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## converting lat lon to x y

This is a discussion on converting lat lon to x y within the MapPoint Desktop Discussion forums, part of the Map Forums category; I have a jpeg of a mappoint map. The jpeg shows a picture of a polygon. What I want to ...

1. Senior Member Green Belt
Join Date
Sep 2003
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103

## converting lat lon to x y

I have a jpeg of a mappoint map. The jpeg shows a picture of a polygon.

What I want to know is given that I know the length and width of the jpeg (in pixels) and the coordinates of the polygon (in lat lon). How could I convet the lat lon coordinates to x y pixel coordinates.

What i'm trying to do is show an this image in a vb .net form and then overlay the image using GDI+ with an interactive polygon. The problem I obviously have is knowing where to plot my polygon.

Any ideas would be greatly appreciated.

Thanks

2. Junior Member Yellow Belt
Join Date
Dec 2005
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## X,Y conversion

Are you using MapPoint 2006, or the MapPoint Web Service? If it is the web service, there is a function to handle convert to lat/long which is pretty nice. Once you save a map off in MapPoint 2006 (or earlier) there's not really any way to reference it again from within the COM interface, it's just a gif without a bounding reference. Perhaps someone else has done a hack to workaround this, but I don't know of anyway to do it.

Mark M - MSFT

3. Senior Member Black Belt
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Hi,

You can use XYToLocation to convert x,y pixel coordinates to a Location object, and LocationToX and LocationToY to find the x,y pixel coordinates from a Location object.

If I have understeand your question then I think this should be enough to do what you wants to do.

4. Senior Member Green Belt
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Not quite what I need to do but it has given me an idea. Thanks for your help

5. ## Re: converting lat lon to x y

I know its a late reply.

It sounds like you have a image of a map and you know the co-ordinates of the 4 corners.
You also know the dimensions of the map image
It sounds like a matter of dividing the change of degrees by the pixels to determine how many degrees (or portions thereof) are passed per pixel

The map linked to below is from MP2002, and the target location is placed using a similiar technique
Map
Last edited by lfdmike; 11-07-2007 at 04:58 PM. Reason: changed from img to url tag

6. Junior Member White Belt
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## Re: converting lat lon to x y

Hi ,

I want to plot a point in a map when lattitude and longitude is given.

I have a .jpg image and i know some of the x y cordinates lattitude and longitude. No other information is available. Now i will be given with a lattiude and longitude and then i have to calculate the x y in the .jpeg image with.

Do any of you have some formulas or techinques to do this.

Regards
Anish Mathew

7. Senior Member Black Belt
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## Re: converting lat lon to x y

Hi,

depends on the zoom factor and projection of the image. but if you know 2 points on x as and also on y as then you can calculate the latitude/longitude per pixel in both directions.

8. Junior Member White Belt
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1

## Re: converting lat lon to x y

Originally Posted by Wilfried
Hi,

depends on the zoom factor and projection of the image. but if you know 2 points on x as and also on y as then you can calculate the latitude/longitude per pixel in both directions.

I know this post is really ol but I hav been searching evry where for this ....

You say if I know 2 points to the X axis and 2 to the y axis I could then calculate the lat/lon per pixel in both directions

So if I understand correctly .... then this is what I am wanting to do ...

I want know many more lat/lon of several points in both x and y positions ..

I would like to then be able to select any point lets say of a given x,y coordinate then and figure its lat/lon value ... cane be done Yes?

If so .... I am doing this in vb 2008 express ... If I could see the equation or its vb example either ... I could then write this so it will do exactly what we are talking about .....

All help is much appreciated ......

Mark

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