Do marker namespaces and ids actually do anything?
I am having trouble understanding the purpose of namespaces and ids as applied to markers. I am specifically referring to some of the info provided on this wiki page.
It says that if a marker has the same namespace and id as an existing marker, then it will clear the existing marker. I have not found this to be the case. In fact, I had been setting all of my markers to the same namespace and id without any problem.
Additionally, I don't understand how this behavior could even be achieved. A publisher can only publish a single topic and hence can only publish a single marker. Isn't the topic name the true unique identifier for markers?
The reason I am asking is because I am writing a class that "manages" a bunch of markers.
" A publisher can only publish a single topic and hence can only publish a single marker." No. The publisher can first publish a marker with id 0 and then a marker with id 1 on the same topic. How have you published your markers with the same namespace and id?
I published them with different publishers. I have my marker topic latched, maybe that is the problem...?
The namespace/id-combination only has to be unique within a single topic. Otherwise someone else could overwrite your markers to easy. So if you send two markers on different topics, they will never interfere.