Question

Based on your textbook readings and the video lecture, discuss the following in a 150-200 words:

1. Name a specific feature of the Earth that is difficult or even impossible to represent perfectly in a GIS, due to it's complexity and detail. The example used in the video lecture was a coastline, which is infinitely complex but is represented in GIS with a series of straight line segments. Your feature can be physical/natural, or human, but do not use the same example (a coastline).

2. Discuss how the feature (from #1) might be represented, using the standard methods that you have seen so far points, lines, polygons, rasters). How would you show the feature in a GIS? What would it look like on your screen in ArcGIS? .

3. Finally, how does your representation of this feature fall short? What real world detail or dynamics are left out by representing the complex feature in GIS? What would the public be left uncertain about it they were to view your representation drawn on a map?

Answer 1

Answer 1) :- Cartographic modelling is a specific feature of the earth that is difficult or even impossible to represent in GIS due to its complexity . example :- the forest cover layer (which are of light green colour ) is at the bottom with the trophic level over it .

2) As in the rasters , the cell typically represents the predominant features or phenomenon of the area covered by a cell whereas vector data can accurately delineate or identify individual features . points data features will become the size of the cell . raster data to point feature using th raster point tool can be used . In vector format a line is an ordered list of x , y coordinates but in raster format it is represented as a spatially connected cells with the same value . Raster data to polyline feature using the raster to polyline tool can be used for conversion . Polygon is an enclosed area defined by ordered list of defined coordinates x and y in which the first and last coordinates are same, thereby representing area . raster data to polygon feature using the polygon raster tool can be used for te conversion .

3)Because of the complex associates with GIS maps its usually best to store the .mxd and all associate GIS files under the single project directory .