Technical Workshop
2016 Esri International User ConferenceSan Diego, California
ArcGIS Geostatistical Analyst
An Introduction
Steve Lynch and Eric Krause
Redlands, CA
Sessions of note…
Tuesday
• ArcGIS Geostatistical Analyst - An Introduction 8:30-9:45 Room 14 A
• Concepts and Applications of Kriging 10:15-11:30 Room 15 A
• Creating Surfaces from Various Data Sources 1:30-2:45 Room 10
• EBK – Robust Kriging as a Geoprocessing Tool 5:30-6:15 Demo theater
Wednesday
• Geostat. Simulations - Preparing for Worst Case Scenarios 11:30-12:15 Demo theater
• ArcGIS Geostatistical Analyst - An Introduction 1:30-2:45 Room 15 B
• Concepts and Applications of Kriging 3:15-4:30 Sapphire I/J
Thursday
• Regression kriging… 8:30-9:45 Room 17B
• Surface Interpolation in ArcGIS 10:30-11:15 Demo theater
• Polygon-to-Polygon Predictions using Areal Interpolation 11:30-12:15 Demo theater
• Regression kriging… 1:30-2:45 Sapphire I/J
• Creating Surfaces from Various Data Sources 3:15-4:30 Room 16 A
ArcGIS Geostatistical Analyst - An Introduction
• What is
• geostatistics?
• Geostatistical Analyst?
• What is new?
• Interpolation workflow
• Demonstrations
• Supplementary information
• Questions / Answers
Outline
What is geostatistics ?
Range
Sill
Nugget
The statistics of spatially correlated data
Semivariogram
ArcGIS Geostatistical Analyst - An Introduction
Semivariogram
Semivariogram(distance h) = 0.5 * average [ (valuei – valuej)2]
ArcGIS Geostatistical Analyst - An Introduction
What is geostatistics ?
The statistics of spatially correlated data
ArcGIS Geostatistical Analyst - An Introduction
ArcGIS Geostatistical Analyst - An Introduction
Geostatistical Analyst - Overview
• Interactive
- Exploratory Spatial Data Analysis tools
- Variography
- Kriging
- Other interpolation methods
- Cross validation
• Geoprocessing toolbox
- Interpolation
- Conversion…
Where is Geostatistical Analyst used?
ArcGIS Geostatistical Analyst - An Introduction
Where is Geostatistical Analyst used?
ArcGIS Geostatistical Analyst - An Introduction
• 12 independent reputable geostatisticians
• Given the same data
• Asked to perform the same straightforward estimation
• Results were widely different
• Different
- data analysis conclusions
- variogram models and choice of kriging type
- searching neighborhoods.
Experiment conducted by the US EPA 25 years ago
Isaaks & Srivastava, 1989. An Introduction to Applied Geostatistics.
ArcGIS Geostatistical Analyst - An Introduction
Geostatistical Analyst – Toolbar and Toolbox
ArcGIS Geostatistical Analyst - An Introduction
Demonstration
Geostatistical Wizard
What’s new in 10 – Optimize buttons
• Kriging
- Nugget, partial sill and other(s), are optimized using cross validation
with focus on the estimation of the range parameter.
What’s new in 10.3 – EBK Chordal distance
ArcGIS Geostatistical Analyst - An Introduction
ArcGIS Geostatistical Analyst - An Introduction
Arctic Circle
Seamless global interpolation
ArcGIS Geostatistical Analyst - An Introduction
Interpolation workflow• Exploratory Spatial Data Analysis (ESDA)
• Interpolate
- estimation of values at unsampled locations based on known values
• Goodness of fit
ArcGIS Geostatistical Analyst - An Introduction
Exploratory Spatial Data Analysis
• Where is the data located?
• What are the values at the data points?
• How does the location of a point relate to its value?
