I'm trying to put all the currently visible Placemarks on the map into an array. What's the correct way of getting all the placemarks on the map that are visible?
I'm stuck on trying this type of method, but it's far from correct
var mapSize = YandexMap.action._map._containerSize;
var rectangle = new ymaps.Rectangle([[0, 0], [mapSize[0], mapSize[1]]);
YandexMap.geoObjects.add(rectangle);
Related
I am using GMap.NET to display a lot of Marker (about more than 10.000 markers). R-Tree is a solution to optimize render markers at area which window is showing.
STRtree in NetTopologySuite is a library to support R-tree. But I'm not sure it suitable for this problem.
My question is how to use R-Tree in NetTopologySuite to show markers. I don't know how to use library. (I'm new in WPF). How to catch event when GMap render marker to get marker from R-Tree and remove previous marker at same time?
Please give me some example about R-tree in NetTopologySuite.
I did it by my way. This is the way STRtree is decleared: STRtree<Coordinate> gpsSTRtree = new STRtree<Coordinate>(); You can change Coordinate data type by any other data type but STRtree need to Envelope to insert to tree.
For example: insert to STRtree:
Coordinate gps = new Coordinate(9.74233, 106.0213);
Envelope item = new Envelope(gps);
gpsSTRtree.Insert(item, gps);
Envelope is a node in STRtree to store the boundary of item.
STRtree query from two points. point1 and point2 are Coordinate
Envelope gpsQuery = new Envelope(p1, p2);
Coordinate gpsItems = gpsSTRtree.Query(gpsQuery);
Then you have a list of Coordinate
Good luck
I am using this react masonry component
I am displaying my masonry tiles from a filtered array.
var myFilteredArray = myArray.filter( (tile) => this.props.filter.indexOf(tile.tag) > -1 )
var tiles = myFilteredArray.map( (tile) => <MyTile/>)
Where myArray is an array of json objects with a tag field. props.filter is an array of strings.
For exampleprops.filter = ["a","b","c"] and the json tags are "a", "b", "c"
When I update my props filter so that props.filter = ["b"]
I see that the A and C objects disappear and object B moves to the left most of the container.
However when I add back tags "a" and "c" into props.filter, the objects show up in the wrong position.
I would expect that the objects be in the order A,B,C, and filling up the container from the left most. What I see however is that object B goes back to where it was originally, and A, and C show up either on top of it or to the right of is. That means there is a big empty space to the left of Object B
My question is why is this happening? And how do I fix this?
It's kinda hard to be sure without more info, but this smells like a list of components that are missing a key attribute. Try something like
var tiles = myFilteredArray.map( (tile) => <MyTile key={tile.tag}/>)
Reference.
As per #mattclemens suggested, it may be a problem with the algorithm for where things are placed.
It looks like this is already recorded here:
https://github.com/eiriklv/react-masonry-component/issues/11
The hacky solution is to put a dummy div first that has 1 width and 0 height in pixel (or vice versa).
I am new to leafletjs. I am working on a map that renders just the united states map with few layers options such as roads and major roads ecc.. I have a base layer that uses WMS protocol to get the first layer's tiles with the following code:
L.tileLayer.wms(......)
Then I have another layer that comes from a different server which does not use WMS protocol. This server accepts parameters like bbox, height, width, lat, lng and few others. I can query this server for one tile at a time, so i need to provide multiple ajax calls to get multiple tiles to cover my current view and also update all layers when the map is moved.
The problem I have is how to make both layers work together? and how to get the Bounding Box of each tile the leafletJS way? and how to continue to update all tiles on "moveend" event as the user moves the map?
Using version 0.7.3 of leafletJS!
Thanks for your help
There is undocumented function in L.TileLayer class:
L.TileLayer.getTileUrl(tilePoint)
This function is called for each tile on a screen. It receives hash with x, y and z keys (tile number) and returns image URL for the tile. You can rewrite this function in your L.TileLayer instance:
var layer = L.tileLayer(url);
layer.getTileUrl = function(tilePoint) {
return 'http://example.com/' + tilePoint.z + '/' + tilePoint.y + '/' + tilePoint.x + '.png';
}
So, you don't need to track map movements, appearing and disappearing of tiles, etc.
My map (Mapbox) takes up the whole background of the site so the center is in the middle of the site. But the focus of the map for the user is on the right side because I have content overlapping the map on the left side. When leaflet grabs the location, it's from the center of the map, but it would be more convenient if I could set it to grab the location from the center of the right third of the site, so that way the user won't be centering the map on targets bordering content on the left half of the site.
Is there a way I could set the center or location focus of the leaflet API for the map?
