SVIBOR - Project code: 2-12-146

MINISTRY OF SCIENCE AND TECHNOLOGY

Strossmayerov trg 4, HR - 10000 ZAGREB
tel.: +385 1 459 44 44, fax: +385 1 459 44 69
E-mail: ured@znanost.hr

SVIBOR

SVIBOR - Collecting Data on Projects in Croatia

Project code: 2-12-146


CARTOGRAPHY AND GEOINFORMATION SYSTEMS


Main researcher: FRANČULA, NEDJELJKO (12275)


Assistants
Type of research: applied
Duration from: 01/01/91. to 12/31/94.
Papers on project (total): 244
Institution name: Geodetski fakultet, Zagreb (7)
Department/Institute: Institute of cartography
Address: Fra Andrije Kačića Miošića 26
City: 10000 - Zagreb, Croatia
Communication
Phone: 385 (0)1 4561 225
Phone: 385 (0)1 4561 222 / 176
Fax: 385 (0)1 445 410
Summary: The theory of cartographic projections has been developed on the basis of analytical geometry, linear algebra and differential geometry oriented towards the direct computer application. The equations of the normal aspect of central perspective conic projections of the sphere have been derived, and the algorithms for the calculation and the diagram of distortions have been worked out. The modifications of the Gilbert's projection have been carried out and the formulas for calculating distortions suitable as well for computer assisted graphic presentations have been derived. Searching the optimal modern algorithms for computations in the Gauá-Krger projection, some tasks of a current interest for Croatia have come in the foreground: determination of the air cooridor intersections with the state border and the determination of the territorial units area, the area of the Croatian sea and the area of the epicontinental belt. The algorithms have been worked out for calculating the intersection of the air corridors with the state border and for determing the area with the accuracy estimation of territorial units on the basis of digitized borders from the maps in Gauá-Krger projection. It has been proved that by means of this method the area can be determined with very high accuracy even from the map at the scale of 1:1 000 000. Thus the so far unknown area of the Croatian Sea and of the epicontinental belt have been determined. The computer program for affine transformation of coordinates between the old coordinates systems at the territory of Croatia and the system of Gauá-Krger projection has been designed on the basis of 14 datafiles of identical points and one datafile of the transformation coefficients. After analysing more than a hundred algorithms, the best algorithm today, regarding the distribution of errors for the calculation of ellipsoidal coordinates from the spatial rectangular coordinates, has been worked out. The algorithm efficiency for calculating the geodetic altitude from the isometric latitude has been analysed. A few of our own algorithms have been suggested. After our modification, the Bowring's algorithm proved to be the most efficient. The algorithms for mapping a sphere to the rotational ellipsoid and vice versa by using trigonometric series have been developed. For the purpose of differentiating the objects on the maps today's CAD and GIS packages have numerous areal patterns at their disposal which, however, are not always sufficient. Therefore we have generated our own new patterns. When the patterns are generated through the application of graphic variable "tone value", then the number of selectable degrees is limited. The researches have shown, that at the most seven degrees of the tone value can be used.

Keywords: computer cartography, map projections, Gauá-Krger projection, thematic maps, geoinformation systems

Research goals: To develope a modern theory of map projections on the basis of analytical geometry, linear algebra and differential geometry oriented towards the direct application of computer. Through the application of thus developed theory to research some so far less known projections: perspective conic, Gilbert's projection. For the purpose of state surveying and production of topographic maps in the majority of the countries in the world, the Gauá-Krger projection is used. According to our evaluation, there are no optimal solutions for solving the geodetic problems in that projection. Therefore, the outmost goal in the modernization of the algorithms for computation in the Gauá-Krger projection is to develope one's own software on the basis of the new and modern algorithms. The transformation of the map contents from one cartographic projection into the other has so far been practically an unsolvable problem in most of the cases. The computer assisted methods have enabled efficient solution of this problem being very important in the formation of geoinformation systems. The goal of our researches is to examine the existing procedures and to suggest new procedures together with their evaluation. Furthermore, it is to be found out, to which extent the areal patterns available in today's CAD and GIS packages meet the cartographic demands for the differentiation of objects on maps.

OTHER ACHIEVEMENTS


  1. Name: Bibliografija geodetskog lista 1947-1990
    Type of achievement: Catalogues, address books,
    Authors: Frančula N., Božićnik M., Vučetić, N., Petrović S.
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Last update: 10/22/95
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