I am trying to use draw feature of openlayer (polygon). It is possible for the end user to draw a polygon. But I want to draw the polygon through java script. I am trying to use insertXY and insertDeltaXY functions of openlayer, but there comes a js error "Object doesn't support property or method 'insertXY'".
Follow is my chunk of code.
var draw = new OpenLayers.Control.DrawFeature(
vectorLayer,
OpenLayers.Handler.Polygon }
);
map.addControl(draw);
draw.activate();
//Listen for sketch events on the layer
draw.layer.events.on({
featureadded: that.PolygonAdded
});
//Draw polygon if provided from codebehind
//Insert a point in the current sketch given x & y coordinates
handler.insertXY(cords[0], cords[1]);
//Insert a point given offsets from the previously inserted point.
handler.insertDeltaXY(cords[2], cords[3]);
handler.insertDeltaXY(cords[4], cords[5]);
.....
Any help is highly appreciated.
Try using the draw object to insert points. According to the OpenLayers documentation
the OpenLayers.Control.DrawFeature exposes the methods insertXY and insertDeltaXY. I don't know if your handler object has these methods.
//Insert a point in the current sketch given x & y coordinates
draw.insertXY(cords[0], cords[1]);
Related
I am developing a coloring game using adobe air and as3. I have an image with black outline and the user can draw / color the image using a pen tool. I need help to figure out how can I restrict the user to draw within the outlines only. Masking the image with the line-graphics is something I have tried but it hangs the application. Any hint / suggestion towards the solution is appreciated.
following is the code on mouse_down event
_dot = new MovieClip();
_dot.graphics.lineStyle(lineSize, color);
_dot.graphics.moveTo(img.mouseX,img.mouseY);
img.addChild(_dot);
Let's say, the area you are drawing on is a DisplayObject with an instance name of Canvas. What you need is to check if the mouse is on Canvas or not.
In order to do so, you want to use the DisplayObject.hitTestPoint(...) method with the shapeFlag set to true (if it is false, it tests the point against the object's rectangle bounding box, which would produce the wrong results for any non-rectangular or rotated shapes).
So, you do as following:
var P:Point = new Point;
// First, convert coordinates to Stage coordinates,
// because the method requires so.
P.x = Canvas.mouseX;
P.y = Canvas.mouseY;
P = Canvas.localToGlobal(P);
// Now, test if the mouse is within the given canvas.
if (Canvas.hitTestPoint(P.x, P.y, true))
{
// The drawing should happen here.
}
I'm trying to draw polygon on my map using ngmap. The map is displayed correctly as this example is showing, but when I finish the draw, this is what I'm getting:
ng-map.min.js:25 Uncaught TypeError: Cannot read property 'onMapOverlayCompleted' of undefined
I used the same code of the example.
My questions:
1- How can I solve this error?
2- If I want to let the user draw only polygon form, I have tried to set the value of drawingMode to "polygon" but I'm always having the other draw options (circle...). How can let only the polygon draw?
3- How can I let the user clear the drawn polygon?
4- Is it possible to detect the action of putting (drawing) every points. I mean that to draw a line in the polygon for example I need at least two points. Can I detect when the user draw the first point then the second and get its coordinates?
Edit
This is the whole error that I see when I include ng-map.js instead of ng-map.min.js :
Uncaught TypeError: Cannot read property 'onMapOverlayCompleted' of undefined
at index (http://localhost:8080/bower_components/ngmap/build/scripts/ng-map.js:2690:44)
at Array.reduce (native)
at Uw.<anonymous> (http://localhost:8080/bower_components/ngmap/build/scripts/ng-map.js:2691:39)
at P4._.z.trigger (https://maps.google.com/maps/api/js?key=MY_API_KEY&libraries=placeses,visualization,drawing,geometry,places:99:121)
at P4.<anonymous> (https://maps.google.com/maps/api/js?key=MY_API_KEY&libraries=placeses,visualization,drawing,geometry,places:37:81)
at C4._.z.trigger (https://maps.google.com/maps/api/js?key=MY_API_KEY&libraries=placeses,visualization,drawing,geometry,places:99:121)
at C4.<anonymous> (https://maps.google.com/maps/api/js?key=MY_API_KEY&libraries=placeses,visualization,drawing,geometry,places:37:81)
at Object._.z.trigger (https://maps.google.com/maps/api/js?key=MY_API_KEY&libraries=placeses,visualization,drawing,geometry,places:99:121)
at F4 (https://maps.google.com/maps-api-v3/api/js/28/14/drawing_impl.js:7:70)
at G4 (https://maps.google.com/maps-api-v3/api/js/28/14/drawing_impl.js:4:249)
Edit 2
I solved the first question:
My problem was that I'm using routes in the app.js. So the html and the controller are linked in it. To solve the problem, I put $scope.onMapOverlayCompleted instead of
var vm = this;
vm.onMapOverlayCompleted because I don't write the the ng-controller="DrawingManagerCtrl as vm" in my HTML. Then in the HTML I put on-overlaycomplete="onMapOverlayCompleted()" and it works.
