OpenLayers setting position of overlay on a static image - openlayers-3

I have created a map with OpenLayers 3 using static image. It uses fake projection so the map can use to properly display the layer as it's measured in pixels. This is the code:
var pixelProjection = new ol.proj.Projection({
code: 'pixel',
units: 'pixels',
extent: [0, 0, 1389, 1070]
});
var map = new ol.Map({
layers: [
new ol.layer.Image({
source: new ol.source.ImageStatic({
url: 'http://s25.postimg.org/4o15oqbmn/jdgf.jpg',
imageSize: [1389, 1070],
projection: pixelProjection,
imageExtent: pixelProjection.getExtent()
})
})
],
target: 'map',
view: new ol.View2D({
projection: pixelProjection,
center: ol.extent.getCenter(pixelProjection.getExtent()),
zoom: 2
})
});
I was trying to add marker overlays to add some more interactions however I'm struggling to specify position and the markers is outside the map rather then inside where I want to place it.
var marker = new ol.Overlay({
position: [200, 200],
element: document.getElementById('marker'),
stopEvent: false
});
I'm very novice to this so if anyone have an idea how to set position correctly I will be thankful.

Using this OpenLayers 3 map as an example, I was able to add a marker to the center of your static image with the following:
var iconFeature = new ol.Feature({
geometry: new ol.geom.Point([700, 700])
});
var iconStyle = new ol.style.Style({
image: new ol.style.Icon({
src: 'http://ol3js.org/en/master/examples/data/icon.png'
})
});
iconFeature.setStyle(iconStyle);
var vectorSource = new ol.source.Vector({
features: [iconFeature]
});
var vectorLayer = new ol.layer.Vector({
source: vectorSource
});

Related

OL3 Color Icon in KML

Now I am trying to migrate Google Earth to OpenLayers 3 (version 3.11.1)
I use a KML file, while viewing with GE, the icon is colored but with OL3, the color is not displayed
Here is my code snippet to post this KML file:
var projection = ol.proj.get('EPSG:3857');
var raster = new ol.layer.Tile({
source: new ol.source.BingMaps({
imagerySet: 'Aerial',
key: 'Ak-dzM4wZjSqTlzveKz5u0d4IQ4bRzVI309GxmkgSVr1ewS6iPSrOvOKhA-CJlm3'
})
});
var vector = new ol.layer.Vector({
source: new ol.source.Vector({
url: '/UsersFiles/KMLTest.kml',
format: new ol.format.KML({ extractStyles: true })
})
});
var map = new ol.Map({
layers: [raster, vector],
target: document.getElementById('map4'),
view: new ol.View({
center: [0 ,0],
projection: projection,
zoom: 0
})
});
the result is on the image below:
Icon in Google Earth
Icon in OL3

WFS layer not displayed in OL3 when loading as GeoJSON from geoserver

I am trying to load my layer from Geoserver as WFS layer in my OL3 application.
Here is my code to create WFS layer:
var vectorSource = new ol.source.Vector({
format: new ol.format.GeoJSON(),
url: function(extent, resolution, projection) {
return 'http://localhost:8080/geoserver/wfs?service=WFS&' +
'version=1.0.0&request=GetFeature&typename=main:Building_WGS&' +
'outputFormat=application/json&srsname=EPSG:4326&';
},
strategy: ol.loadingstrategy.tile(ol.tilegrid.createXYZ({
}))
});
var vector1 = new ol.layer.Vector({
source: vectorSource,
style: new ol.style.Style({
stroke: new ol.style.Stroke({
color: 'rgba(0, 0, 255, 1.0)',
width: 2
})
})
});
To make my code complete here is the code where I have created map object:
var centerpos = [84.2, 28.2];
var newpos = ol.proj.transform(centerpos,'EPSG:4326','EPSG:900913');
var maxExtent = [80.05844110726194,26.34796712822462,88.2015218371264,30.44742963310623];
var map = new ol.Map({
layers: [baseLayerOSM, vector1],
target: 'map',
//controls: [new CustomControl()],
view: new ol.View({
extent:ol.proj.transformExtent(maxExtent, 'EPSG:4326', 'EPSG:900913'),
projection : 'EPSG:900913', // OSM projection
center : newpos,
minZoom:7,
zoom: 7
})
});
I can see the OSM layer in my map. But I can't see the layer Building_WGS. I have a workspace main in geoserver.
When I copy the URL
'http://localhost:8080/geoserver/wfs?service=WFS&' +
'version=1.0.0&request=GetFeature&typename=main:Building_WGS&' +
'outputFormat=application/json&srsname=EPSG:4326&';
I can see the JSON contents.
Can anyone suggest what am I doing wrong in my code?
I even tried to add crossOrigin:"Anonymous" but that doesn't help either.
HELP please
AJ

