arcgis geostatistical analyst: an introduction · sessions of note… tuesday • arcgis...

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