J. Raul Ramirez

Automatic extraction of building statistics from digital orthophotos

In this paper we discuss uses of image segmentation, feature extraction and Bayesian networks for identifying buildings in digital orthophotos and the utilisation of the results for the automated computation of building statistics. Our work differs from previous attempts in a number of ways. Firstly, image segmentation is accomplished using an adaptive multi-scale method which brings together region and edge information to segment the image into regions. Secondly, automated building feature extraction (e.g. corners) is optimised to fit with expert human annotation performance. The third aspect of this work is the exploration of Bayesian networks as a method for fusing available information (ranging from corner information to solar angles as indicators of shadow location) to classify segmented regions as corresponding to buildings or not. Such processes then permit the automatic compilation of building statistics.

Digitalization of coastal management and decision making supported by multi-dimensional geospatial information and analysis

This paper summarizes the results and outcomes of our NSF Digital Government project. During four years, this project concentrated on investigating, integrating and developing geospatial technologies to enhance the operational capabilities of federal, state, and local agencies responsible for coastal management and decision making. Successful collaborations have been established among research laboratories and government agencies in the areas of data collection and analysis, hydrodynamic modeling, development of web-based systems, and real-world applications of research results.

Boundary detection by contextual non-linear smoothing

Abstract In this paper we present a two-step boundary detection algorithm. The first step is a nonlinear smoothing algorithm which is based on an orientation-sensitive probability measure. By incorporating geometrical constraints through the coupling structure, we obtain a robust nonlinear smoothing algorithm, where many nonlinear algorithms can be derived as special cases. Even when noise is substantial, the proposed smoothing algorithm can still preserve salient boundaries. Compared with anisotropic diffusion approaches, the proposed nonlinear algorithm not only performs better in preserving boundaries but also has a non-uniform stable state, whereby reliable results are available within a fixed number of iterations independent of images. The second step is simply a Sobel edge detection algorithm without non-maximum suppression and hysteresis tracking. Due to the proposed nonlinear smoothing, salient boundaries are extracted effectively. Experimental results using synthetic and real images are provided.

Development of a cartographic language

The development of a cartographic language for topographic maps is presented. Map components are identified as part of the analytical study of maps and based on these components the elements of the language, alphabet and grammar, are identified. Then, the alphabetic symbols together with the components of the grammar: operations, rules and writing mechanism, are discussed in detail.

Geographic Information Systems

A geographic imformation system (GIS) is a set of computer-based tools to collect, store, retrieve, manipulate, visualize, and analyze geo-spatial information (information identified by its location on the surface of reference, for example, the Earth). This article describes the major components of a GIS (hardware and software) with emphasis in the central processing units and peripheral device and major software components: collection, storage, retrieval, manipulation, query and analyze, and visualization. This discussion is followed by a discussion of applications in several fields using a set of examples to illustrate these topics. Then, the concept and implications of quality in GIS (spatial data quality, quality on embedded and external models) is discussed. Finally, some comments are presented over the future of GIS. Keywords: computer applications; geo-spatial data processing; query and analysis of geo-spatial data; visualization of geo-spatial data