Last Online Deposits Spatial Data in the Web

Last Online Deposits Spatial Data in the Web

Mohamed-Khireddine Kholladi (University Mentouri of Constantine, Algeria)
DOI: 10.4018/978-1-61520-789-3.ch015
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The posting of interactive mapping is essential for the dissemination of information to the general public and in all areas. All the elements constituting a spatial object are represented by agreements with symbols. Each element is represented at the level of reality. The posting of maps on the Internet can take many forms. It can be static maps, as a picture. Interactions with the user can be included on the maps produced. These are movements and functions of the zoom presentation (display information, change of scale, global view). At this level, it is also possible to examine, by selection of the objects represented on the map (common facilities). This level is commonly known as Web mapping. The dynamic mapping is used when information is to be renewed or if the geographical extent of the area is large. In this case, a server handles in real-time updated database to provide users answers to their complaints. The functions proposed in this case are close to those of GIS software (acquisition, manipulation, management and processing of geographical data). In this chapter we will explore the possibility of integrating a dynamic mapping on the Web.
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One Point On The Terrestrial Surface Localization

The altimetry permits to determine the height of one point that is expressed by the difference between the point and a surface of reference as the sea level. The geoids are the surface of reference for the observations of altimeter. The measure of the heights called levelling makes itself by lines, whose intermediate points are marked with the help of ankles implanted in the facades of the buildings. The set of these reference marks constitutes the network of levelling of the studied geographical zone. All information on these reference marks is listed by the direction of the land-registry of the wilaya.

The plane coordinates of one point are calculated near to the centimetre with the help of triangles, where we measured the angles and the distances with tachometers. To orient their observations, the geometers determined the coordinates of the mosques minarets or the water castles that represent very visible reference marks from afar. The administration of the land-registry and the topography manages the geodesic basis network composed of score thousand points. The system of positioning by GPS satellites (Global Positioning System) permits the precise determination of the coordinates of one point quickly on earth. To be able to produce a card or a plan from the measured data, we conduct calculations of a mathematical projection. Several geodesic systems exist. An important system is the WGS4 that is the basis of the GPS system (Laurini R. & Thompson D, 1992).

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