Towards extracting artistic sketches and maps from digital elevation models

The main trend of computer graphics is the creation of photorealistic images however, there is increasing interest in the simulation of artistic and illustrative techniques. This thesis investigates a profile based technique for automatically extracting artistic sketches from regular grid digital elevation models. The results resemble those drawn by skilled cartographers and artists.The use of cartographic line simplification algorithms, which are usually applied to complex two-dimensional lines such as coastlines, allow a set of most important points on the terrain surface to be identified, these form the basis for sketching.This thesis also contains a wide ranging review of terrain representation techniques and suggests a new taxonomy

Putting self on the map: An examination of user-driven mapping

This thesis advances the basic argument that many people have difficulty interpreting cartographic information because that information has not been provided to meet their needs. Map users are wrongly regarded as passive users of a finished product. Original work in this thesis attempts to make the wishes of map users more prominent in the mapmaking process. The research is based upon the presupposition that people conduct communicative activity as a ritual, the form of which is designed to advantage some participants while imposing on others. Cartographic communication is examined on this basis and the map, as a form of ritualised communication, is deconstructed to yield insight into the participants in the mapping process. This deconstruction takes the form of a critical review of historical and contemporary cartography. The discussion of cartographic communication leads to a number of important advances in cartographic theory. The author presents a model of the mechanics of cartographic communication, and discusses the evocation and recovery of meaning from maps with reference to a recently-developed psycholinguistic theory of communication. The significant contribution of this thesis is found in the examination of alternative map subject matter and form. A map form incorporating elements of time as well as space is argued to be of more relevance to many map users. Results from a number of tests demonstrate that this alternative map form is well suited to the representation of personal data. The user-driven generation of cartographic subject matter is tested by the construction and operation of a Geographic Information System (G.I.S.) into which users can contribute data. Recorded use of this system, named Tourist Info, demonstrates that groups of users who are often disadvantaged in the provision of traditional cartography find Tourist Info helpful. This thesis concludes that it is both theoretically and practically possible to provide map users with the opportunity to determine the form and subject matter of maps relevant to their needs

The Design and Implementation of a Prototype Geographic Information System Using a Novel Architecture Based on PS-Algol

This thesis is concerned with the design and implementation of a novel architecture for a geographic information system based on the use of a new database language called PS-algol, in conjunction with a hybrid database structure. The main aspects discussed within the context of this thesis are:- i) the definition of a database; ii) the components and functions of a database management system; iii) the features of PS-algol; iv) the new system architecture; v) the use of operational management system; vi) data entry as carried out by the system; vii) the facility for the cartographic representation of features; viii) data retrieval and its potential use; and ix) the generation of hard-copy output The thesis also includes a review of existing geographical information systems against which the novelty of the new approach can be judged

The efficient use of data from different sources for production and application of digital elevation models

The emphasis of the investigation reported in this thesis is on the use of digital elevation data of two resolutions originating from two different sources. The high resolution DEM was captured from aerial photographs (first source) at a scale of 1:30,000 and the low resolution DEM was captured from SPOT images (second source). It is well known that the resolution of DEM data depends a great deal on the scale of the images used. The technique for capturing DEMs is static measurement of the spot heights in a regular grid. The grid spacing of the high resolution DEM was 30 m, and of the low resolution DEM was 100 m. The aims of this thesis are as follows: 1. To assess the feasibility of using SPOT stereodata as a source of height information and merged with data from aerial photography. This is carried out by comparison of the elevation data derived from SPOT with the digital elevation data derived from aerial photography. From the comparison of these two sources of height information, some results are derived which show the possible heighting accuracy levels which can realistically be achieved. A systematic error in the estimated average of the elevation differences was found and many tests have been carried out to find the reasons for the presence of this systematic error. 2. To develop methods to manipulate the captured data. 2.1. Gross error (blunder) detection. Blunders made during the data capturing procedure affect the accuracy of the final product. Therefore it is necessary to trap and to remove them. A pointwise local self-checking blunder detection algorithm was developed in order to check the grid elevation data, particularly those which are derived from the second source. 2.2. Data coordinates transformation. The data must be transformed into a common projection in order to be directly comparable. The projection and coordinate systems employed are studied in this project, and the errors caused by the transformations are estimated. 2.3. Data merging. Data of different reliability have to be merged into a single set of data. In this project data from two different sources are merged in order to create a final product of known and uniform accuracy. The effect of the lower resolution source on the high resolution source was studied, in dense and in sparse form. 2.4. Data structure. To structure the data by changing the format in order to be in an acceptable form for DEM creation and display, through the commercially available Laser-Scan package DTMCREATE. 3. DEM production and contouring. To produce DEMs from the initial data and that derived from the two merged sources, and to find the accuracy of the interpolation procedure by comparing the derived interpolated data with the high resolution DEM which has been derived from aerial photography. Finally to interpolate contours directly from the "raw" SPOT data and to compare them with those derived from the aerial photography in order to find out the feasibility and capability of using SPOT data in contouring for topographic maps

