GIS Programming

8/3/2019 GIS Programming

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GIS ProgrammingGIS Programming

Why Do We Want to Program GIS?Why Do We Want to Program GIS?

AML AML ± ± ARC Macro Language ARC Macro Language

ArcObject, VBA, COM and Custom Interfaces ArcObject, VBA, COM and Custom Interfaces



Why Do We Want to Program GISWhy Do We Want to Program GIS

Automate repetitive tasks

To present a custom interface for users

Document work Maintain Consistency



AML AML ± ± ARC Macro Language ARC Macro Language

Most often used for scripting repetitive tasks. It

is possible to create a custom interface but this

is now easier with ArcObjects.

It is the command line scripting environment

It is an interpreted language that can be very

slow. Looping is exceptionally slow. Slow for a

computer is still much faster than I can type.



AML Directive AML Directive

AML Directives Begin with an &

± &system Runs an OS Command

± &type Types output ± &do Starts a loop of block of code

± &end Ends a loop or block of code

&do x = 1 &to 100

&if %x% > 50 &then

&do

&type %x%

&end

&end



AML Functions AML Functions

AML functions arc enclosed in []

± [abs ±3] returns 3

± [listfile * -grid] returns all of the grids inthe working dir

± [quote string] places quotation marks

around the quoted or unquoted string

± [open] opens a system file for reading or writing

&setvar fileunit = [open c:\temp\temp outvar ±read]



AML Variables AML Variables

AML variables arc surrounded by %%

± &sv x = %x% + 1 increments x by 1

± AML variables are not typed They can hold Character Strings, Integers, Real

Numbers, and Boolean Expressions

Arc: &sv x = abcdefg

Arc: &ty %x%

abcdefg

Arc: &sv x = 3 + 3

Arc: &ty %x%

6



Watch FilesWatch Files

&WATCH <watch_file> {&APPEND} {&COMMANDS} {&COORDINATES}

Watch files capture the system input an output to a file

Useful for documenting procedures and creating aml

Arc: &watch test

Arc: lc

Workspace C:\GIS_CLASS\GIS_PROGRAMMING does

not exist

Arc: &watch off

Arc: &sys more test

Arc: |> lc <|

Workspace C:\GIS_CLASS\GIS_PROGRAMMING does

not exist

Arc: |> &watch off <|

Arc:



Converting watch files to amlsConverting watch files to amls

Arc: &conv_watch_to_aml test test.aml

Arc: &sys more test.aml

lc&watch off

&r test

Workspace: C:\WORKSPACE\NM_500K

Available Coverages

-------------------

TIC_GEO TIC_LAM



Mosaic.amlMosaic.aml

&args subset /* takes an argument from the command line

&severity &error &ignore /*ignore the errors

&sv list = [listfile %subset%* -file] /* get a list of the files in the dir

&sv count = [token %list% -count] /* count the files to be processed

&ty %count% /* output the count

&do x = 1 &to %count% /* start a loop to extract the dem to grids

&sv name = [extract %x% %list%] /* get the next file

&ty %name% c%x% /* output the file being processed

demlattice %name% c%x% /* arc command to convert to a grid

&end /* end the loop

This part of the aml extracts the DEM files in a directory to a grid



Grid /* starts grid

&sv hw = %count% / 2 /* splits the list into to parts to avoid length problems

&sv hw = [trunc %hw%] /* converts hw to an integer

&sv l1 = c1 /* builds the first half of grids to mosaic

&do x = 2 &to %hw%

&sv l1 = %l1%,c%x%

&end

&ty %l1% /* outputs the first list&sv l2 = c%x% /* builds the list of the second half of the grids to mosaic

