ArcGIS Developer Help

IMapServer2.FromMapPoints Method

Converts a map coordinate to a screen location.

[Visual Basic .NET]
Public Sub FromMapPoints ( _
    ByVal MapDescription As IMapDescription, _
    ByVal mapDisplay As IImageDisplay, _
    ByVal mapPoints As IPointCollection, _
    ByRef screenXValues As ILongArray, _
    ByRef screenYValues As ILongArray _
)

[C#]
public void FromMapPoints (
    IMapDescription MapDescription,
    IImageDisplay mapDisplay,
    IPointCollection mapPoints,
    ref ILongArray screenXValues,
    ref ILongArray screenYValues
);

[C++]
HRESULT FromMapPoints(
  IMapDescription* MapDescription,
  IImageDisplay* mapDisplay,
  IPointCollection* mapPoints,
  ILongArray** screenXValues,
  ILongArray** screenYValues
);

[C++]
Parameters
MapDescription [in]

  MapDescription is a parameter of type IMapDescription*
mapDisplay [in]

  mapDisplay is a parameter of type IImageDisplay*
mapPoints [in]

  mapPoints is a parameter of type IPointCollection*
screenXValues [in, out]

  screenXValues is a parameter of type ILongArray**
screenYValues [in, out]

  screenYValues is a parameter of type ILongArray**

Product Availability

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

[C#]

The following sample code shows how to convert the upper left corner of your map extent (map coordinates) to a screen location. It assumes that you already have a valid MapServer and MapDescription object, and that you are not working with a server context. However, if you are developing an ArcGIS for 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.

IMapServer mapServer;
IMapDescription mapDesc;

// create image display
IImageDisplay imageDisp = new ImageDisplayClass();
imageDisp.Height = 400;
imageDisp.Width = 600;

// Get map coordinates (upper left corner of map extent)
IEnvelope extent = m_MapDesc.MapArea.Extent;
IPoint point = new PointClass();
point.X = extent.XMin;
point.Y = extent.YMax;

// add point to point collection
IPointCollection pointCollection = new MultipointClass();
System.Object pMissing = System.Reflection.Missing.Value;
pointCollection.AddPoint(point, ref pMissing, ref pMissing );

// Convert map coordinates to screen location
ILongArray screenXValues = new LongArrayClass ();
ILongArray screenYValues = new LongArrayClass ();
mapServer.FromMapPoints(mapDesc, imageDisp, pointCollection, ref screenXValues, ref screenYValues);

// Please note:
// 1. Origin of screen coordinate system is upper left corner
// 2. If aspect ratio of requested image is different from aspect
// ratio of input map, map extent will be adjusted to fit
// requested image -> following screen coordinates are not necessarily 0:
MessageBox.Show(screenXValues.get_Element(0).ToString());
MessageBox.Show(screenYValues.get_Element(0).ToString());

IMapServer2.FromMapPoints Method

Product Availability

See Also