Overwriting a service is a commonly used workflow by users to be able to update their data and see the changes automatically reflected in web maps or apps. However, properties that are also controlled by the web map JSON like symbology do not automatically update. This is not intuitive to users, as they do not understand that their web map is tied to JSON code on the back end. What the user sees is that they made a change to their service and the service is not updating.
This can be especially confusing if the user adds a layer to an MXD, overwrites their map service, and opens their new web map. The web map JSON points to /MapServer/0, /MapServer/1, etc, but does not display the newly added /MapServer/2. This leads the user to believe the publishing or the web map is broken because their layer did not update.
There is also an argument to be made for the reverse. When a user updates a service with new symbology or additional layers, existing web maps may not need to be changed. Imagine another user in the company who needed the symbology to be a specific symbol for a specific web map. When the service is overwritten, the web map creator does not want the symbology to change.
This usability issue has been brought up in numerous enhancements and bugs:
Each of these bugs and enhancements have been closed as expected behavior, and that symbology should be set at the web map level. Imagine a company that is adopting a new color scheme, or a new logo, and needs to have all symbology in web maps changed to reflect the new branding. This is a tedious task for users with a large number of web maps.
To reset the symbology, etc, the current workflow is to remove and re-add the layer to the web map. This is not a feasible solution to some users, as that means pop-up configuration, filters, etc, will be lost. We can direct users to copy the JSON for the layer prior to deleting it and pasting it into a JSON editor like AGO Assistant, but users should not have to modify back-end code to preserve pop-ups.
Steps to Demonstrate:
1. Publish any map or feature service from ArcMap or Pro to ArcGIS Online, Portal, or ArcGIS Server
2. Create a web map and add a the service to it, save the web map
3. In Pro or ArcMap, open the same source data set and change the symbology.
4. Overwrite the service using the Overwrite workflows
5. Open the web map created in step 2, the symbology changes made in step 3 are not reflected in the web map
Below is the request for functionality enhancement:
6. Open the "More Options" under the layer name in the web map (three blue dots) > choose "Reset Layer"