sorting data into NSMutableDictionary?

Hello,
I have some objects with coordinates and those should be used to create annotations to be set on a map. The problem is that some of the objects have the same coordinate values, ie they are located on the same address.
I only want one pin for each address on the map, but I want the information for all objects associated with this coordinate, to be shown when the user clicks on the pin.

The starting point is that I have an array with all the objects and somehow I have to seperate and group them properly. The I have to create one annotation for every coordinate.

I think it might be good to use a NSMutableDictionary in this case but I am not sure how to structure this? Any ideas?

Thanks in advance!
MACloop

 

Well, the simple soultion is often the best one ;-) How would you fill those arrays? I mean, without being for-looping for a very long time?

Perhaps you could give me an example how to go through two arrays. One with coordinates and one with objects each having a coordinate. If we have, say 5 coordinates and 50 objects. How must I devide those 5 coords into 5 arrays and then devide the array with objects into the "proper" coordinate array...

Thanks a lot for your help!
MACloop

 

Thanks for the answer!
I have implemeted somthing like that already and so far so good.
I create a dict and add all the coords as keys and an empty array as object for each key. Then I iterate the array with all the objects and also (this is perhaps not the fastest solution..?) iterate the dictionary in order to compare the key with the object's coordinate. I use the coords as string in both cases, ie the key is a sting and I compare the object coordinate like you suggested.

So now all the information is sorted ok, I think. The next step will be to make a custom annotationview. I want to show all object-names associated with one coordinate, when the pin on the map is clicked. As far as I see, the framework does not support very much altering for an annotation callout... do you have any good advice here? I found this and think it is interesting. I would like to add a button for each object associated with a specific coordinate. When the user clicks this button, I intend to show a detailed view for this object...

Again - thanks alot for the help!
MACloop