I solved also the second question by using:
drawing-control-options="{position: 'TOP_CENTER',drawingModes:['polygon']}"
I'm want now to solve the other problems.
Any help please?
3
As the example you referenced shows, the overlaycomplete callback function receives e (Event) as the first parameter. This OverlayCompleteEvent object contains reference to the drawn overlay at Event.overlay (see docs of the original Google Maps JS API more info, since ng-map is only wrapper of the original API after all, specifically "OverlayCompleteEvent object specification" section).
Using that you can get the reference to the created overlay, store it and then later call .setMap(null) on it to delete it from map. E.g:
$scope.myDrawnOverlays = []; //array where you store drawn overlays
$scope.onMapOverlayCompleted(e){
...
myDrawnOverlays.push(e.overlay); //store reference to the drawn overlay after it's drawn
}
$scope.deleteAllDrawnOverlays(){
for(var i = 0; i < myDrawnOverlays.length; i++){
myDrawnOverlays[i].setMap(null); //remove overlays from map one by one
}
myDrawnOverlays = [];
}
Then whenever you want to delete all overlays, just call the function $scope.deleteAllDrawnOverlays (you can tie it to some button using ng-click or do whatever you want with it).
4
This is NOT possible using google.maps.drawing.DrawingManager which is used in your example. The reason is that DrawingManager doesn't support events for clicking at the map while drawing (see docs again for possible events, section "DrawingManager class").
So except hacky workarounds which could break any time with new api release, the only possible solution is to implement drawing of polygon yourself and not use DrawingManager. Check for example this SO answer, specifically the referenced example (right-clicks on map). They don't use ng-map, but basically what would you have to do is to add on-click="mapClickHandler" to your ng-map, in the mapClickHandler get position where you clicked on map, draw Marker there which would look like a dot and if you have more dots connect them with lines.
This is however too much for one question, you would have to probably read up on ng-map and relevant sections of Google Maps Js Api yourself.
I'm new to Geotools. I am developing a simple application that shows a map and I would like to dynamically place a bitmap or vector symbol on it (for example to show where the current position is, like in navigation systems).
Now, what I've done already is:
showing a map given one or more shapefile.
center the map on the last inserted position.
add shapes to new layers when needed.
What I need to do is to create an overlay with images at given coordinates on the map area (to be clear, I don't want to generate a raster layer on disk, I just want to paint on the screen).
My guess is that I have to somehow directly use the Graphics2D instance inside JMapPane, is that correct? In this case how can I convert from the geographic coordinates to pixel coordinates on the drawing pane? Or are there some geotools functions/classes that I should be looking for?
Thank you.
Answering myself, since I found the solution.
I did it by extending class org.geotools.map.DirectLayer, which provides a way to define a custom layer by extending its draw(Graphics2D, MapContent) method. Graphic elements are placed at the correct coordinates by using the worldToScreen affine transform provided by geotools. For example, to define a Point2D placed at the current position given real-world coordinates:
AffineTransform worldToScreen = viewport.getWorldToScreen();
Point2D worldPoint = new Point2D.Double(currentPosition.x, currentPosition.y);
Point2D screenPoint = worldToScreen.transform(worldPoint, null);
Once the draw() method is defined, just instantiate and add as a layer to your MapContent instance.
I have thousands of points that need to be plotted on google maps and got a very responsive maps using the example from https://github.com/ubilabs/google-maps-api-threejs-layer .
