Yazar "Ipbuker, C" seçeneğine göre listele

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    Computer program for the inverse transformation of the Winkel projection
    (ASCE-AMER SOC CIVIL ENGINEERS, 2005) Ipbuker, C; Bildirici, IO
    The map projection problem involves transforming the graticule of meridians and parallels of a sphere onto a plane using a specified mathematical method according to certain conditions. Map projection transformations are a research field dealing with the method of transforming one kind of map projection coordinates to another. The conversion from geographical to plane coordinates is the normal practice in cartography, which is called forward transformation. The inverse transformation, which yields geographical coordinates from map coordinates, is a more recent development due to the need for transformation between different map projections, especially in Geographic Information Systems (GIS). The direct inverse equations for most of the map projections are already in existence, but for the projections, which have complex functions for forward transformation, defining the inverse projection is not easy. This paper describes an iteration algorithm to derive the inverse equations of the Winkel tripel projection using the Newton-Raphson iteration method.
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    Function matching for Soviet-era table-based modified polyconic projections
    (TAYLOR & FRANCIS LTD, 2006) Bildirici, IO; Ipbuker, C; Yanalak, M
    Some map projections are defined by table values rather than mathematical equations. The most popular and famous one in this category is the Robinson Projection. The Ginzburg projections, which were developed and used in the former Soviet Union, are among the other table-based world projections. A computational method is required in order to efficiently use these kinds of projections in Geographic Information Systems (GIS) and similar environments. Function matching for projections based on table values can be realized for a numerical forward transformation. Matched functions also allow the calculation of distortions in the projection easily. In this study, polynomials and radial basis functions, such as multiquadric and thin-plate spline functions, are applied to derive an analytical expression from an array of tabular coordinates. The tests are realized on three table-based polyconic projections, the Ginzburg IV, V and VI. The distortion characteristics of table-based projections are sought by using partial derivatives obtained through numerical approximation. The distortion analysis shows that the Ginzburg V has very reasonable distortions. A solution for the inverse transformation of these projections is also provided. With the awareness of such projections, more alternatives in seeking a suitable map projection in world-scale GIS applications can be proposed.
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    New local transformation method: Non-sibsonian transformation
    (ASCE-AMER SOC CIVIL ENGINEERS, 2005) Yanalak, M; Ipbuker, C; Coskun, MZ; Bildirici, IO
    Coordinate transformations refer to mathematical processing that enables overlay of digital maps that use different coordinate reference systems, that is, map projections. The transformation from geographical to map (plane) coordinates is the conventional practice in cartography, which is called forward transformation. The inverse transformation. which yields geographical coordinates from map coordinates, is a more recent development. due to the need for transformation between different map projections, e specially in geographic information systems (GIS). The combination of the inverse and forward transformation from one projection to another. which may be called grid-on-grid or map-to-map transformation. can be necessary for some custom applications in GIS and in automated cartography Many different approximation algorithms can be used for this problem on desktop computers. In this paper a new local transformation method called a non-Sibsonian transformation. which uses non-Sibson local coordinates. is suggested for map-m-map transformation or for improving geometrical accuracy of scanned maps. A case Study is performed using the Lambert conformal conic projection and is presented with results.