地理信息系統(tǒng)gisppt課件-在線瀏覽
2025-06-29 13:55本頁面
【正文】 e + data.... 5. The significance of scale 6. Basic functions of GIS Geographical Information System GIS Any successful example of GIS is based on two fundamental ponents: ? the map data。 and ? the puter software to perform calculations and analysis. Geographical Information System GIS There are many different anisations producing data for use in GIS。 and ? bining two or more datasets together is only appropriate if they have an equivalent scale of capture. Scale of capture Geographical Information System GIS Generalisation The mapping that most of us recognise has been deliberately simplified. Geographical Information System GIS Generalisation The mapping that most of us recognise has been deliberately simplified. Geographical Information System GIS Generalisation The mapping that most of us recognise has been deliberately simplified. Geographical Information System GIS Generalisation The mapping that most of us recognise has been deliberately simplified. Geographical Information System GIS Generalisation The mapping that most of us recognise has been deliberately simplified. ?largescale data when viewed at a small scale (zoomed out), appears cluttered whereas smallscale data when viewed at a large scale (zoomed in), appears very sparse. ?A cartographer creates these simple, readable maps by selecting information from a largerscale source. Not all the detail from the source map can be shown. Geographical Information System GIS Generalisation Sometimes it may be necessary to alter a feature’s true survey position slightly to make space for the map symbols. Furthermore, the thick red lines of an A road are shown much wider on the map than the actual road is on the ground. This science of smallscale map production is known as generalisation. Geographical Information System GIS Generalisation Geographical Information System GIS Be careful with scale ? Many GIS data products are created from generalised map sources ? The effects of generalisation will show up if this data is viewed against other more largescale mapping. Geographical Information System GIS Be careful with scale The generalised data is not wrong, it is just being magnified more than was ever intended. When you zoom in, the deviation of the simplified features from their survey position is apparent when the largescale data bees visible. Geographical Information System GIS Introduction 1. What is GIS? 2. In the beginning.... there were maps 3. Introducing raster and vector 4. GIS = software + data.... a formula for success 5. The significance of scale 6. Basic functions of GIS Geographical Information System GIS Basic functions of GIS? Geographical Information System GIS Some examples of GIS in Action: Land Use Planning Geographical Information System GIS Some examples of GIS in Action: Monitoring of deforestation Source: UC Berkeley GIS Center Geographical Information System GIS Some examples of GIS in Action: Find the least cost bike route (in terms of traffic and slope) from and to two user defined points Geographical Information System GIS Some examples of GIS in Action: 3 D Visualization and Terrain Analysis for transportation planning Watershed delineation using digital elevation models Geographical Information System GIS Some examples of GIS in Action: Source: Geonmonics, Inc. Geographical Information System GIS Some examples of GIS in Action: Site
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