Did anyone have a play at this and wondering if it is possible to have different colored markers and possible marker click events?
Appreciate any pointers or examples online.
Millions of clickable data points can be painted on a google map using webgl.
A data point is represented by an x,y pair for a location on the canvas, an int for size, an off screen color, and an on screen color. These values are stored in separate typed arrays.
Each data point has a unique rgb color to act as a key in a lookup table of data point ids.
Create a texture to store the off screen colors and render it to an off screen buffer. On event, load the off screen buffer and use glReadPixels to retrieve the rgb color of the pixel clicked and then find the id in the lookup table. Points on the on screen buffer, what the user sees, can share a common color.
canvas.addEventListener('click', function(ev) {
# insert code to get mouse x,y position on canvas
pixels = new Uint8Array(4);
gl.bindFramebuffer(gl.FRAMEBUFFER, framebuffer);
gl.readPixels(x, y, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, pixels);
gl.bindFramebuffer(gl.FRAMEBUFFER, null);
if (colorToId[pixels[0] + " " + pixels[1] + " " + pixels[2]]) {
# Pixel clicked is a data point on the map
}
});
Webgl code is lengthy, so only the click event is included.
Here is a live demo and a repo. (angular and coffeescript)
Here is a second example using plain js: webgl-picking-geo-polygons
Here is react-webgl-leaflet
The solution is based on Brendan Kenny's Google Maps + HTML5 + Spatial Data Visualization which explains some of the code in the excerpt above at the 30 min mark, and Displaying WebGL data on Google Maps.
The demo features less than ten data points, but you can just as easily paint over 16 million pickable data points using all combinations of rgb values.
I discovered OpenLayers this past week. Very, very impressive framework. I would strongly suggest taking a look at it. OpenLayers.org is an open source JavaScript web mapping library distinguished from other alternatives, like Leaflet or Google Maps APIs, because of its huge set of components.
I spent the entire weekend creating sample apps by integrating OpenLayers with API's such as MapBox, WebGL etc... After all was said and done, I was extremely impressed with OpenLayers - and I plan to make use of OpenLayers in an upcoming POC/Project.
Here is a link to my test harness. From there you can also download the code for all of the examples, too.
Updates for 2021!!
Google Maps JS now has a WebglOverlayView class and exposes the WebGL context.
const webglOverlayView = new google.maps.WebglOverlayView();
webglOverlayView.onAdd = () => {
// Do setup that does not require access to rendering context.
}
webglOverlayView.onContextRestored = gl => {
// Do setup that requires access to rendering context before onDraw call.
}
webglOverlayView.onDraw = (gl, coordinateTransformer) => {
// Render objects.
}
webglOverlayView.onContextLost = () => {
// Clean up pre-existing GL state.
}
webglOverlayView.onRemove = () => {
// Remove all intermediate objects.
}
webglOverlayView.setMap(map);
Additionally, #googlemaps/three extends this class for easier use with ThreeJS.
// instantiate a ThreeJS Scene
const scene = new Scene();
// Create a box mesh
const box = new Mesh(
new BoxBufferGeometry(10, 50, 10),
new MeshNormalMaterial(),
);
// set position at center of map
box.position.copy(latLngToVector3(mapOptions.center));
// set position vertically
box.position.setY(25);
// add box mesh to the scene
scene.add(box);
// instantiate the ThreeJS Overlay with the scene and map
new ThreeJSOverlayView({
scene,
map,
});
Here is a link to a jQuery/google map app. Not exactly what you are looking for; however you might find the example useful. Feel free to use - it can be downloaded from my site.
Link to app on my website
Click here to download the zip
How do I update my Elevation Object when I change the bimapdata of its height map?
I noticed that getHeightAtPosition() updates to the values of the new bitmap, but the Elevation still looks the same..
(I know it is possible to loop through all vertices in the geometry mesh and adjust them based on the bitmap, but the nice thing with Elevation is that you don't have to do that. If it can adjust to the bitmap on creation it should be able to update..)
Ok, I found the answer on the away 3D forum:
http://away3d.com/forum/viewthread/1110/#3808
Basically, you need to change one line in the Elevation class:
Go to elevation.as and change
private function updateGeometry()
to
public function updateGeometry()
then on the render after you change the parameters call
_elevation.updateGeometry();