1

I uploaded a 300 dpi png (2024x1012) as world image to my geoserver. The image/map is displayed as WMS layer on a virtual globe in an android app. Unfortunalty, the layer on my globe gets pixelated heavily when I zoom in the image/map. How can I fix this and get a highresolution WMS layer to my app?

I use the following framework:

http://www.glob3mobile.com/

The glob3mobile engine generates 8 requests to receive tiles of the image. One of the 8 requests looks like this:

http://192.168.175.80:8080/geoserver/cite/wms?REQUEST=GetMap&SERVICE=WMS&VERSION=1.1.1&WIDTH=512&HEIGHT=512&BBOX=-180.0,-90.0,-90.0,0.0&LAYERS=cite:imagename&FORMAT=image/png&SRS=EPSG:4326&STYLES=&TRANSPARENT=FALSE

| improve this question | |
  • 1
    please add an example request to your question so we can see what you are looking for. You may also want to add which app you are using. Most likely reason is that you have asked for too small an image – Ian Turton♦ Jun 24 '15 at 15:53
1

You have asked for an image of the whole world (-180->180,-90->90) to be drawn in a 256x256 image. I'm not surprised that it looks a bit pixelated.

There are two problems here:

  1. 256x256 is very small so I suspect that the App is upSampling the image to fill the screen. This will make your image look blocky.
  2. WMS servers are not allowed to assume that you don't know what you are doing or that you must have square pixels so it takes you at your word and generates rectangular pixels that are twice as high as they are wide to allow for the fact you have asked for a rectangular geographic area in a square image. I highly doubt that your client is smart enough to handle this well.
| improve this answer | |
  • I think, the size is not the problem. The whole image that I uploaded to the geoserver has the size (2024x1012, 72dpi). The glob3mobile engine generates 8 requests to receive tiles of the image. The request from above is one of the 8 requests. So only one tile is a 256x256 image. Today, I detect that only when I zoom in, the map gets pixelated. Do anybody know how I can solve this? – treunel Jun 25 '15 at 12:01
  • if your client is generating the request above then it is requesting the whole map in one image. If it asking for tiles then something is off about it's requests. – Ian Turton♦ Jun 25 '15 at 13:10
  • but the request says “BBOX=-180.0,-90.0,-90.0,0.0” which is -180->-90 and -90 -> 0 which is only 1/8th of the map. so the request ist right – treunel Jun 25 '15 at 14:24
  • I miss read the BBOX (it breaks at 90 for me) - that is still a small image. – Ian Turton♦ Jun 25 '15 at 14:28

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.