ARCGIS Desktop Spatial Analis.

7/25/2019 ARCGIS Desktop Spatial Analis.

1/34

ESKTOP

Orm

sby Napoleon Burke roess l owden

[ ~ R PRJ


2/34

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Gefting to know ArcGlS desktop

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l.

ArcGlS.

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3/34

ONTENTS

Section

Section

2

Section 3

Ac knowledgmen ts

In

troduct ion xi

ix

Getting to know

GIS

Chapter

Introducing GIS

Chapter 2

Introducing Arc GIS Desktop

3

Getting started

with maps

and

data

apter 3

Exploring

ArcMap

9

Exercise a

Displaying ma p data

Exercise b

Navigating a map

4

Exercise c

l ooking t

fe

ature attributes 4

Chapler

4

Exploring ArcCatalog

53

Exercise 4a

Brows ing ma p data

55

Exercise

4b

Sea rching fo r map data 66

Exercise 4c

Adding data

to

ArcMap

74

Displaying data

Chapter 5 Symbolizing features and rasters 89

Exercise 5a Changi ng symbo l

ogy

92

Exercise 5b Symbo lizing features

by

categorical attributes

Exercise 5c Us i

ng

styles

and

creating

layer

files

xercise d Symbo lizing rasters 2

I


4/34

vi COI/fI

. IlfJ

Chapter

6

Cla ss

ifying

fe

a

tu

res

and

rasters

131

Exercise 6a Classifyi

ng

featu

re

s by sta ndard methods 134

Exercise

6b

Classifyi

ng

f

eat

u

res manua

l ly 145

Exercise c Mapp

in

g

den

sity 154

Exercise

6d Us

i

ng

graduated and chart symbols 161

Chapter 7 Labeling features 175

Exercise 7a Us ing dynamic labels 177

Exercise 7b Setting rules

for

pla cing label s 185

Exercise

7c

Us

i

ng

interacti

ve

l

abel

s

and

creating annotation 196

Section 4

Getting

information

about

features

Chapter

8

Querying

data 203

Exercise

8a

I

den

t ifying selectin

g

finding

and

hyperlinking features 205

Exercise

8b

Selecting features

by

attrib

ute

216

Exercise

e

Creating reports 22 1

Ch

apter 9 Joining

and

relating

ta

bles 229

Exercise 9a Join ing ta bl

es

233

Exercise 9b Re l

at

ing tab l

es

243

Section 5

Analyzing feature

relationships

Chapter 10 Se

lecting features by

lo ca

tion 257

Exercise lOa

Using location queries 259

Exercise

lOb

Combin i

ng

attribute

and

locati

on

queries 265

Chapter

11 Preparing

dat

a for analysis 279

Exercise

11a

Dissolving features 281

Exercise l b Creating

graphs

290

Exercise c Clipping layers 296

Exercise

l d Exp

orti

ng

data 303

Ch

apter

12 Analy

zing spatial da ta 309

Exercise

12a

Bufferi ng fea tu

re

s 312

Ex

ercise 12b Overl

ay

ing data 32 1

Exercise 12c Ca

l

cu

lati

ng

attribute

val

u

es

332

Ch

apter

13 Proj

ecting data

in ArcMap

339

Exercise

13a Pro

jecting

data on

the fly 344

Exercise 13b

Def

in ing

a

prO

jec tion 357


5/34

COl tents

Section

6

Creating

and editing data

Chapter 14 Building geodatabases 367

E xercise 14a Crea t ing a

pe

rsonal geodatabase 37

Exercise

14b

Creating feature classes 377

Exercise

4c

Add

ing fields and

doma

i

ns

384

Chapter

15 Creating features

391

Exercise 5a Draw i

ng

features 394

Exercise 5b Usi ng feature construction tools 401

Chapter 16

Editing features and attributes 415

Exercise

6a Deleting and modifying features 417

Exercise

6b Splitting and

me

rgi ng features 428

E

xercise

16c

Editing feature attribute va l

ues

436

Chapter 17 Geocoding addresses 443

E

xercise

17a

Creating

an

address

locator 446

Exercise J7b Matching

addresses

454

Exercise

17c Rematching

addresse

s

465

Section

7 Presenting data

Chapter

18

Making maps from templates 473

E

xercise

1 Openi ng a map template 475

Exercise IBb Adding x y data to a

map

483

Exercise

IBc Draw

ing graphics

on

a map 489

Chapter 19

Making

maps

for presentation 497

Exercise 98 Layi

ng

ou

t the

page

499

Exercise 19b Add ing a ti t le 5 8

Exercise 19c Add ing a north arrow sca le

bar

and legend

517

Exercise 19d Adding f inal touches and setting print options 526

Section 8 Modeling

Chapter

20 Creating

models

533

Ex

ercise

2 a

Starting a model

536

