Question 7: Transformations

Question 7

What transformations are more tricky than others?

Transformations from one measurement framework to another involve one of these cases:

Extraction from a covering data structure
Require addition of spatial information (neighborhoods)
Require addition of attribute information (rules of combination)
Both 2 and 3

Transformations appear in many roles, often called other things. Sometimes they are assumptions or preprocessing steps without any access to the controls. Other times, the user has a lot of decisions to make. The terminology used for each approach is dissimilar from the others, so it is often hard to translate the meaning.

In response to this question, pick at least one of the options below:

Say you have access to two coverages, one raster and one vector polygons. The raster cells are 30 meters, the polygons are described as 10 hectare minimum mapping unit with 10 meters positional accuracy. Does this tell you anything about how to combine (overlay?) these two sources? What more do you need to know?
Exploring GIS uses interpolation as the core example for transformations. Revisit Exercise 6 from the 460 class and discuss the assumptions involved in that process. Consider what extra information is used in making rainfall maps.
Pick two forms of data and figure out how hard it would be to convert one into the other or viceversa.

Your answers shouldn't be much longer than one page.