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Response of the DemoMapHandler in Demo is indeterminate

Topics: SharpMap v2.0
Jul 27, 2010 at 3:10 AM

Hi all,

I've used the Demo of SharpMap v2.

But, I get the problem about the response of DemoMapHandler.

With the same parametres of query, but the response of DemoMapHandler is different with each time of query.

Example, at first, when I load the DemoSharpLayer, there are some images wrong. Then I've resent request of image and the response is correct.


I think that error is caused by AsyncMapHandlerBase and MapHandlerBase. Because, when the server generate image, it is interrupted. I think so.

But, I tried to implement MapHandlerBase instead of AsyncMapHandlerBase. But the error exists.

So, I think that is error of GdiRenderer.

Any suggestion?


Jul 27, 2010 at 12:13 PM
Hi thuanvh, please can you explain the behaviour you are seeing or link to images. There are definitely issues with the GDI renderer when used as a service e.g in a website (Microsoft do not support GDI+ running as a service at all), these manifest themselves usually as either a broken image or a monochrome one. There are also issues with the ShapefileProvider when used in a website due to locks being placed on the underlying file. hth jd
Jul 27, 2010 at 2:19 PM
Edited Jul 27, 2010 at 2:20 PM
Simplement, I get 2 differents images with the same url.

Par exemple:

Imagine that I query an image of the north of Atlantic. The correct image have to contain one part of north America, one part of west Europe, one part of north Africa.
But, sometimes, I get the wrong image containing only one part of the north America with the same query.
So, I think that is caused by an image renderer.

I'm in use of code from trunk in Sharpmap v2. And this exemple is in the demo of SharpMap.Demo.AspNet and SharpMap.Demo.SharpLayers.
Jul 28, 2010 at 9:09 AM
Hi thuanvh,

it is quite possible, the web side needs some love.

Do the tiles in question wrap the date line? Are there any unusual coordinate systems in use?

cheers jd