Exercise 2 b Building a mode l 546

Exercise 2 e En

hancing a

mode

l 557

Appendix A Data l

ice

ns

e agreement 569

Ap pendix B Insta ll ing the data and software 573

Index 579


6/34

Section 5:

nalyzing feature relationships

Chapter 2

nalyzing

spatial

data

uffering features

Overlaying

data

Calculating

attribute

values


7/34

31 ection

:

n lyzingft tu r relationships

Most of the problems you solve with GIS involve comparing spatial relationships among

features- in one layer or in different layers and drawing conclusions. Problem so lving

GIS is called spatial analysis. and it can include eve rything from measuring the distance

between points co modeling the behavior of ecosystems.

The geoprocessing tools in ArcToolbox not only help you prepare data, they also help you

analyze it spatially.

In

this chapter, youll work with twO cools that are very useful in spat

analysi

s:

buffers and overlays.

A buffer is an area drawn at a uniform distance around a feature. It represents a critical zo

such as a floodplain, a protected species habitat,

or

a municipal service area. Features lyin

inside the buffer have a different status from features lying outside the buffer.

A 5 foot buffer around a school defines n re where

billboard advertising is prohibited


8/34

AIIn.0

z illg sp ti

l

t l l l l

Overla

ys

{union and intersect}

id

entify overlaps between features in two layers

nd

create a

dataset in which the lines of overlap define new

fea

ture

s.

In a

union

overlay nonoverlapping

areas are included in

th

e output dataset. A uni

on

dataset then has three types of features:

those found

on

ly in

th

e first input layer {with layer 1 nribme values} those found only in

the second i

nput

layer

{w

ith layer

2

nrib

ute valu

es}

nd

tho

se

created by areas

of

overlap

between the twO layers {with both layer

1

and layer

2

attribute valu

es}

.

In an intersect overlay only the overlapping geometry is preserved

nd

features have attribmes

from both input layers.

Before

overlay

Two

layers each with

one feature

After

union

A

new

layer with

three

features

Av

oc

ad

os

After intersect

A

new

layer with

one feature

A fruit

fly

quarantine zone overlaps

avocado

groves left). Overlay ana

lysis wh t

her

union

or

intersect-creates new

featu

res where inp

ut

layers over lap.

In

this

case

the analys is identifies areas

where avocados must

be

destroyed.


9/34

3 2 Section 5: llalyzillgjetlture relationships

uffering

features

Buffers are created as polygons in a new layer. Buffers can be drawn at a constam distance

for example, 100 meters) around every feature in a layer, or at a distance that varies accordi

to attribute values For example, buffers representing the range

o

rad io signals from trans

mitters might va ry according to an attribute describing the transmitter strength. Buffers ca

also be concentric rings represeming multiple distances. such as the areas within 100, 500

and 1,000 merers o a

well

0

0

j

0

j

0

.

j

j

@ j

0

Constant distance

Variable

distance Mu ltiple

ri

ngs

If features are

lose

together. their buffers may overlap.

You

can preserve the overlaps or

remove them.

Drug F ZDn

_

--

-

Overlaps preserved

Multiple

rings


10/34

llalyzing Jpfltialdata

Exercise 2a

Your goal is co determine the value of h rvestable land in lease F so that your lumber

company can make a bid. In chapter

11

, you dissolved forest stands into leases. Then

you clipped streams and selected goshawk nests within lease

F.

In this exercise, you

ll

buffer the nes t and stream layers to show where logging is prohibited. According to

government reg ulations, no trees may be cut within 8 meters of a goshawk nest, the

range of goshawk fledglings.

Nor

can trees be cut within 5 meters of a stream. Log-

ging near streams leads to erosion of the stream banks, adding sediment co the water.

This kills aquatic plant life and disrupts the food chain. The prohibition on logging s

increased to 100 meters from streams where salmon spawn.

