I have a lot of annotations to manage inside the mapkit view.
The rules are :
1 -only show annotations when the mapView.region.span.longitudeDelta is above 0.042
2 -only show annotations inside the visible area.
3- remove the annotations when they comes out the visible area...
How I can do that ... Share your experience...
Thanks
You need a few things. One is to search your database for the pins with latitudes and longitudes inside the map's view. This is called a bounding box. The next is to remove the annotations when they move outside the visible rect of the map. Each time the map is moved, you'll have to recalculate what pins are in the box and what pins are outside but still on the map.
One hint I can give you is to divide the visible rect of the map into squares (maybe 17 x 23 squares of 20 x 20) and figure out if a pin goes into that square. If it does, mark that square as filled, and if another pin wants to go into that square, don't let it. This will allow you to filter the pins so there aren't too many on screen at one time.
It's not an easy problem, but if you do some search around you'll find your way through it. This cluster marker code for Google Maps might help.
Related
I am developing an interactive map in HTML+JavaScript using mapboxgl (0.33.1). When the user clicks a button (which is associated with a particular location in the map), I call easeTo(), which put that location in the center of the map.
window.map.easeTo({
center: item.loc
});
Because my application has some overlapping UI over the bottom half of the map, I actually want to put that location not in the center of the map, but in the center of the top half of the map (25% from the top).
I'd appreciate if somebody could give me a hint how achieve it. My app knows the exact sizes of the window in Pixel (and also the zoom level), but (I assume) I need to convert it into the map-coordinate (from pixel) to add an appropriate offset to the "center" parameter I pass to easyTo() function.
I think I found the answer. I just need to call the project() method -- which was very hard to discover!
Is there any way to adjust the bounds of the map so that the right-edge of Russia doesn't appear over to the left? You can see in the image I have a MultiPolygon area overlaying Russia but the map and the overlay are split. I'd like that tiny piece of the country to be on the right if possible!
Edge of Russia on the wrong side of the map:
A workaround I can think of is using the maxBounds property, where you would shift the default bounds slightly to the right, along with minZoom: 1. This won't prevent the user from seeing the world several times for a short time if zoomed out far / panning outside, as it says there:
... bouncing the user back when he tries to pan outside the view
var map = L.map('map',{
maxBounds:[ [-90, -160], [90, 200] ],
minZoom: 1
}).setView([66.058, 189.459], 4);
Demo
Welcome to SO!
If your multi polygon is the blueish area, then I am afraid you have to refactor your data in order to achieve what you want (shifting the left area onto the right, as if it were stitched back to Russia main land).
Your data (probably GeoJSON?) contains a separate polygon which longitudes are in the [-180, -120] range. Leaflet has no choice but to display it on the left of your map, independently from the noWrap option.
So you would need to dig into your data, and add 360 degrees longitude to every node of this polygon, so that they now sit in the range [180, 300].
Or somehow introduce a "detection" in your code that would perform the longitude addition automatically for shapes which bounds and/or center are far away (let's say in the [-180, -120] longitude range). Leaflet does not perform that operation automatically out-of-the-box.
Note: the noWrap option is for your Tile Layer not to load tiles outside that "central" world (in order to avoid showing multiple copies of the world). But in your case, you want to show a part of Russia / Siberia on an "adjacent copy of the world", so you might want to remove that option, or you will have your polygon not sitting over any basemap.
when i am placing 5 pin on mapView with same address but callout bubble is shown only for two pin when the we taps a selected annotation view. When i tap pin then callout display only for two pins.
How to resolve this, i want to show callout of all pins even they have same address.
This happens because the zoomlevel of your map is not proper as per your coordinates requirements. Although you have annoted five pins at same address there should be minor difference into coordinates, to get separated.
You should work on longitudeDelta & latitudeDelta to get over this.
For ex. You can set
<coordinate_object>.latitudeDelta = 0.04;
<coordinate_object>.longitudeDelta = 0.04;
The lesser the delta value there is higher a zoom level and vice-a-versa.
Enjoy Programming!
Before adding each annotation to the map you should check if there is already another annotation at the same place, or within a few meters. If so then combine the data for these annotations into a structure that can keep growing (NSMutableArray is my first guess) and then add that combined data as a new annotation*. Then when the pin is tapped it will ask for the call out details and tell you which annotation was tapped, you can check if the annotation has one datum or multiple data at set up your callout correctly.
You'll need to have a custom annotation class but you would probably have needed that anyway if you're storing useful data about each one.
*you'll also need to ensure the first annotation is not left on the map, so maybe you could do a scan through your data and combine into arrays before doing any annotation stuff. Each annotation would store an array of values, most of them would only have one, but where they are too close together the array would have many values and your callout function would have to display that.
OK, here's the deal:
I have two views: simple and advanced. On the iPad, they come with a big-ass map view, with a marker that can be moved to indicate a position.
Each view has a different instance of MkMapView. When I switch from one to the other, I want to keep the map at exactly the same position and zoom level, so the user feels as if it is the same map.
However, the shape of the map view is slightly different for each of the views. This is because the advanced search has more stuff above the map.
When I open the map (this is code from an abstract superclass, so both instances get it), I set the region and marker position, like so:
[mapSearchView setRegion:[mapSearchView regionThatFits:[[BMLTAppDelegate getBMLTAppDelegate] searchMapRegion]]];
[myMarker setCoordinate:[[BMLTAppDelegate getBMLTAppDelegate] searchMapMarkerLoc]];
searchMapRegion and searchMapMarkerLoc are static, and reflect the currently displayed map's region and marker location (the center of the map).
Here's the problem:
Because the map is a slightly different shape, there is always a bit of adjusting. This can "bounce" back and forth, so that the map zoom keeps decreasing every time you switch, until you are looking at the whole world.
It doesn't matter whether or not I use regionThatFits. The same thing happens, even with this code:
[mapSearchView setRegion:[[BMLTAppDelegate getBMLTAppDelegate] searchMapRegion]];
[myMarker setCoordinate:[[BMLTAppDelegate getBMLTAppDelegate] searchMapMarkerLoc]];
All I want, is for the exact same zoom and center to be displayed. I don't care is the advanced view cuts a bit off.
How do I get the $##!! MapKit to stop tweaking the zoom factor?
Just FYI. I solved this by creating a custom model layer class that maintains the scale and center point, and is used by multiple MKMapViews. It works pretty well, but the MapKit does sometimes tweak the scale very slightly to fit one of its "detents."
I need to display on the map a scale showing how far a inch / cm is for example. This will need to change depending on the zoom level.
My theory is that if I know the length of the map, and the length of the graphic, If I know what the current scale of the map was I could just do some maths to work out the graphic indicator scale.
So is there a way to get the current zoom lvl in meters? Is it linked to the span or something?
The zoom level is linked to the span - you first need to get the span of your map view, and then convert it into meters.