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Arc Objects
Arc Objects is the development platform for the
ArcGIS family of applications such as Arc Map, Arc
Catalog, and Arc Scene.
Arc Objects is a framework that lets you create
domain-specific components from other components.
Arc Objects provides an infrastructure for
application customization that lets you concentrate on
serving the specific needs of your clients.
ARCOBJECTS AND THE ARCGIS
DESKTOP
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ArcObjects is the development platform for Arc
GIS Desktop.
The Arc GIS Desktop systems each contain a
configuration of applications,such as Arc Catalog,
Arc Map, Arc Toolbox, and Arc Scene, and can
host a variety of extension products such as
ArcGIS Spatial Analyst,ArcGIS Geostatistical
Analyst, ArcGIS 3D Analyst and others.
Arc Map , Arc Catalog
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Arc Map is used for mapping and editing tasks as
well as map-based analysis.
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Arc Catalog is used for managing your spatial
data holdings, defining your geographic data
custom schemas, and recording and viewing
metadata.
ARCOBJECTS FRAMEWORK
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Arc Objects is built using Microsoft’s Component
Object Model (COM) technology.
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It is possible to extend Arc Objects by writing
COM components using any COM-compliant
development language.
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You can extend every part of the Arc Objects
architecture in exactly the same way as ESRI
developers do.
Interpreting object model
diagrams
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Arc Objects object model diagrams are based on
the UML notation, an industry-diagramming
standard for object-oriented analysis and design.
The development environment,Visual Basic
or other, lists all of the many classes and
members but does not show the structure of
those classes.
These diagrams complete your
understanding of the Arc Objects
components.
Classes and objects
There are 3 types of classes shown in the UML diagrams
—abstract classes, co classes, and classes.
 A coclass represents objects that you can directly create
using the object declaration syntax in your development
environment. In Visual Basic, this is written with the
Dim pFoo As New FooObject syntax.
 A class cannot directly create new objects, but objects of
a class can be created as a property of another class or by
functions from another class. Eg. FeatureCursor
 An abstract class cannot be used to create new objects,
but it is a specification for subclasses.Eg: “line” could be
an abstract class for “primary line” and “secondary line”
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Type inheritance
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Type inheritance defines specialized
classes that share properties and
methods with the super class and have
additional properties and methods.
Line
Primary Line
Secondary Line
This diagram shows that a primary line (creatable class) and
secondary line (creatable class) are types of a line (abstract
class).
Instantiation
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Instantiation specifies that one object
from one class has a method with which
it creates an object from another class.
Pole
Transformer
A pole object might have a method to create a transformer obje
Customization
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Showing and hiding toolbars using the Customize
dialog box
1. Click the Tools menu and click Customize.
The Customize dialog box appears.
You can also double-click any unoccupied area
of any toolbar to display the Customize dialog box.
2. If it is not visible, click the Toolbars tab.
The presence or absence of a check mark next
to the toolbar name indicates its visible state.
3. Check and uncheck the check boxes.
Creating a new toolbar
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In the Toolbars tab of the Customize dialog box, click
New.
In the dialog box that appears, specify Chapter One
Examples as the name of the new toolbar or use the
default setting.
Store the toolbar in the document by changing the
name of the Save in dropdown list from Normal.mxt to
Untitled or the name of the current project.
Click OK.
The newly created toolbar appears near the top of the
application window.
Adding buttons to a toolbar
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Make sure the toolbar you just created is visible.
If it is not visible, display the Customize dialog box.
Click the Commands tab of the Customize dialog
box.
Select the Pan/Zoom category from the Categories
list.
Scroll to the bottom of the Commands list.
Select the Zoom in command and drag it to the
toolbar. Release the command when the arrow
cursor with a small box below it appears.
Continue adding commands from the Pan/Zoom
category
You may switch to other categories to select
commands.
Renaming a toolbar
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In the Toolbars tab, click the name of the
toolbar whose name you want to change.
Click the Rename button.
In the dialog box that appears, specify My
Own Tools as the new name.
