Lines And Polygons Essays - Geographic Information Systems

Lines And Polygons Essays - Geographic Information Systems Lines and Polygons ? Other objects like lines (roads) and polygons (areas, minefields) are more complicated to handle and will need trained personal (if they're entered and maintained within the GIS). ? If data concerning the state of roads and bridges is necessary to be easily retrieved it might be necessary to create a special form for handling such information. It shouldn't be in the existing reports, because they are snapshots of progress and are being used for documentation ? The base coordinate system for displaying and querying geographical data at the GIS Lab in (and probably in general) is Longitude, Latitude. This is mainly because using GPS Receivers can easily collect data. Within Somalia there are no exact maps available and the GIS Lab of at mainly produces the maps used by the international organizations. When maps are available deminers tend to work with the grid of the map being used. It is necessary to convert this local system into Longitude, Latitude. There is a freeware called available. ? There are two different approaches to work with data in GIS: a) Data is entered into a "database" through the GIS. An example is inserting a village through clicking onto the map and then entering the data associated with this village to the point on the map. The GIS is building up its own data structure in the background and the retrieval of this data can then only be done through the GIS. b) The GIS is used for displaying data stored in an external database. The GIS can query (through ODBC, with SQL) the underlying database and retrieve the necessary geographical information (Longitude, Latitude) to display the points on a map. ? When showing our hierarchy of provinces, districts and cities, was skeptical if this is the right way. He fears, that the survey team would not know in which province they are or they cannot know because the borders are not defined and therefore wrong information is saved in the database. ? The discussion with suggested it feasible to build up our own structure for provinces, districts and cities, because we cannot rely upon people defining this structure on a GIS. ? The GIS Lab of the is playing a big role in sharing the collected data. It will probably come to the point when they want to import data gathered through the Field Module and display it on their maps. As long as we're using longitude and latitude, they will surely not face problems working with our data. ? An idea for the Field Module is a cut and paste function of map pieces, into the sketch maps of the minefields (through the clipboard and e.g. paintbrush). The user can then draw the minefield directly on the screen. This might be another approach, compared to