Pg 1 of 30 AGI Application Programming using the STK Object Model Sylvain Dupont & Alan Ocampo Analytical Graphics, Inc October 2005

Pg 1 of 30AGI www.agiuc.com

Application Programming using the STK Object Model

Sylvain Dupont & Alan OcampoAnalytical Graphics, Inc

October 2005


Our goal

• Make it easier for integrators to reuse AGI technology– Reliance on industry standards– Shorter learning curve & development cycle


History

Connect• TCP/IP socket• String based language

6.05.0 7.0 …5.04.0…

Plugin scriptsScripting languages only(perl, VBScript & matlab)

Application Object Model

• Control STK windows• ExecuteCommandInternal HTML Viewer• Window.external

STK/X – 4DX• Map & globe controls• ExecuteCommand

STK PluginsCOM based plugins

STK Objects Library• Manipulate the STK objects• Available with STK, STK/X & 4DX• Data providers


STK Objects Library - Technology

• Based on COM (Component Object Model)

• Available development environments– .Net (C#, Visual Basic .Net)– Java– C++– Visual Basic 6– Scripting languages


Scope for STK 7

• First release covers:

(~ PRO & AVO licenses)

• 484 interfaces, 2019 properties, 214 methods

• Coverage will increase with subsequent releases

• Fall back to Connect for capabilities not yet supported


Example: Target object


Benefits

• Better development tools support

– Errors detected at compile time– Rich exception information provided at run-time

• Less code to write for 3rd party developers– Avoid tedious string parsing & formatting


Next…

• How to perform the most common Connect tasks with the STK Object Model


Agenda

• Life before the API: Connect

• What is the STK Object Model API?

• Features

• Basics of application development (using VB6)

• Benefits and Limitations

• Recommendations


Life Before the API : Connect Revisited

• What is ‘Connect’?– Connect is the ‘language’ of STK.– You can send Connect commands to STK via TCP/IP or COM

• Sample code using Connect (via COM)

‘m_stkApp is an instance of an STK/X application object

‘Load a scenariom_stkApp.ExecuteCommand "Load / Scenario """ & “c:\temp\scenario.sc”

& """"

‘get a string containing a list of all object pathsDim result As AgExecCmdResultDim instanceNames As StringDim objectList() As String Set result = m_stkApp.ExecuteCommand("AllInstanceNames /")instanceNames = result.item(0)


Life Before the API : Connect Revisited

• Benefits– Straightforward implementation, does not require a lot of

development skill or experience– Almost all of the functionality available from the STK

GUI can be executed using Connect

• Limitations– It is difficult to memorize the syntax of commands– Limited exception handling– Most commands with a return value need further parsing

to be more useful


Overview of the API

• What is it?– COM type library that provides an object model that

represents STK objects– Version History

• Released starting with STK version 6.1.3 as the ‘STK Data Provider API’

• Renamed to ‘STK Object Model API’ in STK version 7


Overview of the API

– Object Model Features• Application / Scenario level

interfaces• STK object-related interfaces• Data Provider-related

interfaces

– Object Model Diagram


Using the API

• Installation– System requirements same as STK– Installation procedure

• Before STK 7, separate installation package

• Setting up a development project• Add a reference to ‘AGI STK/Objects 7’

(AgStkObjects.dll – located in the bin folder)


Using the API

• Demo application– Object Initialization– The Object Root (AgStkObjectRoot)– Working with scenario objects (IAgStkObject)– Accessing Data Provider information– Multiple Threshold Crossings– Events


Using the API

• Object Initialization– Using with STK/X

Dim m_stkApp As AgStkObjectRootSet m_stkApp = New AgStkObjectRoot


Using the API

• Object Initialization (continued)– Using with STK

‘Load STK (reference AgUiApplicationLib)Dim uiApp As AgUiAppDispImplSet uiApp = New AgUiAppDispImplWith uiApp.LoadPersonality "STK".Visible = True.UserControl = True

End With‘get object rootDim m_stkApp As AgStkObjectRootSet m_stkApp = uiApp.Personality2


