07-20-2020 06:37 AM
Our customer is using ECW plugin for ArcGIS server for the first time.
I've managed to do the installation and testing with them few months ago.
I just received an email showing how the published ecw is not the same quality as the image itself.
Since i don't have the plugin installed locally and I'm not expert in using it, i was wondering if there might be some configuration the client is missing.
For example, when hey publish using ArcMap, there is a compression parameter. What does that do? She tried to change it (going from 85 to 15) but that doesn't change anything.
A little help here would be very much appreciated
Please find attached the ecw data after publishing also the original data (accessed in ArcMap)
07-20-2020 09:33 PM - edited 07-20-2020 10:21 PM
What version of the plugin and arcgis server is this? What does it look like if they are publishing as PNG? It does look like the JPEG compression is too high, but if they say that makes no difference, then unsure what the issue is. Open a support issue with sample data and we will take a look.
Additionally, changing the JPEG compression in the ArcGIS image service would require them to clear the arcgis cache, as well as the browser cache before they would see any changes on the client. I would suggest changing the output format to PNG first and comparing to make sure its not the output compression thats the issue.
07-22-2020 05:26 AM - last edited 2 weeks ago by fcaelen
The client is using the version 10.6.1 for both the plugin and ArcGIS Server.
I've asked for the PNG test but didn't get the feedback yet.
I will do a remote session with them this afternoon and try to change the JPEG compression (and make sure the cache is cleared).
I will also test the PNG.
They have asked for ESRI support in parallel and the support guy says something the customer wants me to clarify/ He says:
Use JPEG format for basemap with a great variation in colors and that doesn't need a transparent background. The JPEG format is generally fit fot raster imagery and very detailed vector basemap.
JPEG is an image format with loss. He tries to delete data in a selective manner without affecting the image appearance. This creates very small tiles on the disk but if your map contains a linear vector network or labels, it can produce too much noice or fuzzy regions around the lines. If this is the case, you can increase the compression value which is 75 by default. A greater value, like 90, helps balance an acceptable quality of the drawing thanks to the reduced tile size for JPEG format.
Not sure what to take from this appart that they are implied a higher compression value equals a better quality for their kind of data. Which is in contradiction with what i've asked the client to do to get better quality.
I will see soon enough what really going on but any thought on the paragraph above is very welcomed.
Thanks very much
07-22-2020 05:56 AM
Just got a feedback from the customer.
They found out that the issue was a limitation on their ArcMap resolution and not the published data or even the plugin.
So yeah, false alert.
Thanks again for the help.
07-30-2020 01:11 AM
The cutsomer is now saying they have done the investigation with ESRI and that this is not the issue.
They tried with a published jp2000 and it was all okay quaity wise in all their user interfaces and thus it must be an issue with the ECW plugin.
They also said that now they are doing direct reading and not caching anymore and same quality issue.
I have a planned remote session with them tomorrow morning (10 am Paris time) and I would like to know beforehand if there is any type of default paramater in the plugin that might impact the quality?
Are there any specific test that you can recommend (in addition of testing png and changing the compression rate)?
08-05-2020 08:22 PM
No there are no quaility settings in the server plugin. Seeing the output using PNG would determin if this is an ECW issue or something with the ArcGIS configuration. If there is an issue, we may need some sample data to reproduce.
08-06-2020 03:30 AM
However regarding this specific issue, I've been able to do the remote session with the customer and everything was fine during the session
They said that the only difference was the internet connexion during publishing (and i've seen the previous published ecw and it was poor quality).
So they concluded that they need to publish only with high internet debit.
Does that make sense for you? What do you think?
08-07-2020 01:18 AM
No doesnt really make sense, while it may be slower with poor internet, the image quality of the resultant jpg tile should be identical. There is something going on here, but from the available info I cant work out what. Sorry!