Start ArcMap. In the ArcMap Getting Started dia log box under the

Exi

sting Maps

sec ti

on

, click Browse for more. If ArcMap is already running, c

li

ck the File menu

and

c lick Open.)

Na

vigate to C:\ESRIPress\GTKArcGIS\Chapter12 . Click ex12a.mxd and

c

li

ck Open.

..

..

The map shows lease F, gos

ha

wk nests, and streams.

You

ll begin by buffering the

goshawk nests using the ArcToolbox Buffer tool.

2

On

t

he

Standard l

oo

lbar, click ArcT

oo

l

box

window button

10

ope n ArcToolbox.


11/34

34 5 o i

oIl :

A I I / I ~ I z l l g f e t l l r e rdm i ollShiJJ

3 In the

ArcToo

lb

ox

window, click t

he

plus sign nex t to Analysis Tools. Click the

pl

us sig

next to Pr

ox imity.

Ar< '""Ib".. [ i

IiII

IV

CToabox ~

Ell 30

AnI/yJt

Tools

8

AoIIysIs

T

ools

Ell

.

Extract

.

" """"

-

l I

.$'

~ R h g . l f e r

liI

"

stotlstlts

ill

CwtC9aphy

Tools

onversionToois

iii

Dote

nteroperllbityTools

o . t e ~ T o o I s

Ecblg Tools

iii e o c ~ Tools

e o s t a t i s t l c a I ~ s t

Tools

iii Ref

N'enci"IO Tools

~ T o o I s

iii

NotworkArlllyst

Tools

III

PMCIII

Fabric Tools

.

iii

Sc:t erMtics Tools

III

s.v. Tools

potIeIAnItist Took jY_

Depending on how you sec up your ArcToolbox window (Roacing, tabbed or docked),

yo ur display m y look diffe rem. Also, depending on yo ur ArcGIS license level , yo u m

have more or fewer cools th n the graphic above (which is u

si

ng an ArcView license).

4 Double-click the Buffer tool.

/1,,110 r ' _

:J

x

You

'

ll

select the layer with the input featur

es

to be

buff

ered, d

es

ignate

n output

featur

class, emer a buffer distance,

nd

seiect a dissolve opcion.

5 Click the Input Features drop-down arr

ow

and click NestsF. A lternatively, drag the

NestsF

layer

from the ArcMap table of contents and drop it in th is locatio n. )

6 Click the Browse button next to the Output Feature Class box . In the Ou tput Fea ture

Class

dia log

box,

nav igate to \GTKArcGIS\Chapter12\MyData

and

double-click

MyTongas s.mdb.


12/34

nalyzing s tial data

3

7

In

the Name

box

type NestS f.

Make sure

your dialog

box

matches the following

graphic, then click

Save.

The output feature class information is updated.

=I

lI

I \ S I U P r o s s \ G T \ ( A t c G l S \ O l l o : U f l ~ \ I o f I _ , I I d > ~ 1

8 For the buffer distance, make sure the Linear unit option is selected.

In

the Linear unit

box

type 800.

The neighboring drop-down list shows the type o units which are meters.

I

D I l t . u [ ~ " " C l f I t l l d ]

0 u .

[

~

"

~

~

= = J I ~

9 Scroll down if necessary, click the Dissolve

Type

drop-down arrow

and

click All.

Wherever buffer polygons overlap each other the overlapping boundaries will be dissolved

to make a single feature.


13/34

3 6

Srt rjOll 5:

AlIlllyzillgJenture relationships

10 Click OK

x

When

the Buffer rool finishes process ing. a pop-up notification wi ll appear on the

sys tem tray. C lick the Buffer link in the pop-up notification ro view the Buffer tool

s

results report

.

C U ; I o . . l I u b n O o H : ~

..

:alt1>..t-.. .:_

c:> ' IIIo')pO: "U

c:>

End

'

)pO

:

R Q H )

C : > _ ) pO

:

1U

C :>_Ro I I ( .),

.

-

m

__

~

_ . n . _ c

~ ~ ~ ~

(9 _ n. .:

""".011 Ut.S :lD2D D

C9

_ _ ( l :S , :,

, 2D ,O(D . . - I n . : , .m_

)

When th e operation is completed, close the Results window

The new NestBuf layer is added to the map. Where buffers ove rlap, the barriers betw

them have been removed,

as yo

u specified.