Note that you can only rename toolbars
you’ve created.
Click OK.
If you decide not to rename the toolbar, click
Cancel.
Removing buttons from a toolbar
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Make sure the toolbar you just renamed, My Own
Tools, is visible.
If it is not visible, display the Customize dialog
box.
Drag some of the commands off the toolbar.
Even though you’ve removed the buttons from the
toolbar, they are still available in the Customize
dialog box.
Adding a menu to a toolbar
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Make sure the My Own Tools toolbar is visible.
If it is not visible, display the Customize dialog
box.
Click the Commands tab and choose the Menus
category from the Categories list on the lefthand side of the dialog box.
In the Commands list at the right-hand side of
the dialog box, click Selection.
Drag and drop it to the left of the Zoom In button
on the My Own Tools toolbar.
Click Close in the Customize dialog box.
Click Selection on the My Own Tools toolbar
and note the menu that appears.
Saving changes to a
template
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You can save your work to a document or template.
Changes saved to a document are specific to the
document, whereas changes saved to a template will be
reflected in all documents based on the template.
Click the File menu and click Save As.
Navigate to the Templates folder of the <installation
directory>\bin folder.
Click the Create New Folder button.
Type a new name for the folder and double-click it.
Type the template name, click ArcMap Templates (*.mxt)
from the Save as type dropdown menu, then click Save.
WRITING MACROS IN VBA
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You can use the VBA integrated development
environment to create macros to help you automate
tasks you perform repeatedly or to extend the
application’s built-in functionality.
With the Visual Basic Editor, you can edit macros,
copy macros from one module to another, rename
the modules that store the macros, or rename the
macros.
Creating a macro
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Click the Tools menu, point to Macros, then click Macros.
In the Macros dialog, type name in the Macro name text
box and click Create.
The application creates a new module named Module1
and stubs in the Sub procedure.
Enter some code.
Switch back to ArcMap by clicking the File menu,
clicking Close, and clicking Return to ArcMap.
Click the Tools menu, point to Macros, then click Macros.
Select the Module1. Name macro and click Run.
Adding a macro to a toolbar
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Click the Tools menu and click Customize.
In the Toolbars tab, ensure that the toolbar is visible.
Click the Commands tab and select the Macros category.
Click the name of project in the Save in dropdown menu.
The commands list to the right of the dialog box lists
Project.Module1.Name.
Drag the macro name to the toolbar you created.
The macro appears with a default icon.
To change its properties, right-click the icon.
In the context menu that appears, click Change Button
Image and choose a button from the palette of icons.
Close the Customize dialog box.
Click the button to run the macro.
Calling built-in Commands
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Calling existing commands involves working with the
ArcID module.
Using the Find method, the code locates the unique
identifier (UID) of the command in the ArcID module.
Steps
1. Click the Tools menu, point to Macros, then
click Visual Basic Editor.
2. In the Module1 module, create a Sub
procedure with the following code:
3. Add the macro to a toolbar or menu.
4. Run the macro.
Code for FullExtent
Sub FullExtentPlus()
Dim intAns As Integer
Dim pItem As ICommandItem
With ThisDocument.CommandBars
Set pItem = .Find(ArcID.PanZoom_FullExtent)
pItem.Execute
intAns = MsgBox(“Zoom to previous extent?”, vbYesNo)
If intAns = vbYes Then
Set pItem = .Find(ArcID.PanZoom_ZoomToLastExtentBack)
pItem.Execute
End If
End With
End Sub
Creating a Command in VBA
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Once invoked, a command usually performs some direct
action without user intervention.
A command is a type of UIControl.
Click the Tools menu and click Customize.
In the Customize dialog box, click the Commands tab and
change the Save in dropdown menu to the name of your
project or to Untitled.
In the Categories list, select UIControls.
Click New UIControl.
In the dialog box that appears, choose UIButtonControl as
the UIControl Type, then click Create and Edit.
