Memory Management tips when multiple layers are added to AGSMapView

AnoopMohandas

I have developed a GIS based iPad application.  When multiple layers added to map, app is receiving memory warning. The situation is more evident when tiled layers are added
When a tiled layer is added on top of previously added dynamic layers and tiled layers, how can I make sure only the visible map layer is fetching information or is using  memory.

The nearest match seemed to be using AGSLayerView to keep the underlying(invisible) dynamic and tiled layers hidden and then drawing only the visible?

Please provide suggestions.

Nicholas-Furness

Hi Anoop,

Good questions. Much of this is outside the scope of this thread and forum, but I'll try to give you some pointers.

I didn't knew about generalization and our server version is 9.31. This is something we should implement on server side rite?

Yes, server-side.

And also how can we know if a layer is not generalized?

Generalization is merely the process of reducing the "resolution" of your vector data to a level that suits your purposes (in this case, rendering at given zoom levels). For example, a polyline with thousands of points in it which is good for plotting a wall-sized map may only need one tenth the number of points to look exactly the same on a small screen.

A better question might be: How do you know whether a feature class needs generalizing? Let's just consider viewing the data (editing is another issue, and the general rule is not to edit generalized data directly). And remember this discussion is for dynamic layers only (i.e. not tiled layers).

[INDENT]
Ex. 1: You could have a problem if you zoom in on a polyline or polygon layer much further than your app needs and can still see a lot of detail. That means that when you're zoomed at a working level, the data is too detailed for what you can see at that scale.

Ex. 2: You could perhaps have a polygon that is the right level of detail, but that is much larger than your visible working area. The single polygon still needs to be pulled over in its entirety for rendering. Solving that can be a whole separate discussion.

Ex. 3: You might find (as is possibly the case here) that the data is more detailed than your client specifications allow for, and so you'd want to create a generalized set of that data just for that client app.

[/INDENT]

There is a lot to consider. Client limitations, bandwidth, managing the data, data updates, editing.

The 9.3 documentation has a short discussion on the topic and overview of the operations. You will need an ArcInfo license to use most of the tools (you'll probably need "Simplify Polygon").

For 10.0, the toolset is arranged differently but attacks the same problems.

I do work with many complex layers with boundary of various states, municipalities etc. To be exact all the layers have some kind of complex irregular graphics in it 😞

If it were me, the first thing I would do is try to show that it is these complex layers that are causing your memory issue. Either use the profiler, or create a test set of generalized layers and use those.

If so, try to categorize your feature classes: "Needs generalizing" (causes a memory warning), "could do with generalizing" (takes a while to load, but doesn't cause a memory warning), and "fine as it is". That should put you in a better position to work out your next steps (and longer term data management goals if necessary).

Hope this helps a little,

Nick.