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The Earth–Sun Relationship
Published in Matt Fajkus, Dason Whitsett, Architectural Science and the Sun, 2018
To allow the specification of precise locations on Earth, a coordinate system known as the geodesic grid has been established (Figure 2.5). Any point on this spherical grid may be described with unique coordinates of latitude and longitude.
Ocean surface currents estimated from satellite remote sensing data based on a global hexagonal grid
Published in International Journal of Digital Earth, 2023
Wenbo Wang, Huijun Zhou, Senyuan Zheng, Guonian Lü, Liangchen Zhou
The second characteristic of a hexagonal grid is the system used to create hierarchical recursive subdivisions. In this paper, we use Icosahedral Snyder Equal Area (ISEA) projection and pole orientation to generate a geodesic grid system (Sahr 2011). Using aperture 4 for subdivisions; that is, the area of any upper level of grid cells is four times that of the next lower level. Figure 2 shows levels 5 through 8 of our grid generated by DGGRID (Sahr 2015). Table 1 provides the number of cells and comparable coordinate based resolutions for these four levels. However, we cannot use array indices directly unless a dedicated hexagon grid index system is available (Sahr 2019). Therefore, we use half-edge structure to construct the grid geometric topology (Mcguire 2000).
The Invisible Beauty of the Zeiss-Dywidag Domes: Topology Optimization of the Triangulated Rebar Grids
Published in International Journal of Architectural Heritage, 2023
Orsolya Gáspár, Alexandra É Kis
Historical details, necessary to contextualize Bauersfeld’s contribution to the theory of equivalent shells (Makowski 1984) are presented in Section 3. It is highlighted in advance that stability, specifically buckling of the girdshell is only briefly discussed, even though Bauersfeld’s documented interest in the problem. The second problem, the process of the optimization is interesting, as it is not obvious what necessitated the change from one topology to another. It has been clarified (Bauersfeld 1957) that the non-bearing grid (step 3) was favored because it allowed the structure to be thinner and lighter and it required less precision during construction. With the advancement of construction technology, the self-bearing grid became obsolete. However, the initial geodesic subdivision was a highly optimized design (Gáspár, 2022) which performed very well from a geometrical point of view: it had relatively few different edges (which is advantageous from a constructional point of view) and resulted in a very smooth surface. This was achieved by a uniform distribution of triangles — uniformity was measured by the ratio of longest and shortest edges (lmax/lmin) and was enforced by constraining the subdivision to be of equal area. Therefore, a natural question arises: In what regard was the lamella-type superior to the geodesic grid? (Section 5)