Adding code for the UIControl
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The application adds an entry in the Object Box for the
UIButtonControl and stubs in an event procedure for the
UIButtonControl’s Click event.
You’ll add code to this event to zoom the display to the
extents of the dataset.
Private Sub UIButtonControl1_Click()
Dim pDoc As IMxDocument
Set pDoc = ThisDocument
pDoc.ActiveView.Extent =pDoc.ActiveView.FullExten
pDoc.ActiveView.Refresh
End Sub
Adding code for the UIControl
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Click the Tools menu, click Customize, then click
the Commands tab.
In the Customize dialog box, click the Commands
tab and change the Save in dropdown menu to the
name of your project or to Untitled.
In the Categories list, choose UIControls and drag
the UIButtonControl you created to a toolbar.
Close the Customize dialog box.
Try the new command by zooming in on the map
and clicking the button.
Creating a tool in VBA
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1. Click the Tools menu and click Customize.
2. Click the Commands tab and change the
Save in combo box to the name of your project
or Untitled.
3. Choose UIControls from the Categories list.
4. Click New UIControl.
5. In the dialog box that appears, choose
UIToolControl as the UIControl Type, then click
Create and Edit.
Changing button properties
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Right-click any toolbar and click Customize in
the context menu that appears. Click the right
mouse button to determine whether a context
menu is available.
Right-click the button whose properties you
want to change.
In the context menu that appears, click
Change Button Image and choose an image.
The image you chose appears on the face of
the button.
Close the Customize dialog box.
Thank you..
Arc Objects Problem Solving Guide
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DEFINE THE ARCOBJECTS PROGRAMMING TASK
1. Describe the problem in Arc Objects terms.
2. Identify subtasks.
3. Decide where to write the code.
4. Search for a related sample or recommended methodology.
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LOCATE THE CORRECT OBJECT MODEL
1. Identify a subtask.
2. Extract keywords.
3. Search for the correct object model diagrams.
4. Review all related documentation.
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NAVIGATE THE OBJECT MODEL DIAGRAM
1. Review the structure of the object model diagram.
Writing Code Using Arc Objects
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In general, there are three ways to write Arc Objects
code:
• As a VBA macro in an ArcGIS application
• As an ActiveX COM component such as a DLL or
OCX
• As a standalone EXE
Writing VBA macros in ArcGIS
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Advantages
• It’s fast and easy to create, test, and debug macros
inside Arc Map and Arc Catalog.
• The standard ESRI type libraries are already
referenced.
• Important global variables, such as the Application
and Document, are available.
• It’s simple to assemble UI forms using VBA and
ActiveX components.
• It’s straightforward to integrate VBA code with new
Arc Objects UIControls.
• It’s relatively easy to migrate VBA code to VB
ActiveX DLL projects.
Writing ActiveX COM components
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Advantages
• They can be easily delivered to end users via custom
setup programs.
• You can hide Arc Objects code in a binary file and
then deliver the functionality to end users with a setup
program.
• You can extend and customize virtually every aspect
of the ArcGIS technology.
Disadvantages
• Have to acquire and use another COMcompliant development tool
• Do not have direct access to the Application and
ThisDocument global variables.
• It is often more difficult to debug the code.
Standalone Applications
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Advantages
• You can use the ESRI Arc Objects Map control to simplify
the embedding of Arc Objects functionality in your
application.
• You can design a highly customized user interface specific
to your application.
• You can quickly create small, lightweight applications.
Disadvantages
• You cannot take advantage of the extensive functionality
that ESRI has built into the existing ArcGIS applications
such as Arc Map or Arc Catalog.
• You cannot use Arc Map documents or templates to
their fullest capacity.
Arc Map Core Objects
Arc Map Document
APPLICATION COCLASS
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The Application object directly manages a collection of
objects, MxDocument, AppDisplay,SelectionEnvironment.
When you first start Arc Map, the Application object is
first created, and then it in turn instantiates all of the
objects it manages.
The IApplication interface provides access to the
MxDocument object, the StatusBar object, the Templates
object, the currently selected tool, the Visual Basic Editor.
