WMS or Raster - Request image with size > 2047 pixel results map with poor image quality

[liuar]

1. connect to a WMS server (​http://osm.wheregroup.com/cgi-bin/osm_basic.xml?)

2. create a map and add the WMS layer

3. in MapAgent web tier test, send a GetMapImage request in order to render the map, set map image size < 2047x2047

4. in MapAgent web tier test, send a GetMapImage request in order to render the map, set map image size where either height or width > 2047pixel

5. compare both maps

Result: image quality drops significantly if map image size width or height is higher than 2047 pixel

Expected: image quality should be same

[liuar]

Following code in rendering service results this issue

RasterAdapter::Stylize()
{
  ...
  while (imgW >= 2048 || imgH >= 2048)
  {
      imgW >>= 1;
      imgH >>= 1;
  }
  ...
}

After the discussion with Walt, Zac and Bruce, it would be a better idea to make the max width and height be configurable via serverconfig.ini.

[brucedechant]

Added Walt's comments:

Hi Arthur,

I looked at the patch, and it looks fine. The names for the new settings also sound reasonable to me. I only have minor / nitpicking comments:

• In ServerRenderingService.cpp, move the newly added calls to pConf->GetIntValue to before the "there should be only one instance of this class" comment. Otherwise it looks like the comment applies to your new calls as well and it doesn't make sense.

• Throughout your patch you declare height before width, e.g.:

# MaxRasterImageHeight The max height of raster image in pixels # 0 < Value <= 2147483647 # MaxRasterImageWidth The max width of raster image in pixels # 0 < Value <= 2147483647

I think most people like to see it the other way around - width then height - just like for point coordinates we prefer X then Y. So switch the order throughout your patch to width then height.

Thanks, Walt

[liuar]

Hello Walt,

I updated the patch according to your comments. Thanks for your review.

Regards,
Arthur

[liuar]

Changeset [5135] by liuar