Outlines of wings from 127 species of North American mosquitoes were digitized. Comparisons were made among several different methods of reducing the information in the resulting coordinates to a series of descriptors that could be used in multivariate analysis. Methods included Fourier analysis of both radii and tangent angle change functions. In addi- tion, the relatively new method of elliptic Fourier analysis was tried. Cluster and ordination analyses based on the various sets of descriptors summarized well the pattern of similarities and differences in wing shapes, but clusters of similar wings do not agree well with traditional taxonomic groupings. The use of elliptic Fourier descriptors appears to be especially promising for future work. (Fourier analysis; morphometrics; mosquitoes; image analysis; feature extrac- tion.)

A comparison of fourier methods for the description of wing shape in mosquitoes (diptera: culicidae)

Spectral analysis

This paper defines the critical components of cartographic time and compares temporal and spatial topologies. Because time is topologically similar to space, spatial data structuring principles can be adapted to temporal data. We present three conceptualizations of temporal geographic information and select one as the most promising basis for a temporal geographic information system. This conceptualization creates a spatial composite of all geometric information (at all times), where each object has an attribute history distinct from that of its neighbors.

A Framework For Temporal Geographic Information

The Commission on Spatial Data Standards of the International Cartographic Association is working to define formal models and technical characteristics of Spatial Data Infrastructures (SDI). To date, this work has been restricted to the Enterprise and Information Viewpoints from the ISO Reference Model for Open Distributed Processing standard. The Commission has developed models for these two viewpoints. These models describe how the different parts of an SDI fit together in the viewpoints in question. These models should be seen as a contribution towards the overall model of the SDI and its technical characteristics. During the model development process, the roles of the different Actors in an SDI in the Enterprise and Information Viewpoints have also been identified in Use Case diagrams of an SDI. All the models have been developed using the Unified Modeling Language.

An initial formal model for spatial data infrastructures

An expanded definition for measuring shape in a geographic context is presented. Shape analysis is important in many geographic contexts such as studying the effects of urban development, measuring geographic characteristics of drainage basins, and examining the patterns of geologic formations.



This research implements and tests an approach to expand the current mathematical definition of shape and to measure shape for geographic applications, called the trivariate shape definition. The expanded definition involves identifying three characteristics to define shape: edge, elongation, and perforation. Indices to measure these characteristics were identified and applied to two different data sets. Analysis of results from these data sets suggests that the trivariate index clustered groups of objects based on shape similarity. The trivariate approach provides more flexibility to measure shape by relying on a more specific definition of shape.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1538-4632.2000.tb00419.x

A Shape Definition for Geographic Applications Based on Edge, Elongation, and Perforation

As the application of interactive computer graphic methods to cartographic tasks continues to develop and mature, it is useful and instructive to examine these developments in a deeper conceptual context. Possibilities for cartographic communication have been greatly expanded with such interactive cartographic computer systems. A key concept in the power and flexibility of such interactive systems is that of real and virtual maps and transformations that can be made between them. One can now look past current interactive cartographic systems for display, analysis and map production to the potential of more powerful and flexible real-time interactive cartographic systems which can deal with more complex forms of cartographic situations and include the manipulation of a number of aspects of spatiotemporal dynamics. These include cartographic object manipulation and surface exploration, the display of cartographic data as it changes through time, and combinations of the above.

Strategies of Real-time Cartography

The authors have developed an approach to the harmonic analysis of closed cartographic forms in the complex domain called Dual Axis Fourier Shape Analysis (DAFSA) which is a significant improvement over earlier harmonic shape analysis techniques. DAFSA is based on the variance spectrum and modulus ratio spectrum as the fundamental Fourier shape descriptors for analysis and interpretation. Any closed cartographic form can be decomposed into its respective harmonic frequency components which can be rationally interpreted in terms of the contribution that a specific frequency and related attributes of it are making to the shape in question. As such the DAFSA descriptors are independent of scale, translation, rotation and starting point of the figure.

Harold Moellering

Papers

Strategies of Real-time Cartography

The Dual Axis Fourier Shape Analysis of Closed Cartographic Forms