Coordinates from Event Layer

Permanently deleted user

18 Juni 2012 20:22

I have workflow that works against an event layer that needs to the zoom the extent of the selected feature. The issue I am having is that event layers do not return geometry as part of the query so I can't extract the extent as I would for a typical query against a featureset. The event layer does have Latitude and Longitude as attribute values. How can I use the Latitude and Longitude values from the resultant feature set to generate an extent that I can zoom to in Web Mercator?

Thanks,

Aaron

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  Ryan Cooney

  18 Juni 2012 23:19

  Hi Aaron,

  If you create a MapPoint out of your X and Y and assign it a new SpatialReference using WKID 4326, you should be able to call ESIR.ArcGIS.Client.Projection.WebMercator.FromGeogaphic(...) to convert it to Web Mercator.

  (http://help.arcgis.com/en/webapi/silverlight/apiref/ESRI.ArcGIS.Client~ESRI.ArcGIS.Client.Projection.WebMercator~FromGeographic.html) http://help.arcgis.com/en/webapi/silverlight/apiref/ESRI.ArcGIS.Client~ESRI.ArcGIS.Client.Projection.WebMercator~FromGeographic.html

  --Ryan

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  Permanently deleted user

  19 Juni 2012 00:57

  Ryan,

  I have the MapPoint created and have assigned .X, .Y and .SpatialReference (4326); however, I'm not following you on how to project to Web Mercator (102113) through Workflow.

  Thanks,

  Aaron

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  Permanently deleted user

  19 Juni 2012 01:31

  Ryan,

  I followed the approach described in this post, https://support.geocortex.com/Forums/Thread.aspx?pageid=0&mid=2&ItemID=20&thread=45726&postid=132159, to re-project and the coordinates look good. The problem I am having now is zooming to the extent of the projected point using the following Value for the "SetMapExtent" activity: BridgeGeometry.Extent().expand(3); where BridgeGeometry is of type Geometry. The map doesn't seem to change extents.

  Thanks,

  Aaron

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  Ryan Cooney

  19 Juni 2012 03:25

  Hi Aaron,

  The issue here is that the extent of a MapPoint has zero width and height. The map will not zoom to an extent with no size. The Expand(3) method just triples the width and height, so you are still left with zero size. You've got a couple options:

  1. You can pass your MapPoint into a BufferTask activity and buffer it by an actual distance (say 100 Meters) to get a Polygon. This will have an extent with a valid size that you can use.
  2. You could also just create a new extent from your MapPont by using an Assign activity with an expression like: 

  new Envelope(point.X - 100, point.Y - 100, point.X + 100, point.Y + 100)

  --Ryan

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  Permanently deleted user

  19 Juni 2012 04:24

  Ryan,

  I went with option two and everything is working as expected now. Thanks, for clarifying the issue and providing two solutions.

  Aaron 

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