12 If

ne

cessary, change the color of the buffers so they are vis ible against the L

ease

F

ba

ckg

rou nd

.

.

_

.

c "

t>o . o A a

...

5 11.4..

), .

_ U DOlIOI I . , _


14/34

Analyzing patial datil

3 In the table 1 contents right-click the NestBul layer and click

Open

Attribute Table .

The table contains juSt a single record. Buffers created with the dissolve ALL option

form a single feature called a multipart polygon

a

polygon with discontinuous bound-

aries). The attributes are the standard four

for

a geodatabase polygon feature class:

OBJECTID, Shape, Shape_Length, and Shape_Area. Because

o

the dissolve, none o

the NestF layer attributes are passed on to the Output table.

Now

you

ll

buffer the Streams layer. The buffer sizes for this layer wi

ll

va ry according to

whether or not salmon spawn in a stream.

4 Close the Attributes 1 NestBul table.

In

the table of contents right-click the StreamsF

layer and click Open Attribute Tab le .

The HasSpawning field shows whethet Ot not a stream has spawning salmon. The

Distance field values of

5

and 100 correspond to the No and Yes values in the Has-

Spawning field Recall that logging

is

prohibited within 50 meters

o

streams, and

within 100 meters of streams where salmon spawn.)

5 Close the attribute table.

In

the table 1 contents turn

o

the NestBul and NestsF layers.

6

In

the ArcToolbox window double-click the Buffer tool.

17 Click the Input Features drop-down arrow and click StreamsF.

8 Click the Browse button next to the Output Feature Class box. In the Output Feature

Class dialog box navigate to \GTKA r

cGIS\C

haplerI 2\MyData and double-click

MyTDngass .mdb .


15/34

3 8

SUlion 5: nalyzingJeatllre relationships

19 In the Name box type StreamoBuf. Make sure your dialog box matches the following

graphic then click

Save.

..I

20

For

t

he

Buffer distance cli

ck

the Field

op

tion. Click the Fie ld drop-down arrow and

click Distance.

Distance is [he field in [he ScreamsF layer [able that comains the values

5

and 100 .

This time you won t dissolve [he s

tr

eam buffers as you did with th e nest buffer

s.

21 Make sure your dialog

box

matches the following graphic then click OK.

11,, _ ' '

i1

@

0I.tp\.C: fHbIl ClISS

:\ESR.lPreH\GTJ:Ar(:Q5\Chopt.12'\M11Oato\Mv Tnc;tISS .

mclI\5tr

1 ~

DIst.. .ce [voLe or

field]

~ < r i

I ~

FoeId

1

b l

O I aI ~ . I S H l l p I

If

necessa

rY

Iclick the Buffer link in the pop-up notification to see the tool s results repo


16/34

nalyzillg spatial

d to 3

When the operation is completed, the new StreamBuf layer is added

to

the map. t

the current scale, however you cant get a good look

at

the s

tr

eam

buff

ers.

22 Close the Arc

Too

lbox window Click the

Bo

okmarks menu

and

click Streams Closeup.

Now you can see the difference between the 50-meter buffers and the IOO-meter buffers.

23

In

the table of contents right-click the Str

ea

mBuf layer

an

d click

Open

Attribute Tab l

e

In addition to

it

s standard attributes, the output table has attributes from the input

table. (Because you did not dissolve the

buff

ers. the

OUtput

and input tables have the

same numb

er

of reco

rd

there is one buffer for each strea m. This correspondence

makes it possible

to

copy attributes from one table to the other.)

24 Close the attribute tabl

e

Turn o

the StreamsF layer. Turn on t

he

N

es

tBuf

layer In

the

table of contents only the two buffer layers

and

t

he

LeaseF layer

shou

ld

be

turned on.


17/34

32

Section

:

Antllyzi

ng itltllrt

reiatio lShips

In the table of contents right-click the LeaseF layer and click Zoom to Layer

The two buffer layers define the areas within which trees cannot be cut. In the next

exercise, you ll use overlays to define the areas in which they can be cut.

26 If you

wan

t to

save

your work click the File menu and click Save

As

Navigate to

\GTKArcGIS\Chapler12\MyDala. Rename the file my_ex12a.mxd and click Save

7 f you are continuing with the next exercise leave ArcMap open. Otherwise exit the

applicati

on

Click No

if

prompted to

save

your changes.