Exploratory Spatial Data Analysis (ESDA)
ArcGIS Geostatistical Analyst - An Introduction
Exploratory Spatial Data Analysis (ESDA)
ArcGIS Geostatistical Analyst - An Introduction
Kriging
• Concepts and Applications of Kriging- Tuesday 10:15 AM - 11:30 AM Room 15 A
- Wednesday 3:15 PM - 4:30 PM Sapphire Ballroom I/J
Outline
• Introduction to kriging
• Best practices
• Fitting a proper model
• Variography, transformations, isotropy, stationarity
• Comparing models using cross validation
• Interpreting results
ArcGIS Geostatistical Analyst - An Introduction
And …Tuesday
• Concepts and Applications of Kriging 10:15-11:30 Room 15 A
• EBK – Robust Kriging as a Geoprocessing Tool 5:30-6:15 Demo theater
Wednesday
• Concepts and Applications of Kriging 3:15-4:30 Sapphire I/J
Thursday
• Regression kriging… 8:30-9:45 Room 17B
• Regression kriging… 1:30-2:45 Sapphire I/J
And…
What is kriging?
• It is a geostatistical interpolation technique
• that models the spatial correlation of point measurements
• to estimate values at unmeasured locations.
• Associates uncertainty with the predictions
Distance
Co
rrela
tio
n
ArcGIS Geostatistical Analyst - An Introduction
Demonstration
Kriging
Empirical Bayesian Kriging (EBK)
• automates the most difficult aspects of building a valid
kriging model
• estimates the semivariogram through repeated simulations
• can handle non-stationary input data.
Unlike other kriging methods (use weighted least squares), the semivariogram parameters in EBK are estimated using restricted maximum likelihood (REML).
New in ArcGIS 10.1
ArcGIS Geostatistical Analyst - An Introduction
Empirical Bayesian Kriging (cont)
• Advantages
- Requires minimal interactive modeling
- Allows accurate predictions of non-stationary data
- More accurate than other kriging methods for small datasets
- Uses chordal distances if data are in GCS (in 10.3+)
- Geoprocessing tool
• Disadvantages
- Processing is slower than other kriging methods.
- Cokriging and anisotropy are unavailable.
ArcGIS Geostatistical Analyst - An Introduction
Demonstration
Empirical Bayesian Kriging
What’s new in ArcGIS Pro 1.2 – EBK Regression Prediction
• It uses EBK
• with explanatory rasters
• that are transformed into their principal components
• these are then used as the explanatory variables in the regression model
• which solves the problem of multicollinearity
+
Demonstration
EBK Regression Prediction
Goodness of fit / Model acceptance
• Subset Features
• Cross Validation
ArcGIS Geostatistical Analyst - An Introduction
Cressie, 1990
• Cross validation does not prove that the model is correct,
• merely that it is not grossly incorrect.
Geostatistical layer
• Method and parameters
• Pointer to the data
• Dynamic
Demonstration
Geostatistical layer
Output = Prediction, Standard error, Probability, Quantile, Condition number
ArcGIS Geostatistical Analyst - An Introduction
What’s new in ArcGIS Pro 1.2 – GALayerToRasters
reaggregation of data from one set of polygons to
another set of polygons
ArcGIS Geostatistical Analyst - An Introduction
Areal Interpolation
ArcGIS Geostatistical Analyst - An Introduction
Performing Polygon-to-Polygon Predictions
Using Areal InterpolationThursday 11:30am – 12:15am
Demo theater
Demo theater
N = 8N = 100N = 500
Simple kriging
ArcGIS Geostatistical Analyst - An Introduction
Geostatistical Simulations: Preparing for Worst Case Scenarios
Wednesday 11:30pm – 12:15pmDemo theater
Demo theater
Interpolation with Barriers
• Kernel interpolation
• Diffusion interpolation
?
Cost RasterArcGIS Geostatistical Analyst - An Introduction
desktop.arcgis.com
ArcGIS Geostatistical Analyst - An Introduction
• Automating geostatistical interpolation using template layers
• Understanding Geostatistical Analyst Layers
• Areal Interpolation
• Empirical Bayesian Kriging
• Dealing with extreme values in kriging
• Finding locations for new monitoring sites using the Densify Sampling
Network tool
ArcGIS Geostatistical Analyst - An Introduction
Interpolation
What are we working on…
ArcGIS Geostatistical Analyst - An Introduction
• ArcGIS Pro• Interactive variography
• ESDA tools
• Explanatory regression kriging
ArcGIS Geostatistical Analyst - An Introduction