With the attribute data associated with a layer within your map it is possible to ask many questions and have them answered. This can be achieved through the functionality available within desktop GIS. These questions could include relationships between features, also known as objects, within the map layers.
For instance are there objects contained within another object for instance point objects within a polygon object? This information could be used to automatically count all the towns within a county boundary. How many schools within a catchment area and so on. You could also ask questions about when one object crosses another such as where a river (line object), crosses a boundary (polygon object), such as a country border. Another application could be to find out how many objects are within a distance from another object such as a road or river for example. Other examples could include finding where countries share a common border with another country or contain mountains within their borders.
These questions about attribute data and spatial relationships help to show which current features or objects do or do not have certain qualities. Sometimes however it is necessary to create new objects in order to solve specific geographic problems. Objects can be created which meet certain criteria where the relevant attributes are aligned to meet certain predefined conditions. For example this information could be used to find the most suitable place to grow a commodity such as cotton. If you already know the ideal climatic conditions for this commodity you can use this information to build a map containing a new layer showing the most productive regions. By taking various maps containing data on elevation, rainfall, growing season and soils it would be possible to narrow down where the ideal locations could be found. So where all these ideal attributes overlap on your map new features would be created. The new features' boundaries are the areas of overlap which will be different from the boundaries of each of the four features from which it was created. This would then result in a new layer which would then show where cotton could be most successfully grown.
These questions about attribute data and spatial relationships help to show which current features or objects do or do not have certain qualities. Sometimes however it is necessary to create new objects in order to solve specific geographic problems. Objects can be created which meet certain criteria where the relevant attributes are aligned to meet certain predefined conditions. For example this information could be used to find the most suitable place to grow a commodity such as cotton. If you already know the ideal climatic conditions for this commodity you can use this information to build a map containing a new layer showing the most productive regions. By taking various maps containing data on elevation, rainfall, growing season and soils it would be possible to narrow down where the ideal locations could be found. So where all these ideal attributes overlap on your map new features would be created. The new features' boundaries are the areas of overlap which will be different from the boundaries of each of the four features from which it was created. This would then result in a new layer which would then show where cotton could be most successfully grown.
If you would like to further explore how GIS could help your organisation jps services offers one and two day training courses in QGIS, ArcGIS and MapInfo.
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