be satisfied to obtain a good alignment. Whereas the length condition ensures that the length of the snake feature is nearly equal that of the reference feature, the alignment condition requires that the snake and the reference feature are properly aligned. The length condition is achieved by fixing the end points of the snake feature to those of the reference feature. The alignment condition is achieved by segmenting the reference feature so that there is uniform external force from all parts of the feature. One assumption in this approach is that the snake and the reference feature are matched prior to alignment. An outstanding challenge therefore is to find out how to consider the effects of non-corresponding but neighbouring reference features on a snake feature in circumstances where prior matching has not been undertaken.