Proceedings, XXth congress: Proceedings, XXth congress

Altan, M. Orhan

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Multivolume work

Persistent identifier:: 1663674213

Title:: Proceedings, XXth congress

Sub title:: Istanbul, 12 - 23 July 2004

Year of publication:: 2004

Place of publication:: Istanbul

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 1663674213

Language:: English

Additional Notes:: Erscheinungsdatum des Originals ist aus dem Copyrightjahr ermittelt.; Auch bezeichnet als XXth International Congress for Photogrammetry and Remote Sensing

Editor:: Altan, M. Orhan

Corporations:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing, Commission Primary Data Acquisition

Adapter:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing, Commission Primary Data Acquisition

Founder of work:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing, Commission Primary Data Acquisition

Other corporate:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing, Commission Primary Data Acquisition

Document type:: Multivolume work

Volume

Persistent identifier:: 166368779X

Title:: Proceedings, XXth congress

Scope:: IV, 226 Seiten

Year of publication:: 2004

Place of publication:: Istanbul

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 166368779X

Illustration:: Illustrationen, Diagramme

Signature of the source:: ZS 312(35,B8)

Language:: English

Additional Notes:: Erscheinungsdatum des Originals ist aus dem Copyrightjahr ermittelt.

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: Altan, M. Orhan

Corporations:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing

Adapter:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing

Founder of work:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing

Other corporate:: International Society for Photogrammetry and Remote Sensing, Congress, 20., 2004, Istanbul; International Society for Photogrammetry and Remote Sensing

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2019

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: AN ALGORITHM FOR BUILDING FULL TOPOLOGY Chaoying HE, Jie JIANG, Gang HAN, Jun CHEN

Document type:: Multivolume work

Structure type:: Chapter

hul 2 00s. h ygon Node 2 3 0 OGY n tables ve been rdinates International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B-YF. Istanbul 2004 of the nodes and identified points, the coordinate sets of edges. Table 3 describes the structure of the input data. Coordinates | Coordinate Set of Coordinates of of Nodes Edges Node ID Edge ID Identified Points Identified Point ID x coordinate | The coordinate sets x coordinate y coordinate of points in one y coordinate z coordinate edge z coordinate Table 3 Structures of Input Data To build Edge-Node relation table, the essential idea is coordinate matching. If the coordinates of nodes match the coordinates of the from nodes or the end nodes in the set tolerance, note down the node ID in Edge-Node relation table. And the Node-Edge relation table is based on the former one. According to the from-node and end-node Id of every edge, we can easily get the edges at every node. The crux of the algorithm is to build what we define as special area topology, that is, to search the road segments around the area feature that are closest to it. From Fig. 4, we know that if we draw a radial downwards from the identified point (A), the edge (BC) that intersects with the radial first is one edge we want. So we may think that if the radial is dense enough, we can find all required road segments around the area feature (Fig.4). However, the fact is that we cannot draw all radials. In our algorithm, we transform the problem to the following steps. Above all, specify the begin edge of the search process by drawing a vertical radial as we describe above. Then, set the begin edge as the edge of current disposal (current edge for short) and identify the begin node and end node of current edge according the rules defined in our algorithm. Set the end node as the current node of the searching process. And then search another edge that is connected to the current edge at the current node and closest to the area feature based on Qi operator. And then set the searched edge as the current edge, the end node of the edge as the current node. The searching process circulates until the end node of the current edge is equal to the begin node of the begin edge. During the searching process, we employ Qi operator because it is more efficient than angle operator used before. We also need to correctly dispose the dangle edges that are valid to road network. More details can be gotten in the following section. N hel p ed Fig. 4 An intuitionistic method to search the road segments around the area feature 4.2 More Details Specify the begin edge and identify the begin node and end node of one edge: Draw a vertical radial downwards from the identified point. The Edge which intersects with the radial first is the begin edge in our algorithm. This process can be optimized by excluding the edges that cannot intersect with the radial rather than computing the intersect points between the radial and all the edges. The begin node of one edge is the frontal node of one edge in the counter-clockwise. In Fig. 4, BC is the begin edge that intersects with the vertical radial first and B is the frontal nodes of edge BC in the counter-clockwise. So B is the begin node of ed BC and C is the end node of edge BC. 5 ge Qi Operator: To search the next edge based on the current edge and the current nodes, we need an operator to compute the most appropriate edge, that is, the closest one to the polygon in the direction. Angle operator is employed in the original methods. In these methods the angle operator, tan” (x), needs to be computed. The computation of tan” (x) is time consuming. The present paper adopts Qi operator (Qi Hua, Liu WenXi, 1996) that saves the time and heightens the efficiency. The basic ideas of Qi operator are to represent the corresponding polyline on the boundary rectangle of the unit circle as the azimuth of the radial. The center of the unit circle is the end node of the current edge. In the Fig. 5, the coordinate of point O is (Xo, Yo). The point B, the coordinate of which is (X;, Y;) is the intersect point of the radial from O and the boundary rectangle. SetAx;7 X;- Xo, Ay;= Y;- Yo. In the different eight directions, the Qi operator of the azimuth can be represented as the following formula. 13

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