I know there are a few questions about this but i just cant seem to find any good answer to the question. What I am doing is fetching information from a db and collect the info into annotations on a map in mapview (Iphone).
What I want is to update the information from the database every second or so and update the annotations so that the new locations is shown on the map. So for instance if coordinates are moving it will show the movement every second. Are there any standard methods for this or any other good fixes?
You can use [yourAnnotation setCoordinate:newCoordinate];
Pls see if this SO question helps you MKMapView moving Annotations Automatically - animate them?
Related
I am working on the map application and as per requirement i need to show a single pin for a single region even if it has multiple user coordinates when its completely zoomed out but when its zoomed in to the map then i should display all the pins as per its coordinates.
I have given example below to explain my problem.
I have city New York on this city I have 100 pins on my mapview when I am zooming out of my map it should show me only one annotation pin on the place of 100 pins but when I am zooming in then it should show again 100 pin on map.
Does any one knows about this. I need suggestion. Please note that I am getting all the locations from web services except my current location. This should not be affecting application so that application shouldn't become slow.
Please suggest some solution.
The Apple WWDC 2011 video, "Visualizing information geographically with MapKit", https://developer.apple.com/videos/wwdc/2011/
shows how to cluster map annotations - it's exactly what you need.
Of course there is a control for that...
Take a look at OpenClusterMapView, it should be exactly what you need.
There is no API for this.
You will need to manage the pins yourself. As a user zooms in on the map, you will need to decide at what point to remove the aggregated pin and add the individual pins. Inversely, as a user zooms out you will need to remove the individual pins and replace with the aggregated pin.
Might be a good idea to use a custom pin for the aggregated pin to suggest that it represents multiple pins.
I think this link might help you know the current zoom level:
Zoom and Region
Link to a similar question:
Pin Overlap
I'm in a situation where there will be 500+ annotations to load onto a map. What some ways that you have dealt with the resulting lag with so many annotations on the map?
One thing I've considered: only loading a portion of the annotations based on the current map region in view. But what happens when they zoom out or move around? Reload based on the region displayed?
MKMapView has a dequeueReusableAnnotationViewWithIdentifier: method (documentation) that I believe you're supposed to use. It looks like it works similarly to UITableView's dequeueReusableCellWithIdentifier: method.
Another thing might be to group clustered pins together into one pin. As you zoom in, you can expand these groups.
update: Found a cool open-source library that might be useful for dealing with tons of annotation points: ADClusterMapView
I've problem with Objective C at the moment with developing something special.
So - after the MKMapView is initialized and the users position is shown, I would like to implement a method to show annotations which are next to users position. I've stored all necessary points in an SQLite database in a special table. I've two fields - namely lonand lat- I think it's clear what is meant by that.
Has anybody an idea how to show JUST those annotations which are visible at the screen to be as performant as possible. After the user scrolls the map - it should call the method again to look up in database wether there are also other points which need to be shown...
Thank you very much in advance for your help,
kind regards,
Dominik
You will need to do a few things.
1) Get the center of your map - use the centerCoordinate property of your MKMapView
2) Ask your database for all items within a certain distance from the center of the map.
3) Display them
It's (2) that's the tricky one - you need a method that will return all items near to the lat lng you have.
This link has a handy implementation of how to do that :)
Hope that helps.
A couple of points:
If you're using iOS4, the mapview behaviour has changed so that it automatically saves memory by only creating the annotations which are in the visible view.
Secondly, in the same way that you can create a tableview with thousands of cells and still have it scroll smoothly, the annotations offscreen don't affect the performance that much. You should be keeping your annotations very small so they don't consume much memory. The annotation views are the ones that take up the memory.
Your problem is going to come when the user zooms out and there are too many annotation views visible at the same time. When you're zoomed in, you don't need to worry too much about off-screen annotations.
Really hope someone can help me as I'm a bit stuck :S
I have a custom map of an event using the CATiledLayer so users can zoom in and scroll around the map. What I would like to do now is add the functionality to let the user know where they currently are on the map. I know it can be done as I've seen an app do this before. I'm not sure how to go about doing it though, maybe I need to convert lat/lon into pixels but I'm not sure if thats possible (depending on how big the image is, etc).
On another site it was mentioned to find out the boundaries of the map and then I can add pins to the map, but I'm not sure how to go about doing this? Will I need to find every coordinate (lat/lon) within the boundary so I can add the pin of where the user is currently?
If anyone can give me with any advice or pointers, I'd much appreciate it
You can use the route-me library by adding your own map source class. A good article that explains how to do it is here http://mobilegeo.wordpress.com/2010/07/07/route-me-native-iphone-mapping-framework/
I'm facing a challenge right now in trying to map GPS coords to a map that's an artist's rendition. In particular this is for a ski mountain, so the artist's rendition is a "trail map". The trail map is not accurate in that the whole mountain has been squeezed onto the one view, yet the actual topology of the mountain doesn't conform to the drawing.
I've tried several approaches:
1) Triangulation using known GPS coordinates of the lift stations. This is fairly simple to implement, yet this is not accurate enough and the algorithm fails if the rendition differs enough from the GPS map.
2) Creating a uniform grid for both the GPS map and the Trailmap, then doing a mapping from cells in the GPS map to the Trailmap. The downside to this is it can be a lot of busy work with no easy UI for doing it.
3) Calculating the vectors of each lift (being a straight line), find the closet lift station to a given GPS point, and calculate the estimated Trailmap location using this vector.
I'm considering #2, which is essentially the simplest solution. But if you've found a better way, I'd love to hear it.
I want to make an app that partially mimics some of the behavior the standard map application has. This has proven difficult. First of all, I don't understand how you make annotations movable. How exactly do you do this?
Second: how do you search for locations?
Moving annotations
I'm assuming you're after the behavior of Maps.app where you tap and hold on to a pin to move it around freely. As far as I know, there is no built in way of moving annotations around. Since annotations are subclasses of UIView though, you can draw them where and how you'd like. You could for example detect a tap-n-hold on the annotation, and when "unlocked" change the centerOffset value of your annotation to move it around with the touch. When the user lets go of the the view, you can note the position on the screen, and use the MKMapView method convertPoint:toCoordinateFromView: to get the coordinates that the pin was released.
Search for location
What you are looking for is called Forward Geocoding. Unfortunately, MapKit only comes with Reverse Geocoding (the process of converting GPS coordinates to country/city/street/etc). There is, however, several alternatives. Here's a few ways:
http://code.google.com/apis/maps/documentation/geocoding/index.html
http://cloudmade.com/products/iphone-sdk
http://www.geonames.org/export/web-services.html
http://developer.yahoo.com/maps/rest/V1/geocode.html
Note that many geocoding APIs are licensed under Creative Commons, or similar licenses.
You should be able to get drag-and-drop annotations going with the help of this blog post. I used it to do the same thing, and it was pretty simple to get going.
MapKit annotation drag and drop with callout info update