&sv z = %hw% + 2

&do x = %z% &to %count%

&sv l2 = %l2%,c%x%

&end

&ty %l2% /* outputs the second list

t1 = mosaic(%l1%) /* mosaic the first list into a single grid

t2 = mosaic(%l2%) /* mosaic the second list into a single grid

m%subset% = mosaic(t1,t2) /* mosaic the two halves into a single gird

Q /* quits gird



kill t1 all /* kill the first half

kill t2 all /* kill the second half

&do x = 1 &to %count% /* start a loop to kill the single girds

kill c%x% all

&end /* end the loop to kill the single grids



Customize the InterfaceCustomize the Interface

Click tools

Select customize

Commands tab

Select the category Pan/Zoom

Drag the tool to a toolbar

These tools will be save in the normal.mxt andwill be present when ArcMap is restarted

To remove a tool drag it off a toolbar

You can make you own toolbar



ArcObjects, VBA, and COM ArcObjects, VBA, and COM

ArcObjects is a collection of COM objectsthat can be used to create customprograms and VBA macros.

ArcGIS Desktop is made from the sameCOM objects.

VBA ± Visual Basic for Applications COM ± Component Object Model is a

Microsoft programming standard



Custom InterfacesCustom Interfaces

You can add and remove tools from

toolbars and create your own toolbars.

You can create custom applications using

the components(ArcObjects) from ArcGIS.



ArcObjects ArcObjects

Introduction to ArcObjects

ArcObjects is the development platform for the ArcGISfamily of applications such as ArcMap, ArcCatalog, andArcScene. The ArcObjects software components expose

the full range of functionality available in ArcInfo andArcView ® to software developers.

ArcObjects is a framework that lets you create domain-specific components from other components. TheArcObjects components collaborate to serve every data

management and map presentation function common tomost GIS applications. ArcObjects provides aninfrastructure for application customization that lets youconcentrate on serving the specific needs of your clients.

From arcobjectsonilne.esri.com



ObjectObject--oriented programming 101oriented programming 101

There are 3 principales that all OOP

languages share.

Encapsulation Inheritance

Polymorphism



InheritanceInheritance

Classes can inherit properties and method from the class they are derivedfrom

If you have a class called pet with the fallowing properties and methods

± Name

± Eat

You can declare a new class that is a type of pet. This class has aditionalproperties.

± DOG:pet

Bark

Eat

You can use the dog object to do the fallowing

± Dim mydog as dog

± Set mydog = new dog

± MYDog.bark; mydog.eat; mydog.name = µREX¶

± myDOG.EAT



PolymorphismPolymorphism

Operators can work differently with

different objects

Dim x, y as integer Dim rex, fluffy as dog

X = 1; y = 2; x+y = 3

Rex + fluffy = puppies



EncapsulationEncapsulation

Encapsulation ± Code, Properties, and

Methods are grouped into groups called

classes. Properties and Methods can be

declared Public or Private.

Public properties and methods can be

used by any code.

Private properties and methods can ONLY

be call from the class in which they exist



Object model diagramsObject model diagrams

Abstract class- you can not create object froman abstract class

Class objects ± you must find another class tocreate an object from a class

Coclass ± you can declare variables of coclass





VBA MacrosVBA Macros

Start the VBA editor by clicking

± Tools

± Macros ± Visual Basic Editor

A Macro is a public subroutine

± PUBLIC SUB MYMACRO()

MSGBOX ³HELLO WORLD´

± END SUB



Macro ExampleMacro ExamplePublic Sub toggle()

Dim pMxDocument As IMxDocument

Set pMxDocument = ThisDocument

Dim pMap As IMap

Set pMap = pMxDocument.FocusMap

Dim player As ILayer

Dim x As Integer

For x = 0 To pMap.LayerCount - 1

Set player = pMap.Layer(x)

If player.Visible = True Then

player.Visible = False

Else

player.Visible = True

End If

Next x

pMxDocument.ActivatedView.Refresh

pMxDocument.ActiveView.ContentsChanged

End Sub











ArcObjects Help ArcObjects Help

http://arcobjectsonline.esri.com

± Getting Started

± Object Model Diagrams

± Samples

Exploring ArcObjects by Michael Zeiller

± PDF is on the cd

Getting to Know ArcObjects by RobertBurke

± Esri Press ISBN 1-58948-018-x

Documents

GIS Programming