write coordinates into SQL Server

[David Lowther]

William,

 

Correct me if I am wrong, but what you are after here is how to translate an
image click into map coordinates, right?  I suspect that the actual creation
of rows in SQL Server with the x, y coordinate values is straightforward.

 

In order to get the map coordinate from the image click you have to do a bit
of legwork since there is no direct method call for this in mapscript (that
I am aware of). You are using mapscript_csharp, right? Here's a bit of code
that may help you given that you have a mapextent, image width and height,
and image x, y click location:

 

Public Shared Function ConvertImageToGeo(ByVal imgExtent As GISExtent, ByVal
targExtent As GISExtent, ByVal imgPoint As GISPoint) As GISPoint

            '//images have 0,0 in upper left corner - effectively switching
the orientation of the axis

            Dim targPoint As New GISPoint

 

            '//make sure imgpoint is inside imgextent

            If Not imgPoint.x <= imgExtent.xMax Or Not imgPoint.x >=
imgExtent.xMin Or _

                Not imgPoint.y <= imgExtent.yMax Or Not imgPoint.y >=
imgExtent.yMin Then

                Return Nothing

            End If

 

            '//precentage along the x and y axis

            Dim xPercent, yPercent As Double

            xPercent = (imgPoint.x - imgExtent.xMin) / imgExtent.Width

            yPercent = (imgPoint.y - imgExtent.yMin) / imgExtent.Height

 

            '//since y axisorientation is backwards - take inverse
proportion of yfactor

            yPercent = 1 - yPercent

 

            '//calculate offset

            Dim targXOffset, targYOffset As Double

            targXOffset = targExtent.Width * xPercent

            targYOffset = targExtent.Height * yPercent

 

            '//calculate point

            targPoint.x = targExtent.xMin + targXOffset

            targPoint.y = targExtent.yMin + targYOffset

 

            Return targPoint

 

        End Function

 

 

If you are on the client side (javascript) you can use this if you populate
ImgW, ImgH, MapULX and MapULY beforehand. 

 

function SetMapLoc(imgX, imgY){

    var pX = imgX / ImgW;

    var pY = imgY / ImgH;

 

    var mapXAdd = MapW * pX;

    var mapYAdd = MapH * pY;

 

    MapX = MapULX + mapXAdd;

    MapY = MapULY - mapYAdd;

    

    MapX = MapX.toPrecision(8);

    MapY = MapY.toPrecision(8);

}

 

Note that neither of these methods is very precise so if you are looking for
precision, you'll need something more sophisticated.

 

Hope that helps,

 

David Lowther

 

Coordinate Solutions, Inc.

501 N.E. 15th Street

Oklahoma City, OK 73104

405.246.9396 (Voice)

405.227.0781 (Fax)

www.coordinatesolutions.com

 

  _____  

From: william paul [mailto:williampaul28 at YAHOO.COM] 
Sent: Wednesday, November 08, 2006 2:26 PM
Subject: write coordinates into SQL Server

 

Hi:

 

I would like to create point data by clicking on the map and write the
coordinates into SQl Server 2005. It's the opposite of OVF file for creating
points from 2 columns from a DBMS (like Sql Server, MySql)

 

When I click on the map I would like to take automatically the coordinates
and record them together with other attributes into a table (Sql Server|)
with 2 columns for x and y coordinates

 

Is it possible to do it?

 

I am using mapserver 4.10, dBox on IIS server and ASPX with Sql Server 2005

 

 

Thank you in advance

 

William

  

  _____  

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