Geogrpahic Data Flashcards
Spatial dependency
The manifestation of toblers first law of geography, by which variance increases with distance in characteristic ways
What is the first step before analysis?
We need to measure the expected degree of dependency amount nearby observations
What is spatial heterogeneity?
Tendency of spatial data to exhibit spatial non-stationarity I.e the change of local statistical parameters with location makes identifying representative samples difficult
Types of stratified sampling
Stratified sampling - sampling in regular grid pattern
Stratified random sampling - sampling randomly within gridded space
Stratified sampling with random variation in grid spacing
Other types of sampling
Clustered sampling - sampling only in certain grid spaces
Transect samplibn - sampling multiple points along a transect
Contour sampling - sampling at multiple points along a contour
What May effect simple random sampling
Strategy at be affected by outliers
What may affect stratified random sampling ?
Strategy may be effected by periodicity
What are the three types of distance decay
Linear distance decay
Negative power distance decay
Negative exponential distance decay
What is spatial resolution
The smallest feature that can be detected I.e. the pixel size
Temporal resolution
Smallest time interval between a repeated observation
Spectral resolution
Number, position and width of spectral bands
Radiometric resolution
Small distinguishable differences in radiation and magnitude
What is the difference between autocorrelation and smcross correlation
In contrast to autocorrelation, cross correlation compares different variables
What spatial statistic technique
Moran’s I
How do we interpolate for objects
Use local neighbourhood data to estimate a value at an I sampled location (I.e closest number if point nys or within a given search radius)
Can also use the entire dataset toto estimate a value at an unsnapped location