Data bases and data base systems related to NASA's Aerospace Program: A bibliography with indexes

This bibliography lists 641 reports, articles, and other documents introduced into the NASA scientific and technical information system during the period January 1, 1981 through June 30, 1982. The directory was compiled to assist in the location of numerical and factual data bases and data base handling and management systems

Historiography of Space in Homer and Herodotos

The Homeric poems and the Histories of Herodotos are crucial to our understanding of the intellectual life of the ancient Greeks. They are the earliest extant poetry and the earliest extant prose; they have never been lost and have always been read. Knowledge of the external world and of other peoples, though far from formalised as the study of ‘geography’ in this period, is prominent throughout the poems and the Histories: most readers of the Iliad get a very strong impression of place from their interaction with the text: the plain before the great citadel of Troy where the battle is fought, and the homes of the Trojan allies. Similarly, the Odyssey persuades many that they know and can recognise Ithake and surrounding islands. The Histories are an encyclopaedia of geographical knowledge of fifth-century Greeks which, conspicuously, includes knowledge of Skythia, Egypt and Persia as ‘other’ lands. In spite of this strong impression of place enduring even into the modern world it is not easy to know exactly why and how it arises and what narrative structures and strategies create it. The Homeric poems and the Histories are fundamentally about people and places (not cosmologies, or plants, or machines). Their completeness and length make it possible to study the spatial concepts held by their creators in detail. The thesis offered is that there have been three largely independent approaches to understanding the thinking about space in these texts and that by studying these approaches we can learn more about what categories of space are presented, thus avoiding a petitio elenchi. The three approaches discussed with this purpose in mind are autopsy, or retracing of steps, graphic demonstrations, and linguistic analyses (for which I present a number of case studies)

Visual Descriptors: A Design Tool for Visual Impact Analysis

This study is concerned with the development of a practical and effective form of computer-aided analysis of the visual impact of building development in rural areas. Its contribution is fourfold. Firstly, a conceptual model has been developed for the process of seeing in the context of visual impact analysis. Secondly, a mathematical model for a consistent series of visual descriptors has been devised. Thirdly, a suitable design tool has been devised to make use of visual descriptors in visual impact analysis. Fourthly, visual descriptors have actually been implemented as computer software. The concept of visual impact analysis is defined and placed within the wider context of landscape research. The problems faced by a designer in the context of visual impact analysis are identified and the concept of a 'design tool' is introduced and defined. A number of existing computer software packages, intended or used for visual impact analysis, are reviewed critically. The concept of 'visual descriptors' as measures to be used by designers is introduced and examined critically. A conceptual model is presented for the process of seeing in the context of visual impact analysis. A range of possible measures for use as visual descriptors is presented and developed further into a series of precise definitions. A method of implementing visual descriptors is presented together with formal algorithms for the derivation of eight visual descriptors. A software package incorporating these descriptors is presented and verification and case studies of its use carried out. Visual descriptors, as implemented, are assessed for their effectiveness as a design tool for visual impact analysis.Strathclyde University Dept. of Architecture and Building Scienc

A Geographic Information System Supporting Ocean Institute Research on Benthic and Demersal Species in the San Pedro Channel

This project utilizes GIS to investigate changes in benthic and demersal habitats in the San Pedro Channel, off the coast of California, over time. This project will also use a variety of ESRI products. The work was carried out for the Ocean Institute at Dana Point, which functioned as the client institution for the project. The Ocean Institute is heavily involved in the gathering of sample data for the purpose of monitoring benthic and demersal species that are native to the San Pedro Channel, for the State of California. Using this system will enable the Institute to use its sample data to detect changes in the populations of various species due to the effects of ocean temperature change, and to determine the extent of correlation between the two phenomena. This GIS enables the client to produce maps that depict the location of the sample points of their surveys, and simple statistical charts that measure the level of correlation between the changes in frequency of species occurrence and changes in the ocean temperature. These maps and charts can be output in either paper or digital format and be updated in near real-time from the client’s server, and are designed to be understood by an audience comprised of students from elementary school through high school. This functionality supports the client’s stewardship of the Dana Point Marine Wildlife Sanctuary, as well as its stated objective to inspire all generations, through education, to become responsible stewards of our oceans

Data bases and data base systems related to NASA's aerospace program. A bibliography with indexes

This bibliography lists 1778 reports, articles, and other documents introduced into the NASA scientific and technical information system, 1975 through 1980