Here's how I have it set up currently,
mapOptions: {
maxZoom: 18,
zoomControl: false,
worldCopyJump: true
},
createMap: function() {
Map.map = L.map('map', Map.mapOptions);
Map.layer = L.mapbox.tileLayer(Map.mapID, {
unloadInvisibleTiles: true,
}).addTo(Map.map);
Map.map.locate({setView: true});
Map.map.addControl(L.mapbox.geocoderControl(Map.mapID));
new L.Control.Zoom({ position: 'topright' }).addTo(Map.map);
},
You can use a combo of panBy() and getSize() to offset the map the width of your overlay.
Here's a snippet that should get you a started:
// Calculate the offset
var offset = map.getSize().x*0.15;
// Then move the map
map.panBy(new L.Point(-offset, 0), {animate: false});
In my example, my overlay is 33% of the width of the map. So I grab the size of the map area, then multiple by 0.15 (this was based on some experimenting to see what the best offset amount was) and use panBy() to offset the map center.
Here's a full example.
If you have multiple markers and want to center the map in their bounds and at the same time you have overlapping container, you can use the fitBounds options (paddingTopLeft, paddingBottomRight, padding).
http://leafletjs.com/reference.html#map-paddingtopleft
First you will need to know the lat and long of the point on the map you want to center on. Then it is simple, just call Map.map.setView passing in your coordinates and zoom level.
Api reference: http://leafletjs.com/reference.html#map-set-methods
If you don't know your coordinates then you can find it by trial and error, just create a marker and add it to the map.
Found this solution by ghybs over on GIS which helped me solve this problem:
Leaflet-active-area
This plugin allows you to use a smaller portion of the map as an active area. All positioning methods (setView, fitBounds, setZoom) will be applied on this portion instead of the all map.
I am programming a basic GUI in MATLAB that utilizes the mapping toolbox. The GUI will display a grayscale image and then plot discrete points over the data, all of this over the necessary map projection. It is important that I plot onto map axes (those created by the axesm command) rather than the vanilla cartesian space. I have no problem doing all this from the command line, but I cannot find a way to implement a GUI version and its driving me nuts.
The problem is that I need to specify the map axes as being the child of the parent figure. The normal axes has a property that can be set, doing something like:
axesHandle = axes('Parent', parentHandle, ...);
or
set(axesHandle, 'Parent', parentHandle);
However, there is no equivalent parent property for the map axes created by the axesm function, so I have no way to manipulate the axes within the figure. How can I do this?
Update: If I create a plot within the map axes in an empty figure, get(figureHandle, 'Children') returns the handle of the axesm object (thanks #slayton!), so the map axes object must be implicitly added to the children of the figure by MATLAB.
Should I be concerned that the map axes do not refer back to the parent figure, or should I just let it be? I wonder if this is a classic case of MATLAB forcing me to not comply with the standards the manual tells me to implement.
From reading your question what I think you are trying to do is grab the handle of the axes object. This can be done as the axes is created using either axes or subplot
a = axes();
a = subplot(x,y,z);
% both return an handle to the newly created axes object
Additionally if the axes is created automagically by a function call like plot or image you can get the axes handle that too:
p = plot(1:10); %returns a handle to a line object
a = get(p,'Parent');
i = image(); %returns a handle to an image object
a = get(i, 'Parent');
Finally, neither of those two options is available you can always get the axes handle from its containing figure with:
a = get(figureHandle, 'Children');
Remember though that this will return a vector of axes handles if your figure contains more than one axes.
Finally when it comes time to draw draw your points to the axes that contains your map image you simply need to call:
line(xPoints, yPoints, 'linestyle', 'none', 'marker', '.', 'color', 'r', 'size', 15)
This will draw the vertices of the line using large red dots.
I'm not sure if this answers your question because the code you provided doesn't line up with the question you asked.
The code you provided looks like you are trying to move an axes from one figure to another. You can totally do this!
f = figure('Position', [100 100 100 100]);
a = axes('Parent', f);
pause
f2 = figure('Position', [250 100 100 100]);
set(a,'Parent', f2);
After much trial and error and reading of documentation, I have found that there is no way to explicitly specify the parent of the map axes. Instead, they are implicitly added on top of the current axes. In the instance that no axes exist in the current figure, calling axesm creates an axes object and then places the axesm object inside. When you take this route, you have to grab the axes object handle by calling gca:
mapAxesHandle = axesm(...);
axesHandle = gca(...);
This makes it frustrating to use the mapping toolbox when writing a GUI from scratch, but that's the way Mathworks makes it happen. Thanks to #slayton for useful info. I'd upvote but my reputation is <15 :(