WMS Raster layer pixelated and bad quality on ArcGIS Online maps only

[konstakuorikoski]

Hello,

I have some public Web Apps that use WMS layers coming from our ArcGIS Enterprise server. Same server provives WMS to other application and is also used in ArcGIS Pro. The problem I have is that raster image (GeoTIFF, 16bit unregistered, LZW original) that is served through server is showing as pixelated and bad quality on Online maps. And only those maps as it renders fine in all other applications. The issue is same if I publish raster directly to Online.

What I would like to know is if there's some other raster format that would be better to give proper quality. As the current rasters have transparency, we can leave even that out and control transparency with Online settings instead if that results readable images.

Attached are examples. One is how it look on Online map, the other is how servers JavaScript preview renders it.

[David_Brooks]

@konstakuorikoski I would switch to png if I was you for discrete data like this

[konstakuorikoski]

Hi,

tried with that, wasn't better. But I sarted thinking it might be issue with size. Its 170k columns to 110k rows. In same WMS, there are two smaller rasters which render ok. Not perfect, but better. If PNG helps with those, then splitting this bigger area to smaller patches and using PNG for Online might be solution. 

[konstakuorikoski]

After doing some testing with this, I've got the best combination. For some reason not explained anywhere that I could find ArcGIS Online does render any images when they are presented with basemaps. This means that bigger and more detailed images are generalized. With our rasters which are designed with 1:1000 accuracy it means thicker lines or thinner lines (less dots) depending on the original image.

For our rasters which are originally 1bit TIFFs in local coordinate system and then converted to 16bit TIFF for distribution this results as blurry and unreadable mess in Online. Other systems, including Pro, will render WMS correctly.

The workaround is to export rasters to WGS84 World coordinate system. This provides clearest quality. Format between PNG and TIFF doesn't matter. Nor does really any setting used when shared from Pro to Online. Only Pixel depth (16bit for thin and 1bit for thick) and coordinate system will have effect.