Geostatistical_Analyst_Tutorial.pdf

ArcGIS ® 9

ArcGIS Geostatistical Analyst Tutorial

Printed in the United States of America.

The information contained in this document is the exclusive property of ESRI. This work is protected under United States copyright law and other international copyright

treaties and conventions. No part of this work may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying or recording,

or by any information storage or retrieval system, except as expressly permitted in writing by ESRI. All requests should be sent to Attention: Contracts and Legal Services

Manager, ESRI, 380 New York Street, Redlands, CA 92373-8100 USA.

The information contained in this document is subject to change without notice.

DATA CREDITS

ConTRIbuTIng WRITERS

Kevin Johnston, Jay M. Ver Hoef, Konstantin Krivoruchko, Neil Lucas, and Antoni Magri

DATA DISCLAIMER

THE DATA VENDoR(S) INCLUDED IN THIS woRK IS AN INDEPENDENT CoMPANY AND, AS SUCH, ESRI MAKES No gUARANTEES AS To THE qUALITY,

CoMPLETENESS, AND/oR ACCURACY of THE DATA. EVERY EffoRT HAS BEEN MADE To ENSURE THE ACCURACY of THE DATA INCLUDED IN THIS

woRK, BUT THE INfoRMATIoN IS DYNAMIC IN NATURE AND IS SUBJECT To CHANgE wITHoUT NoTICE. ESRI AND THE DATA VENDoR(S) ARE NoT

INVITINg RELIANCE oN THE DATA, AND oNE SHoULD ALwAYS VERIfY ACTUAL DATA AND INfoRMATIoN. ESRI DISCLAIMS ALL oTHER wARRANTIES

oR REPRESENTATIoNS, EITHER ExPRESSED oR IMPLIED, INCLUDINg, BUT NoT LIMITED To, THE IMPLIED wARRANTIES of MERCHANTABILITY

oR fITNESS foR A PARTICULAR PURPoSE. ESRI AND THE DATA VENDoR(S) SHALL ASSUME No LIABILITY foR INDIRECT, SPECIAL, ExEMPLARY,

oR CoNSEqUENTIAL DAMAgES, EVEN If ADVISED of THE PoSSIBILITY THEREof.

u.S. goVERnMEnT RESTRICTED/LIMITED RIgHTS

Any software, documentation, and/or data delivered hereunder is subject to the terms of the License Agreement. In no event shall the U.S. government acquire greater than

RESTRICTED/LIMITED RIgHTS. At a minimum, use, duplication, or disclosure by the U.S. government is subject to restrictions as set forth in fAR §52.227-14 Alternates I,

II, and III (JUN 1987); fAR §52.227-19 (JUN 1987) and/or fAR §12.211/12.212 (Commercial Technical Data/Computer Software); and DfARS §252.227-7015 (NoV 1995)

(Technical Data) and/or DfARS §227.7202 (Computer Software), as applicable. Contractor/Manufacturer is ESRI, 380 New York Street, Redlands, CA 92373-8100 USA.

ESRI, ArcgIS, ArcInfo, ArcCatalog, and ArcMap are trademarks, registered trademarks, or service marks of ESRI in the United States, the European Community, and certain

other jurisdictions.

other companies and products mentioned herein may be trademarks or registered trademarks of their respective trademark owners.

ArcGIS Geostatistical Analyst Tutorial

IN THIS TUTORIAL

With ArcGIS ® Geostatistical Analyst, you can easily create a continuous surface,

or map, from measured sample points stored in a point-feature layer, raster

layer, or by using polygon centroids. The sample points can be measurements

such as elevation, depth to the water table, or levels of pollution, as is the case

in this tutorial. When used in conjunction with ArcMap ™ , Geostatistical Analyst

provides a comprehensive set of tools for creating surfaces that can be used to

visualize, analyze, and understand spatial phenomena.