18/34

Anll yzing splltilll

d fll 3

verlaying

data

A union overlay combines the features in two input laye rs to create a new dataset. In the

following example. one polygon layer represents a land parcel and the other an oil spill. Part

of

the parcel lies outside the spill and part of the spill lies outside the parcel; in the middl

e

the two layers overlap. W hen the laye rs are unioned. the two original polygons b

ec

ome

thr

ee The area

of

overlap becom

es

a new f

ea ture

while the non-overlapping areas become

muhipart polygon s

Parcel

il sp i ll

C ~ ~

ne

po lygon

One polygon

il spill and par

cel

ov

er

lap each othe r

Two po

l

ygo

ns

il spill and pa

rc

el

ove

rl

ap ea

ch

ot

he

r

Two polygon s

Th e oil spi ll and

pa

rcel layers are un ioned to create three new

po

lygons

What kind of attribu

tes

does the un ion layer have? In add ition to its own standard attributes.

it includes all the a

tt r

ibutes of boch input laye r

s

This doesnt mean. however. that every

reco rd h

as

a value for each att ribute. In this exa mple Featu re 1 in the output table has no

Spill_Type value becau

se

it is

out

side the o

il

spill. while Feature 2 has no

w

ner or Landu

se

va

lues because it is outside the parcel. nly Fea ture 3 which spatially coincides wi th both

input la

ye rs has a va lue

for

every attribute.

In

put

t

abl

es

utput table

Th e output table conta ins the ributes of both input layers Output features get the att ri butes

val u

es

of inp ut fea t ures with which th

ey

are spatia lly coincident


19/34

3

Sf nion 5: Ana


20/34

l

ly

z ing spti l d t

Exercise 2b

In this exercise, you ll union the nest and stream buffer layers from the previous exercise

to create a single layer o the land that cannot be harvested. Then you ll union this

layer with a layer o stands in lease

F

Because new features will be created wherever

stand polygons and buffer polygons overlap, every output feature

will

lie

either entirely

inside or entirely outside a buffer. The set o features lying outside buffers represents

harvestable land.

In ArcMap open ex12b.mxd from the C:\ESRIPress\GTKArcGIS\Chapter12 folder.

e

str_

~

i It

0) 11D M o i

5 W 7 1 8 6 I I ~ 1 1 _

The map shows the buffers for streams and goshawk nests. The other l

yers

re turned off.

2 On the Standard toolbar click the ArcToolbox window button.

3 In the ArcToolbox window expand the Analysis

Tool

s if

ne

cessa ry then click the plus

sign next to Overlay

4 Double-cl ick the Union too l

You ll specify the layers to overlay and designate an output feature class.


21/34

3 4

Satioll : Allfllyzillgj( aturl

rritlliollsbips

5 Cl ick the Input

Fe

atures drop-d

own

arrow and click N

es

tSuf.

1 ..

- Ix

C I I C. aI t I rrmnnorts 11 . . . I

The selected

la

yer is added

to

the list of layers that w

il

l be processed in a union .

6 Cl ick the Inpu t Features drop-down arr

ow aga in

and click StreamSuf.

7 Click t

he Sr

o

wse

b

on next to the

Ou

tput Feature Class

box.

In the

Ou

tput F

ea

ture

Class dialog box n

av

igate to IGTKArcGISIChapter121MyData and double-click

MyTon

ga

ss .mdb

.

8 In t

he

Name box t

ype

NoCutArea .

Ma

ke sure your dialog b

ox

matches the following

graphi

c

t

he

n c

li

ck Sa

ve.

-..

1

By default. the

Out

put layer attribute table conta ins i

ts

standard attributes plus the

attributes from

bOth

input laye rs. Optionally. you can omit the input lay

er

identifier

attributes. Alternat ively you can omit all input attributes except the identifiers. This

creates a smaller output table and is convenient if you dont need to work with attribut

(If you l

ater

decide that you do need the input attributes, you can join or relate back t

the input l

aye

r tables using the common identifier attribute.)

Ri ght now, all you need are the identifier attributes .


22/34

nalyzingSp"t;,t datn 3

9 Click the JoinAttributes drop-down arrow

and

click ONLYJID.

You

might have to scroll

down

in

the dialog box to see it.)

1 Make sure your dialog box matches the following graphic, then click OK

hen the operation is completed the NoCutArea layer is added to the map. The new

layer

consisting

of

all buffered areas from the two input layers defines the zone where

no trees may be harvested.


23/34

3 6

ection

5:

A n f l ~ ) z i n g f t ( l l I l r ( relfltiomhips

In the table of contents right-click the NoCutArea

layer and

click

Open

Attribute

Tab

The table contains the four standard polygon feature class attributes (OB]ECTID,

Shape, Shape_Length, and Shape_Area). t also comains the renamed identifier attribu

from the input layers:

FlO

_NestBuf and

FlO

_StreamBuf.

In the exercise introduction, you saw that attributes are

nOt

populated for every record

in a Union attribute table. Identifier attributes, however, are completely populated.

Every record in the Attributes

of

No

Cut

Area has not only an OB]ECTID value, but

also an FID_StreamBuf value and an FID_NestBuf

va

lue regardless of which inpu

feature is spatially coincident with the output feature.

For example, the second record in the NoCutArea table has an

OB]ECTIO

value

of

This va lue is the feature s new identifier. The record s FID_StreamBuf va lue is 10. Th

means that the feature coincides spatially with the feature that has the OB]ECTID

o

10 in the StreamBuf table. The record s FID_NestBuf value is -1. The -1 value means

that the feature does not coincide spatially with any feature in the NestBuf layer. No

tice that the first record has an FID_StreamBuf va lue

of

-1.

This means

that

the featu

does not coincide spatially with any feature in the StreamBuf layer.

Later in this exercise, you will see how to use this information to your advantage.

12 Close the table. Turn on the StandsF layer


24/34

na z ing spatial dntll

3

~ M

-

-

~

_

Cl

EHi l

,

.

.. .: > _ 1:121.1;111

~ _1

1 _ I ~

j

-

..

-

~

.

.

.0_

\ >

.

0_

..

0_

c

0 M

0>_-

(0 )

-

O - A -

lrIIioI

1 1 1.1.6.-

0

- 4 - ;

_.11_.

_

To find the harvestable land you will union the NoCutArea layer with StandsF. After

the

ove rl

ay.

you will be ab

le

to

select

the

polygons

that represent harvestable areas

13 In the ArcToolbox window, double-click the Union tool.

14 Click the Input Features drop-down arrow and click NoCutArea to add it to the list of

input layers.

Do

the same for Stand sF.

15 Click the B

rowse

button

ne

xt to the Output Feature Cla

ss

bo

x.

In the Output Feature

Cl

ass

dial

og box

,

nav

igate to \GTKArcGIS\Chap t

erI2\MyData

and double-click

MyTongass

.

mdb

.

16 In the Name

box

type Final. Make sure your dialog box matches the following graphic,

then click Save .

, Nestsf

Li l


25/34

3 8 S ~ ( / i o l l 5:

A n a l y z i n g f t l l l l l r ~ relationships

Leave the Join Attributes drop-down

li

st set to ALL. This

tim

e you will include a

ll

input attributes in the Union laye

r.

(You wi

ll

need an ribu tes like StandVa lue and

Va luePerMeter

co

recalculate the scand va lues in che next exerci se.

17 Make sure your dialog box matches the follow

in

g gra phic then click

OK

.

--

II

3

. il1

1:::-

' ;tJ

. I

. I

F

I I iI

-

'"'

- ~

8

' - _ , , ,

J

~ I L

.....

1

W hen

th

e operation is completed.

th

e Final layer. wh

ic

h has more than 5,000 feature

is added to the map.

' [dt

Cl e

iii 13 if J

)( ... ... -: >

.

1:1;zt.121

.

-

...

.

..

.

_

At this scale, it's hard to te

ll

if yo u'

re

looking at

th

e result of a spatial anal

ys

is or JUSt

a plate of spagheni.

In

a mome

nt

, you'll zoom in, but first you'll l

ook at th

e

attr

ibute

table of the Final l

aye r.


26/34

nalyzing sptltial data 3

8 In the table of contents right-click the Final layer and cli

ck

Open Attribute Tab le

I

,

The FID_NoCut rea attribute is the renamed OBJECTID from the NoCut rea

layer.

f

a record has a value other chan

-1

in this field

it

means the output feature coin

cides spatially with a buffer feature; in other words it s not harvestable. f a record has

the value -1 it means the output feature does not coincide with a buffer and therefore

is harvestable.

