GIS and Remote Sensing Lecture Notes
Introduction


Spatial Data

The attributes of spatial data are of serveral types and some are suited to raster represenatation, and some are suited to vector (after Theobald, 2007).

Choosing the format for continuous vs discrete data types
                            

Vector storage better for discrete and raster for continuous
 

                            

Advantages/Disadvantages

Vector

Raster
  • digitizing or scanner with vectorization
  • less data storage volume
  • greater boundary precision
  • complex analyses are easier
  • "overlays" rapidly increase complexity and data storage needs
  • substantially easier manipulation
  • scanner/remote sensing acquisition
  • higher data storage requirements (8-32 bytes per cell* rows* columns), but compression (run length encoding, quad trees) helps,
  • decreased boundary precision,
  • no increase in complexity with son and daughter maps

 

 

Demo in ArcGIS

1.      Open the ArcMap document grid_v_poly.mxd

2.      change the transparency of the top layer, or swipe it away

3.      here the grid cell size is 200 m

 


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author: harbord@wlu.edu