how to handle multiple pins are going to dropped at a one longitude & latitude in iphone sdk?

I have one task to develop application with map-kit.
I am getting multiple pins from server and one pin i have to drop from user current location. This user current location pin should be green & other pins which are coming from server should be in another color.How can i do this??

and another question is i am getting some pins on one another because there latitude & longitude have some minor differences. so at that particular point where the pins are going to be dropped on one another that point i want to give one button (on pin pop up window) which handle the minor difference of lat & long pins means the button tells next pin & as soon as the button pressed the pop up window should go on another pin which is not already selected & open its pop up window which also tells next pin. how can i do this??

i am using code like this for creating pin

for getting user loacation pin

        Place* current = [[[Place alloc] init] autorelease];
    current.name = @"You are here.";
    current.latitude = coordinate.latitude;
    current.longitude = coordinate.longitude;
    PlaceMark *from = [[[PlaceMark alloc] initWithPlace:current] autorelease];              
    [mapView addAnnotation:from];

for getting server location pin.

    int s=1;
    for (j=0 ; j < i - 1   ; j++) 
    {
        //points = [[NSString alloc] initWithFormat:@"point%d",s];
        reports = [NSArray arrayWithArray:lat];
        NSString *titles = [[NSString alloc] initWithFormat:@"%@",[tit objectAtIndex:j]];
        NSString *description = [[NSString alloc] initWithFormat:@"%@",[des objectAtIndex:j]];
        float latitude=[[lat objectAtIndex:j] floatValue];
        float longitude=[[lon objectAtIndex:j] floatValue];
        Place* home = [[[Place alloc] init] autorelease];
        home.name = [NSString stringWithFormat:@"%@",titles];
        home.description = [NSString stringWithFormat:@"%@",description];
        home.latitude = latitude;
        home.longitude = longitude;
        PlaceMark *from = [[[PlaceMark alloc] initWithPlace:home] autorelease];             [mapView addAnnotation:from];
        s++;
        [self centerMap];
    }

this code for creating there popup window.

- (MKAnnotationView *)mapView:(MKMapView *)map viewForAnnotation:(id <MKAnnotation>)annotation{
if (annotation == mapView.userLocation)
return nil;
MKPinAnnotationView *pin = (MKPinAnnotationView *) [mapView dequeueReusableAnnotationViewWithIdentifier: @"asdf"];
    if (pin == nil)
    pin = [[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier: @"asdf"] autorelease];
else
pin.annotation = annotation;
pin.userInteractionEnabled = YES;
UIButton *disclosureButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure]; 
[disclosureButton setFrame:CGRectMake(0, 0, 30, 30)];
pin.rightCalloutAccessoryView = disclosureButton;
pin.pinColor = MKPinAnnotationColorRed;
pin.animatesDrop = YES;
[pin setEnabled:YES];
[pin setCanShowCallout:YES];
return pin;}

this code for handle there events means pin is calling the button action.

 - (void)mapView:(MKMapView *)mapView annotationView:(MKAnnotationView *)view calloutAccessoryControlTapped:(UIControl *)control
{ nslog (do something)
}

My all codes are working properly. i want just answer of above given questions..pls help me

Solution

Answer For your first question:

First Find your current location refer THIS ANSWER with all comments But use Following code to do this.

#pragma mark -
#pragma mark Location Manager functions

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{   NSLog(@"Inside Location Delegate"); 
/*NSString *val=[[NSString alloc] initWithFormat:@"Previous Location is:\n Lattitude : %f\n Longitude : %f \n\n Current location is :\n Lattitude : %f\n Longitude : %f",oldLocation.coordinate.latitude, oldLocation.coordinate.longitude,newLocation.coordinate.latitude, newLocation.coordinate.longitude];
NSLog(@"%@",val);*/
[self setMapCenter:newLocation.coordinate];

PlaceMark *addAnnotation = [[[PlaceMark alloc] initWithCoordinate:newLocation.coordinate] retain];
[addAnnotation setTitle:@"Your Location"];
[addAnnotation setSubTitle:@""];        
[self._mapView addAnnotation:addAnnotation];
userAnnoFlag = TRUE;

[self._mapView selectAnnotation:[[self._mapView annotations] lastObject] animated:YES];

[self.locationManager stopUpdatingLocation];
}

Then Use following method to set the pins:

#pragma mark -
#pragma mark Annotations Functions

- (MKAnnotationView *) mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>) annotation{
@try {
    MKPinAnnotationView *annView=[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:@"MyPin"];  
    annView.animatesDrop=FALSE;
    annView.canShowCallout = YES;
    [annView setSelected:YES];
    if (userAnnoFlag == TRUE){
        annView.pinColor = MKPinAnnotationColorRed;
        userAnnoFlag = FALSE;
    }
    if ([mapView userLocation]) {
        annView.pinColor = MKPinAnnotationColorRed;
    }
    else{
        annView.pinColor = MKPinAnnotationColorGreen;
    }   
    annView.calloutOffset = CGPointMake(-5, 5); 
    return annView;
}
@catch (NSException * e) {      
}
@finally {      
}
return 0;
}

And in case of your second question, you better check the difference between latitude and longitude, manually, and pass it if it has a enough difference(according to your requirement).