The harvestable area of lease

F,

therefore is the area composed of all polygons in the

Final layer that

have

the value \ in the FID_NoCut rea field

9

lose the Attributes of Final table. lose ArcToolbox.

In

the table of contents turn off

all layers except Final.

20

Click the Bookmarks menu

and

click Close-up.


27/34

33

5:

lUzly

zi

ug Jeature r

lationships

To see which areas can be harvested you will turn on labels.

2 In the table of contents , double-click the Fi

na

l l

ay

er.

On

the Layer Propert i

es

dialog

bo

x, click t

he

Labels ta

b. Che

ck the Label features in this l

aye

r check box. Click

the Label Field drop-down arrow and click FID_NoCutArea. Make sure your dialog bo

matches the follow ing graphic then click

OK

.

- --

_

-

_._ .....-

E t

_

-

___

._-

3

1

__

~

I l..... ...._ 1 ....__ t

On

[he map polygons labeled 1 represem harves[ab le areas.


28/34

nalyzing spatial dflla 3

t would be easier to read the map i you used colors instead aflabels. Applying symbology

is not part o this exercise but you are welcome to do it on your own using what you

learned in chapter 5. Your result might look like this:

Ot

~

~

D -

D

0

_

0 1

0

o

.

In the next exercise you will recalculate the Final layer s 5tandValue attribute to get

an accurate total value

far

harvestable land.

22 If you want to

save

you r

wo

rk, save it as my_ex12b.mxd in the \GTKArcGIS\Chapler12

\MyDala folder.

23 If you

are

continuing with the next exercise, leave ArcMap open. Otherwise, exit the

application. Click o if prompted to save your changes.


29/34

33

S l iOll

5: Analyzillgftature relationships

alculating attribute values

You can write an ex press ion to calculate attribute va lu

es

for all records in a table or juSt fo

s

el

ected ones. For numeric attributes, the expression can include constants, fun

ct

ions, or

values from other fields in

th

e table. Fo r text attributes,

th

e expression can include charac

str in

gs

that you type or text va lues from other fields.

Exercise 2c

The graph you made in chapter showed the timber va lue

of

lease F to be about 1.5

billion dollars. In this exercise yo ull adjust that va lue

to

take into accou nt only harve

able areas. You ll create a definition query to dis

pl

ay these areas, then you ll recalculate

stand valu

es to

determine how much the total harvesta

bl

e area

is

worth.

In ArcMa

p

open ex12c.mxd from the C:\ESRIPress\GTKArcGIS\Chapter12 folder.

The map contains the Final layer you created in the last exercise.

In the previ

ou

s exercise, you s

aw

that

harvestable areas have the value

-1

in the

FID_NoCut rea field. Using that va lue, you will create a definition query

to

displ

ay

only the harvestable areas.

2

In

the table of contents double click the

Fin

al laye r. In the La

ye

r Propert ies dialog b

click the Defini tion Query t

ab.


30/34

3 Cl ick Query Builder to open the Query Builder dialog

box

8 i


31/34

4 Sut ioll

:

A n ( 1 l y z i n g f t a t l l r ~ re Iltiomhips

5 Click OK

on

the Layer Properties dialog

box.

On the

map

only

features

satisfying

the query

are

displayed.

The

layer

attribute table

will show only the records corresponding to

these

features.

Now

you

'll

update

the

StandValue

attribute

for

these

features.

6 In the table of contents, right-click the Final layer and click

Open

Attribute

Table

.

-

---

- ~

-

1___

, ..... ..

.

-

~ - E '

=

:=

:; =

L :==

::

=

:r

:

-

-=

-.-

..

*

- -.-

_ --.----

.

,

.

.

I

.. >n.-. .o)

The table shows 372 records rather than the original 5,439.

The values in the StandValue field need

to

be updated. Although some o the original

stand

polygons

were preserved

intact

in

the Final layer (and still have correct

stand

value

many other stands all

tho

se chat

wer

e overlapped

by

a nest or

stream

buffer-

were

split in the last overlay.

The

resulting smaller polygons have correct area values because

ArcMap

automatically

update

s

che

Shap

e_Area attribute,

but

cheir

s

tand values

which

were simply copied over from

the

StandsF table ,

are wrong.

To c

orrect

the stand

value

you will multiply the

area of

each feature by

its

value per meter.