The IMxApplication interface provides access to the
remainder of the objects the Application automatically
creates, including AppDisplay,Paper Co Class, Printer,
and SelectionEnvironment. Additionally, IMxApplication
exposes methods for exporting the current map document
or copying it to the system clipboard.
MXDOCUMENT COCLASS
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The Arc Map document is called MxDocument; its role
is to control the representation of data.
The Arc Map application automatically creates this
object when the application first starts.
MxDocument specifically creates and manages the
following objects: an empty Map, a PageLayout, the
TOCCatalogView, the TOCDisplayView.
You can obtain a reference to the MxDocument through
IApplication::Document.
Views
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View is the main application window, or the place
where all data is drawn.
Arc Map currently has two different views,data
view and layout view
Objects implement the IActiveView interface to
establish themselves as views.
The data view corresponds to a Map object,
and the layout view corresponds to the
PageLayout object.
Either of these objects can be set as the
document’s active view, and only one view is
visible at a time.
Checking Type of View
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The following VBA code checks the type of active
view:
Dim pMxDoc As IMxDocument
Set pMxDoc = Application.Document
If TypeOf pMxDoc.ActiveView Is IMap Then
MsgBox "Active View is a Map"
ElseIf TypeOf pMxDoc.ActiveView Is IPageLayout
Then
MsgBox "Active view is the PageLayout"
End If
Application Extensions
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The Application object directly manages the life of
all application extensions.
Application extensions are those extensions
registered in the ESRI MxExtension objects;
All extensions are automatically created and
destroyed in synchronization with an Application
object.
Use the IExtension interface to query the
properties of an extension or implement this
interface to create your own custom extension.
Getting Reference to an Extension
Public Sub CheckEditState()
Dim pEditor As IEditor
Dim pUID As New UID
pUID = "esriCore.Editor"
Set pEditor =
Application.FindExtensionByCLSID(pUID)
If pEditor.EditState = esriStateEditing Then
MsgBox "Active Edit Session Present"
End If
End Sub
TOCDISPLAYVIEW AND
TOCCONTENTSVIEW COCLASSES
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Contents views are tabs in the Arc Map table
of contents.
ArcMap ships with two contents views:
display view and source view.
The Display tab is the TOCDisplayView
object, and the Source tab is the
TOCCatalogView object.
Developers can add new contents views by
creating their own custom object that
implements the IContentsView interface.
MAP COCLASS
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Every map document contains at least one Map
object.
Only one Map can have focus at a time, and this
Map is called the focus map.
IMxDocument provides access to all of the Map
objects loaded in the document;
IMxDocument::FocusMap returns a reference to
the Map currently with focus, and
IMxDocument.Maps returns the entire collection
of Map objects.
MapSurround objects are elements that are
related to a Map. Types of map surrounds include
SELECTIONENVIRONMENT COCLASS
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Controls properties related to creating and drawing
selections.
A SelectionEnvironment object is automatically created
by the Application object when the application starts.
Access to the Application object’s
SelectionEnvironment is through
IMxApplication::SelectionEnvironment.
Change Default Selection Color
Public Sub ChangeDefaultSelectionColor()
Dim pMxDoc As IMxDocument
Dim pMxApp As IMxApplication
Dim pSelectionEnv As ISelectionEnvironment
Dim pRgbColor As IRgbColor
Set pMxApp = Application 'QI
Set pMxDoc = Application.Document
Set pSelectionEnv =
pMxApp.SelectionEnvironment
Set pRgbColor = New RgbColor
pRgbColor.Red = 255
Set pSelectionEnv.DefaultColor = pRgbColor
Display Objects
FEATURE RENDERER
A feature renderer is a method for drawing feature layers.
Use symbols and colors to visually display features, possibly based on one
or more attributes.
Types of feature renderers:
• SimpleRenderer uses the same symbol for each feature.
• ClassBreaksRenderer allows classes of numeric attribute values to be
defined. A different symbol is specified for each class.
