Archive for category: R

Is Moran’s I robust?

4 May, 2012 (12:15) | R, Spatial analysis | By: Manuel Gimond

Moran’s I (both global and local) is a measure of spatial autocorrelation.  One form of its equation looks like this: Note the residual and spread terms. As such, Moran’s I can be sensitive to outliers. The following example demonstrates this point: You can map the simulated data as follows: The p-values from the Monte Carlo […]

A basic transformation and regression example using Census data

9 April, 2012 (12:00) | R | By: Manuel Gimond

The data used in this example are 2010 ACS Census data of per capita income and fraction of population with a Bachelor’s degree or greater. The data file can be downloaded here.

Aggregate census education data (estimate and Margin of Error)

6 April, 2012 (14:03) | R | By: Manuel Gimond

Data for this exercise can be downloaded here: ACS2010.

How N influences the correlation coefficient

6 April, 2012 (11:18) | R | By: Manuel Gimond

R: Compute NDVI from Landsat images

18 February, 2012 (23:44) | R, Remote Sensing, Spatial analysis | By: Manuel Gimond

R: Comparing two marked point patterns

31 January, 2012 (14:56) | R, Spatial analysis | By: Manuel Gimond

R: Does Regression make sense? The area vs. perimeter example

9 November, 2011 (11:47) | R | By: Manuel Gimond

This is an example from the book  Statistics (3rd Edition by Freedman, Pisani and Purves) where the authors remind the reader  “…even if the association [between variables] looks linear… [does] the regression make sense?”.   As an example, they show how the correlation between area and perimeter is strong, yet this regression is “…silly.  The […]

R: K-function

2 November, 2011 (14:32) | R, Spatial analysis | By: Manuel Gimond

The following example assumes a stationary point process. This example does NOT assume a stationary process.

Pearson’s r computed for individual segments of a sample

26 October, 2011 (09:30) | R | By: Manuel Gimond

R: Graphing/Computing Heating Degree Days

11 February, 2011 (10:30) | R | By: Manuel Gimond

You can download data for this example here.