Geospatial Data

 


From the photo above, there are two types of geospatial data: spatial data and attribute data. 

Spatial data: any type of data that can be linked to a specific location or geographic area.
Attribute data: includes a wide range of information that describes characteristics of spatial features.

There are two types of spatial data: vector data and raster data.

  • Vector data can be represented by points, lines, and polygons. 
           Points represent individual locations or features, such as wells, benchmarks, and gravel.
           Lines represent linear features, such as roads, rivers, contour lines, and pipelines.
           Polygons represent areas, such as the boundaries of a city, a park, water bodies, or a land parcel.
  • Raster data are represented as a grid of cells, where each cell is called a pixel and represents a measurement or observation of a specific variable at a particular location on the Earth's surface.  It is divided into rows and columns. 

  • Element of the raster data model :
           1) Cell Value - can be categorical or numeric.
           2) Cell Size - the size of a single pixel which may determine the spatial solution.
           3) Raster Bands - each band representing a different variable or aspect of the data. 
           4) Spatial Reference - information that can align with other data.



Data Conversion
Rasterization: Vector data --> Raster data 
Vectorization: Raster data --> Vector data

Comparision between vector data model and raster data model

Attribute data describes characteristics of spatial features and is mostly organized in tables.

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