• UniqueValueRenderer uses a different symbol for each unique attribute
value.
• ProportionalSymbolRenderer modifies the size of the symbol in proportio
to an attribute from a field.
• DotDensityRenderer displays a scattering of marker symbols in polygon
features, the density of which reflects the value of an attribute.
• ChartRenderer displays pie, bar, or stacked bar charts that are comprised
from one or more attribute fields.
Get a Feature Renderer
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To get to a feature renderer object in Arc Map from a layer, QI to
IGeoFeatureLayer and get the Renderer property.
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A simple renderer is the default renderer object when
a new feature class is loaded.
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' Check if the layer is a feature layer
If Not TypeOf pLayer Is IGeoFeatureLayer Then Exit Sub
Set pGeoFeatureLayer = pLayer
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' Check if there is a simple renderer and get a reference to it
If Not TypeOf pGeoFeatureLayer.Renderer Is ISimpleRenderer
Then Exit Sub
Set pSimpleRenderer = pGeoFeatureLayer.Renderer
Color Objects
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Objects that support the IColor interface allow precise control
over any color used within the ArcObjects model.
You can get and set colors using a variety of standard color
models—RGB, CMYK, HSV, HLS, and Grayscale.
RGBCOLOR COCLASS
To get and set the red,green, and blue components of a color
Interface- IRGBColor
CMYKCOLOR COCLASS
Colors can be specified for output in terms of Cyan,
Magenta, Yellow, and Black.
Interface- ICMYKColor
Symbol Objects
Types of Symbols
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ArcObjects uses three categories of symbols to draw
geographic features:
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Marker symbols,
Line symbols,
Fill symbols.
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Display Objects
Display Objects
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Allow application developers to easily draw graphics on
a variety of output devices.
Allow you to render shapes stored in real-world
coordinates to the screen, the printer, and export files.
Use the IDisplay interface to draw points, lines,
polygons, rectangles,and text on a device.
Access to the display object’s DisplayTransformation
object is provided by this interface.
To Pan Map Display
Private Sub UIToolControl1_MouseDown(ByVal
button As Long, _ByVal shift As Long, ByVal x
As Long, ByVal y As Long)
Dim pScreenDisplay As IScreenDisplay
Dim pActiveView As IActiveView
Dim pMxDoc As IMxDocument
Set pMxDoc = Application.Document
Set pActiveView = pMxDoc.FocusMap
Set pScreenDisplay = pActiveView.ScreenDisplay
pScreenDisplay.TrackPan
End Sub
DISPLAYTRANSFORMATION COCLASS
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Manages the map-to-device transformation
Defines how real-world coordinates are mapped to an
output space.
Map’s DisplayTransformation has a SpatialReference
object that manages the Map’s current coordinate system.
A reference to the SpatialReference object is set
through IDisplayTransformation::SpatialReference.
IDisplayTransformation
To prepare a transform for use, follow these
steps:
1. Set the full map extent with the Bounds
property.
2. Set the visible map extent (zoom rectangle)
with the VisibleBounds property.
3. Set the output area of the device using the
DeviceFrame property.
4. Set the resolution of the output device using
the Resolution property.
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Rubber Band Objects
IRubberBand Interface
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IRubberBand interface, allow the user to digitize geometries
on the display using the mouse—either to create whole new
geometry objects or to update existing ones.
Examples-Dragging an envelope, forming a new polyline,
or moving a point.
IRubberband interface has two methods
TrackExisting
Move existing geometries
TrackNew
Create new geometries
TrackNew method
Private Sub UIToolControl1_MouseDown(ByVal button As
Long, _
ByVal shift As Long, ByVal x As Long, ByVal y As Long)
Dim pRubberLine As IRubberBand
Dim pGeom As IGeometry
Dim pMXDoc As IMxDocument
Set pMXDoc = ThisDocument
Set pRubberLine = New RubberLine
Set pGeom=pRubberLine.TrackNew
pMXDoc.ActiveView.ScreenDisplay, Nothing)
End Sub