Using the API

• The Object Root (AgStkObjectRoot)– Implements various interfaces

• Application-level (IAgStkObjectRoot)– NewScenario, LoadScenario, CloseScenario, SaveScenario– CurrentScenario– UnitPreferences– ExecuteCommand

• Animation (IAgAnimation)– PlayForward, PlayBackward– Rewind– Faster, Slower– StepBackward, StepForward– CurrentTime

• Batch Update (IAgSupportBatchUpdate)– BeginUpdate– EndUpdate


Using the API

• Working with Scenario Objects– IAgStkObject - Interface for a generic object

• InstanceName• ClassType, ClassName• Path• ShortDescription, LongDescription• Parent• Children• DataProviders• GetAccess, GetAccessToObject


Using the API

• Working with Scenario Objects (cont’d)– Other interfaces specific to an STK object type

• Aircraft (IAgAircraft)• Area Target (IAgAreaTarget)• Facility (IAgFacility)• Ground Vehicle (IAgGroundVehicle)• Launch Vehicle (IAgLaunchVehicle)• Missile (IAgMissile)• Planet (IAgPlanet)• Satellite (IAgSatellite)• Scenario (IAgScenario)• Sensor (IAgSensor)• Ship (IAgShip)• Star (IAgStar)• Target (IAgTarget)


Using the API

• Data Providers– Enumerating Data Providers

• In STK, the data providers available to an object are listed in the ‘Content’ properties page when creating or editing a report. There is no Connect command to retrieve the list.

• In the API, the data providers can be accessed using the DataProviders property of an STK Object.

– By iterating through the collection (fine grained: provides full access to data provider objects)

– using the GetSchema method (coarse grained: returns an XML string)


Using the API

– Retrieving Data Provider Information• Commonly-used data provider types:

– Fixed– Time Varying (Start Time, Stop Time)– Interval (Start Time, Stop Time, Interval)

• Steps for retrieving data provider information1. Get a reference to a scenario object2. Retrieve the data provider from its DataProviders collection3. Call Exec

» Returns an IAgDrResult value


Using the API

– Basics of IAgDrResult• Category

– eDrCatDataSetList– eDrCatIntervalList– eDrCatMessage– eDrCatSubSectionList


• DataSets – map to the collection of columns in a report– DataSet

» ElementName» ElementType» GetValues

Using the API

Dataset

Dataset

Dataset

Dataset

Values

ElementName


Using the API

– Multiple Threshold Crossings• The API features the ability to filter a data provider result to

return time intervals where dataset values cross specific ranges– For example: return time intervals where an aircraft’s altitude

crosses 3, 4, and 5 (km); that is, return time intervals where:1. Altitude < 32. 3 < Altitude < 43. 4 < Altitude < 54. Altitude > 5


Using the API

• Events– OnAnimationPause– OnAnimationPlayback– OnAnimationRewind– OnAnimUpdate– OnLogMessage– OnScenarioClose– OnScenarioLoad– OnScenarioNew– OnScenarioSave– OnStkObjectAdded– OnStkObjectCollectionChanged– OnStkObjectDeleted– OnStkObjectRenamed


Benefits and Limitations

• Benefits– Extra features not available using Connect

• Enumerate Data Providers• Multiple Threshold Crossings• Events

– Rich object model results in strongly-typed code; easier to track errors at compile time

– Intellisense – More robust runtime exception handling


Benefits and Limitations

• Limitations– Currently supports functionality available in PRO and

AVO– Some Connect commands currently have no equivalent

• ‘VO View’• Batch update using wildcards in object paths (‘*’)

– One Connect command does not necessarily map to one API command


Recommendations

• When to use– Data Provider API

• Use the API as much as possible unless there is no equivalent to a Connect command

– Connect• Still good for ‘one-off’ applications


Summary / Conclusion

• The API provides many conveniences over Connect from a development standpoint

• Connect is not going away

Documents

Pg 1 of 30 AGI Application Programming using the STK Object Model Sylvain Dupont & Alan Ocampo Analytical Graphics, Inc October 2005