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Surface water body data like Lakes, Ponds, Reservoirs, Rivers are important geospatial data for many purposes. This kind of data can be obtained in many ways. They can come from field measurements, GPS-based measurements, or derived from Aerial Photographs or Satellite Imagery. Deriving surface water features from aerial photographs or satellite imagery, in particular, has some strength compared to more conventional mapping methods. Aerial Photographs or Satellite Imagery recording the surface water body in a synoptic way. It s is basically just like the real features that we saw in the field. It is also efficient and time-saving. You can get the data either in vector format or raster format depends on your preferred extraction methods.  Particularly for satellite imagery, these data could come from a wide range of imaging sensors operates in different electromagnetic spectrum (from optical spectrum to radar/microwave spectrum). Different spectrums will expose different characteris...

CAD and GIS are both technology related to mapping and spatial dimensions of earth surface objects. CAD mainly is used in the Architecture or civil engineering domain (microscale) and GIS is used for spatial analysis at the landscape/regional level. Both of the technology are using spatial representation in vector graphics structures. The format for these vector data is various, but DWG is a major format in CAD since decades ago, and Shapefile/SHP is the major and most used spatial data format in GIS for at least since the nineties.  Because both of them are using vector graphics, straight conversion between two mainstream formats is absolutely possible. Modern CAD software mostly supports direct reading of SHP format and vice versa. CAD also has point representation, polyline representation, and polygon representation as well as Shapefile GIS format. There are no many differences between those two formats. The only difference is CAD DWG format usually didn't store tabular informat...