• Exercise 1: Creating a surface

using default parameters

• Exercise 2: Exploring your data

• Exercise 3: Mapping ozone

concentration

• Exercise 4: Comparing models

Tutorial scenario

• Exercise 5: Mapping the

probability of ozone exceeding a

critical threshold

The U.S. Environmental Protection Agency is

responsible for monitoring atmospheric ozone

concentration in California. Ozone concentration

is measured at monitoring stations throughout the

state. The locations of the stations are shown here.

The concentration levels of ozone are known for

all the stations, but the level for every location

in California is also of interest. However, due to

cost and practicality, monitoring stations cannot

be everywhere. Geostatistical Analyst provides

tools that make the best predictions possible

by examining the relationships between all

the sample points and producing a continuous

surface of ozone concentration, standard errors

(uncertainty) of predictions, and probabilities that

critical values are exceeded.

•Exercise6:Producingtheinal

map

Introduction to this tutorial

Description

ca_outline Outline map of California

ca_ozone_pts Ozone point samples (ppm)

ca_cities Location of major California cities

ca_hillshade A hillshade map of California

The ozone dataset (ca_ozone_pts) represents the 1996 max-

imum eight-hour average concentration of ozone in parts

per million (ppm). The measurements were taken hourly

and grouped into eight-hour blocks. The original data has

been modiied for the purpose of the tutorial and should not

be considered accurate data.

From the ozone point samples (measurements), you will

produce two continuous surfaces (maps), predicting the

values of ozone concentration for every location in the state

of California based on the sample points that you have.

The irst map that you create will simply use all default

options to show you how easy it is to create a surface from

your sample points. The second map that you produce will

allow you to incorporate more of the spatial relationships

that are discovered among the points. When creating this

second map, you will use the exploratory spatial data

analysis (ESDA) tools to examine your data. You will also

be introduced to some of the geostatistical options that you

can use to create a surface such as removing trends and

modeling spatial autocorrelation. By using the ESDA tools

and working with the geostatistical parameters, you will be

able to create a more accurate surface.

Many times, it is not the actual values of some caustic

health risk that is of concern but rather if it is above some

toxic level. If this is the case, immediate action must

be taken. The third surface you create will assess the

probability that a critical ozone threshold value has been

exceeded.

For this tutorial, the critical threshold will be if the

maximum average of ozone goes above 0.12 ppm in any

eight-hour period during the year; then the location should

be closely monitored. You will use Geostatistical Analyst

to predict the probability of values complying with this

standard.

This tutorial is divided into individual tasks that are de-

signed to let you explore the capabilities of Geostatistical

Analyst at your own pace. To get additional help, explore

the ArcMap Help Online system or see Using ArcMap .

• Exercise 1 takes you through accessing Geostatistical

Analyst and the process of creating a surface of ozone

concentration to show you how easy it is to create a

surface using the default parameters.

• Exercise 2 guides you through the process of exploring

your data before you create the surface to spot outliers in

the data and to recognize trends.

• Exercise 3 creates the second surface that considers

more of the spatial relationships discovered in Exercise 2

and improves on the surface you created in Exercise 1.

This exercise also introduces you to some of the basic

concepts of geostatistics.

A rc GISG eoStAtIStIcAl A nAlySt t utorIAl

The data you’ll need for this tutorial is included on the

Geostatistical Analyst installation disk. The datasets were

provided courtesy of the California Air Resources Board.

The datasets are as follows:

Dataset

• Exercise 4 shows you how to compare the results of

the two surfaces that you created in Exercises 1 and 3

to decide which provides the better predictions of the

unknown values.

• Exercise 5 takes you through the process of mapping the

probability that ozone exceeds a critical threshold, thus

creating the third surface.

• Exercise 6 shows you how to present the surfaces you

created in Exercises 3 and 5 for inal display, using

ArcMap functionality.

You will need a few hours of focused time to complete the

tutorial. However, you can also perform the exercises one at

a time if you want, saving your results after each exercise.

A rc GISG eoStAtIStIcAl A nAlySt t utorIAl

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika: