ICenterAndScale Interface

Provides access to the Center And Scale Map Area Interface.

Product Availability

Available with ArcGIS Engine, ArcGIS Desktop, and ArcGIS Server.

When To Use

Use ICenterAndScale to apply a new geographic extent to a map by specifying a center point and map scale.

Members

		Description
	Center	The center of the map.
	MapScale	The map scale.

CoClasses that implement ICenterAndScale

CoClasses and Classes	Description
CenterAndScale	The Center And Scale coclass allows you to change the spatial extent of a map by specifying the center and scale.

Remarks

One way to change the map extent is using the object CenterAndScale. Create a new CenterAndScale object and set the geographic extent of the map by setting a center point and a map scale. If the spatial reference of the MapServer object has changed, remember to adjust the spatial reference of the center point to match the new spatial reference.

[C#]

The following sample code shows how to zoom to a specified scale using ICenterAndScale. It assumes that you already have a valid MapDescription object and that you are not working with a server context. However, if you are developing an ArcGIS Server application using a server context, you should not use New to create local ArcObjects, but you should always create objects within the server by calling CreateObject on IServerContext.

IMapDescription mapDesc;

IEnvelope extent = mapDesc.MapArea.Extent;
double lXMin, lXMax, lYMin, lYMax;

lXMin = extent.XMin;
lXMax = extent.XMax;
lYMin = extent.YMin;
lYMax = extent.YMax;

// Calculate center point of current map extent
IPoint centerPoint = new PointClass();
centerPoint.SpatialReference = mapDesc.SpatialReference;
centerPoint.X = lXMin + (lXMax - lXMin) / 2;
centerPoint.Y = lYMin + (lYMax - lYMin) / 2;

// Assign center point and map scale to new CenterAndScale object
ICenterAndScale centerAndScale = new CenterAndScaleClass();
centerAndScale.Center = centerPoint;
centerAndScale.MapScale = 2000000;

// Assign new CenterAndScale object to MapDescription
mapDesc.MapArea = (IMapArea)centerAndScale;

[Visual Basic 6.0]

Dim pMapDesc as IMapDescription'Get coordinates of current map extent Dim pExtent As IEnvelope Dim lXMin As Double, lXMax As Double, lYMin As Double, lYMax As Double Set pExtent = pMapDesc.MapArea.Extent lXMin = pExtent.XMin lXMax = pExtent.XMax lYMin = pExtent.YMin lYMax = pExtent.YMax 'Calculate center point of current map extent Dim pCenterPoint As IPoint Set pCenterPoint = New Point Set pCenterPoint.SpatialReference = pMapDesc.SpatialReference pCenterPoint.x = lXMin + (lXMax - lXMin) / 2 pCenterPoint.y = lYMin + (lYMax - lYMin) / 2 'Assign center point and map scale to new CenterAndScale object Dim pCenterScale As ICenterAndScale Set pCenterScale = New CenterAndScale pCenterScale.Center = pCenterPoint pCenterScale.MapScale = 2000000 'Assign new CenterAndScale object to MapDescription pMapDesc.MapArea = pCenterScale

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