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Identifying an existing Basemap, to avoid needless replacing.

NathanSummers1

Situation:

I am writing an app that can load different sets of user-preferences, and that can programatically change the basemap.

I have a function who's job it is to detect the changes needed for the map, and this is called whenever a user changes their layers, basemap, or when user-preferences are loaded. (the point i'm making is that there's no 'user has changed the basemap' event from the basemap widget when my alternate user-preferences are loaded).

I'm trying to detect that the basemap is not the same as the one in the preferences, and only change the basemap attribute when a difference is detected.

I'm storing a basemap.toJSON() in my user-preferences.

What can I use in that, to correlate to a basemap (that was created from basemap.fromJSON() ) ??

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Accepted answers

RobertScheitlin__GISP

I am not sure about the predictability of the order. I am not aware of any alternative,

All comments

NathanSummers1

It appears the Basemap ID is generated uniquely each time I do a Basemap.fromJSON().

I wouldn't use the Title, that seems fragile.

The Basemap object itself cant be compared to what I store ... I store the Basemap.fromJSON().

I don't think I've tried comparing currentBasemap.toJSON() with my user-preferences storage...

The toJSON method returns a JSON-compatible object (good, it's not a string!), but that makes comparison tricky, because that's a 'deep attribute by attribute object comparison'. Is there no alternative? Would it be reliable - are the layer arrays stored in a predictable order?

RobertScheitlin__GISP

Nathan,

So the maps basemap property give you a string of the basemap name or a basemap object... Can you not use that to compare?

NathanSummers1

The watch will tell me when the actual map's Basemap is changed.

I'm trying to work out if what I store in my user-preferences data is the Basemap that's already in use on the map.

So you see, I'm trying to avoid changing the map's basemap. But I can't see what I can easily compare in my user-preferences to the on-screen Basemap.

Using the latest 4.10 api.

RobertScheitlin__GISP

Nathan,

Can you not just add a watch to the maps basemap property (assuming 4.x API since you did not specify)?

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