[mapserver-users] Coverting lat/long to pixel

[Sucharita Samuel]

 Thanks Brian.
 I actually need to find the intersection of a rectangle and circle. As you
must be aware that a  circle in mapserver terminology is a shapeobject drawn
using the upper left and bottom right co-ordinates of a rectangle.
     In the above case I get the intersection of two rectangles, but as the
circle lies inside the rectangle, i am not able to find whether my first
rectangle intersects with the bottom corner of the rectangle(that contains
the circle), which is not part of the circle.
    Any solution in this case would be of great help.

Thanks,
Sucharita


On Wed, May 7, 2008 at 6:33 PM, Hulbert, Brian <brian.hulbert at linquest.com>
wrote:

>  Something else to consider if your map uses multiple (or switches
> between) "projections".
>
>
>
> My C# map application uses both equirectangular and orthographic
> projections.  Therefore, I do the following before the lines of code that
> Sandeep presented:
>
>
>
>             // create a Mapserver pointObj for the point being converted
>
>             pointObj pObj = new pointObj(location.LongitudeDeg,
> location.LatitudeDeg, 0, 0);
>
>
>
>             // create 2 projection objects - a From projection object (a
> latlong projection) and a To projection object (the current projection)
>
>             projectionObj projectionFrom = new projectionObj("+proj=latlong
> +ellps=WGS84 +datum=WGS84 +over");
>
>             projectionObj projectionTo = new projectionObj
> (m_baseMap.getProjection());
>
>
>
>             // perform the projection of the point from the current
> projection to a latlong projection; the point's x (lon) and y (lat) are
> updated in place
>
>             bool bSuccess = (((int)MS_RETURN_VALUE.MS_SUCCESS) ==
> pObj.project(projectionFrom, projectionTo));
>
>
>
>             if (bSuccess)
>
>             {
>
>                   // Sandeep's code here
>
>             }
>
>             // cleanup temporary objects
>
>             pObj.Dispose();
>
>             projectionFrom.Dispose();
>
>             projectionTo.Dispose();
>
>
>
> Brian
>
>
>
> *From:* mapserver-users-bounces at lists.osgeo.org [mailto:
> mapserver-users-bounces at lists.osgeo.org] *On Behalf Of *Sucharita Samuel
> *Sent:* Wednesday, May 07, 2008 7:42 AM
> *To:* Sandeep Kumar Jakkaraju
> *Cc:* mapserver-users
> *Subject:* Re: [mapserver-users] Coverting lat/long to pixel
>
>
>
>   Thanks a lot Sandeep. I think the code works.
>
> Regards,
> Sucharita
>
> On Wed, May 7, 2008 at 3:40 PM, Sandeep Kumar Jakkaraju <
> sandeepkumar.jakkaraju at gmail.com> wrote:
>
>
>
> Hi Sucharita
>
>
>
>
>
> these are example values........
>
>
>
>  private double minlat=28.6023 ;
>     private double minlon=77.2018 ;
>     private double maxlat=28.6382 ;
>     private double maxlon=77.2493 ;
>
>     private int screenwidth=2156;
>     private int screenheight=1674;
>     private Point p;
>
>
>     public Point convertLatLonToPixel(double lat,double lon)
>     {
>         double cellsizex = (maxlon-minlon)/screenwidth;
>         double cellsizey = (maxlat-minlat)/screenheight;
>
>         int ix = (int) ((lon-minlon)/cellsizex);
>         int iy1 = (int) ((maxlat-lat)/cellsizex);
>         int iy2 = (int) ((maxlat-lat)/cellsizey);
>         int iy = (int) (iy1+iy2)/2;
>
>         p = new Point(ix,iy);
>
> return p;
> }
>
>
>
>
>
>
>
>
> On 5/7/08, *Sucharita Samuel* <iworktech.sucharita at gmail.com> wrote:
>
>  Hi Sandeep,
>                    A code fragment will be really helpful.
>
> Thanks,
> Sucharita
>
>
>
>  On Wed, May 7, 2008 at 3:20 PM, Sandeep Kumar Jakkaraju <
> sandeepkumar.jakkaraju at gmail.com> wrote:
>
>
>
> This can be done using simple interpolation also
> ....................................
>
>
>
> On 5/7/08, *Sucharita Samuel* <iworktech.sucharita at gmail.com> wrote:
>
>  Hi friends,
>               Can somebody please help me with a code to convert the
> latitude and longitude of a point to pixel co-ordinates? I am using
> ASP.NET <http://asp.net/>. I have heard that GDAL has a method for this
> conversion. MS4W comes with GDAL as its tools, but I don't know how to
> implement it in C#.NET.
>
>
> Thanks in advance,
>
> Regards,
> Sucharita
>
>
>
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>
>
>
>
> --
> Thanks
> Regards
>
> Sandeep Kumar Jakkaraju
> _______________________________________________
> mapserver-users mailing list
> mapserver-users at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/mapserver-users
>
>
>
>
>
>
> --
> Thanks
> Regards
>
> Sandeep Kumar Jakkaraju
>
>
>
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