7 Right-click the field

name

StandValue

and

click Field Calculator. If necessary, click

Y

on the

message

warning

you

that

you

cannot undo the

ca

lculation.

The Field Calculator dialog box opens.


32/34

Analyzing spatial data

8 In the Fields box, double-click Shape_Area to add it to the expression box. Click the

multiplication

(')

button.

Again in

the Fields

box,

double-click ValuePerMeter.

-

.

0 _

-

-

-

.

.

o

.

0 _

:B

-

0 _

.

-

.

o_

~

.

~

.

)

1 : l 1 D ~ 1 J 1 J 1 J

1- -

:1

ElI ...... I

I_

I ~

_

..

_ _

EJ l

c...o

l

This

expression will

give you

the updated

stand

values in dollars. In the table, however,

the stand values are expressed in millions ofdollars.

9 Click at the beginning of the expression

and

type

an

opening parenthesis

(

followed

by a space. Click at the

end

of the expression

and

type a space followed

by

a closing

parenthesis ) . Click the division ( / ) button.

Type

a space

and

type

1000000. Make

sure your expression matches the one

in

the following graphic, then click

OK

.

([Sho ..JItMl- [V J/l oo:KXX

The

values in the StandValue field are recalculated


33/34

6 Secrirm

5:

A

ll

tll ,zlllgjetlt ll} e reltltiom/lips

10 Right-click the StandValue field name and click Statistics

' I.,I IU, I 1..,01

StatiItie

Cart

'

Mrirun: 0.013003

MMrvn:ll .l ll355

Simi: 1052 D8379

Mean 2 928182

Stand vd

DeWotian:

2 078342

...

1

50

30

20

10

Fr

equen y

DlSlr lbul10n

0.0

1.

' .2

U

..

'. 1 ' .1

The sum of the value, i, 1,052 .08379. The harvestable value of lease F

is

therefore just

over a billion

dollars-about

two

thirds

of

the

original calculati

on

s

hown

in yo

ur

gra

from exercise b, step 9.

Close

the Stat istics window

and

the table.

Your company wi

ll

use

thi

s information m

make

a

competi

tive bid. It

s

a big investme

but tr

ee harvesting

is

expensive. You have

to

move heavy

equipment

into

the

area, supp

the labor force. a

nd

construct roads .

A

mor

e detailed ana lysis would consider

ad

ditional facmrs, such

as

the locations of existi

roads, the slope of th e land. and other protected areas like stands of old-growth trees.

12

If

you

want to

save

your work

save

it

as

mL ex

12c

.mxd

in

the \GTKArcGIS\ChaplerI2

\

MyD

ala folder.

In the next chapter, you'

ll

launch

ArcMap

from ArcCaralog. So even

if

you are continui

you should exit

ArcMap

now.

13 Close

ArcMap.

Cl

ick

No

if prompted

10 save

your changes.


34/34

Al fdyzillg spatial

d ftl

Building a

spatial

model

In chapters 11 and 12, you carried out many spatial ana l

ys

is operat ions, such

as

Dis

solve

Cl

i

p

Buffer, and Union, using ArcT

oo

lbox . These operations

we

re not ends in

themse l

ves

but steps in a larger analytical process. Before undertaking a similarly

complicated GIS project,

you

might find it useful to draw a flowchart or diagram that

identifies the goal and the analytical steps that l

ea

d to it. What data wi ll you need What

geoprocessing

wi ll

be required? Which outputs wi

ll

become inputs to new operati

ons

In

ArcGIS Desktop 10 ModelBuilder is available to help you do that. ModelBu

il

der pro

vides a design window where spatial analysis operations can be defined, sequentially

connected, and carried out, all with the use of drag-and-drop icons. ModelBui lder is

both a workflow diagramming too l and a processing environment. It keeps track of

the operations tha t you run, their

resu

lts, and their interdependenci

es

. It gives you a

conven ient

way to

bu

il

d a large project from its component parts and run its processes

separately or together. Your model can be changed at any ti

me to

incorporate new data,

add new conditions, or t ry different assumptions best case, worst case, what if .. ).

Chapter 20 in t

hi

s book revisits the Tongass Forest Lease analysis and shows you how

to design and execute the same project in ModelBu

il

der.

;.

H

1 ,,,111 1,,1 111

_ ...,

x

~

H o I p

x ... ... ~ .l :

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