How to add markers on OpenLayers 3 giving coordinates

I need to add a marker on my map when I call the method addMarker(long, lat).
The only example I have found is this one in the OpenLayers example list, but it adds only one marker in a specific place.
I need to be able to call my method anytime I need and pass the coordinates (the general idea is to have a simple menu where the user can type the long and lat and click a submit button and the marker is drawn on the map).
In the example, if I got it right, they created a feature and its style, then created a layer to draw the icon and initialized the map using that layer.
var iconFeature = new ol.Feature({
geometry: new ol.geom.Point(ol.proj.transform([-72.0704, 46.678], 'EPSG:4326', 'EPSG:3857')),
name: 'Null Island',
population: 4000,
rainfall: 500
});
var iconStyle = new ol.style.Style({
image: new ol.style.Icon(/** #type {olx.style.IconOptions} */ ({
anchor: [0.5, 46],
anchorXUnits: 'fraction',
anchorYUnits: 'pixels',
opacity: 0.75,
src: 'data/icon.png'
}))
});
iconFeature.setStyle(iconStyle);
var vectorSource = new ol.source.Vector({
features: [iconFeature]
});
var vectorLayer = new ol.layer.Vector({
source: vectorSource
});
var map = new ol.Map({
layers: [new ol.layer.Tile({ source: new ol.source.OSM() }), vectorLayer],
target: document.getElementById('map'),
view: new ol.View2D({
center: [0, 0],
zoom: 3
})
});
I believe I can create an array of features, something like that(an example I saw here):
var iconFeatures=[];
var iconFeature = new ol.Feature({
geometry: new ol.geom.Point(ol.proj.transform([-72.0704, 46.678], 'EPSG:4326',
'EPSG:3857')),
name: 'Null Island',
population: 4000,
rainfall: 500
});
var iconFeature1 = new ol.Feature({
geometry: new ol.geom.Point(ol.proj.transform([-73.1234, 45.678], 'EPSG:4326',
'EPSG:3857')),
name: 'Null Island Two',
population: 4001,
rainfall: 501
});
iconFeatures.push(iconFeature);
iconFeatures.push(iconFeature1);
Here is my method so far:
class map{
private markerFeatures = [];
//receive an array of coordinates
public addMarkers(markers: Array<Marker>): void {
for (var i in markers) {
var markFeature = new ol.Feature({
geometry: new ol.geom.Point(ol.proj.transform([markers[i].long, markers[i].lat], 'EPSG:4326',
'EPSG:3857')),
name: 'Null Island',
population: 4000,
rainfall: 500
});
this.markerFeatures.push(markFeature);
}
}
}
But nothing happened when I did that.
Obs: I created the map, the layer and called the method.
I'm using OL v3.7
Assuming you have a layer containing a vector source, you just need to add one more step to your addMarkers function:
myVectorSource.addFeatures(markerFeatures);

How to set zoom and center automatically based on GeoJSON features

I load some features from .json file, and would like to automatically set view wuth zoom to see all loaded features. I user OpenLayers version 3.
Here's what I have:
var gjsonFile = new ol.layer.Vector({
source: new ol.source.GeoJSON({
url: 'map.json',
projection: 'EPSG:3857'
})
})
});
var map = new ol.Map({
view: new ol.View({
center: ol.proj.transform([-77.0087,38.8691], 'EPSG:4326', 'EPSG:3857'),
zoom: 12
}),
layers: [
new ol.layer.Tile({
source: new ol.source.OSM()
}),
gjsonFile
],
target: 'map1'
});
Vector sources have a #getExtent() method that gives you the extent of all features currently loaded in the source. To set the map's view to that extent as soon as the file is loaded, add the following code:
var source = gjsonFile.getSource();
var onChangeKey = source.on('change', function() {
if (source.getState() == 'ready') {
source.unByKey(onChangeKey);
map.getView().fitExtent(source.getExtent(), map.getSize());
}
});

Feature doesn't show up on the map

I've been trying the new version (3) of Open Layers. I've modified the icon feature example slightly, so it would show a polygon. I've been searching, reading and trying for a couple of hours, but can't figure out what I'm doing wrong.
I don't want to use geoJSON, because I want to dynamically add and remove features.
This is the code I have so far:
<script type="text/javascript">
var point1 = ol.proj.transform([37.41, 8.82], 'EPSG:4326', 'EPSG:3857');
var point2 = ol.proj.transform([35.41, 9.82], 'EPSG:4326', 'EPSG:3857');
var point3 = ol.proj.transform([33.41, 11.82], 'EPSG:4326', 'EPSG:3857');
var polyFeat = new ol.Feature({
geometry: new ol.geom.Polygon([point1, point2, point3])
});
var polyStyle = new ol.style.Style({
fill: new ol.style.Fill({
color: 'blue'
}),
stroke: new ol.style.Stroke({
color: 'red',
width: 2
})
});
polyFeat.setStyle(polyStyle);
var vectorSource = new ol.source.Vector({
features: [polyFeat]
});
var vectorLayer = new ol.layer.Vector({
source: vectorSource
});
var rasterLayer = new ol.layer.Tile({
source: new ol.source.TileJSON({
url: 'http://api.tiles.mapbox.com/v3/mapbox.geography-class.jsonp'
})
});
var map = new ol.Map({
layers: [rasterLayer, vectorLayer],
target: document.getElementById('map'),
view: new ol.View({
center: ol.proj.transform([37.41, 8.82], 'EPSG:4326', 'EPSG:3857'),
zoom: 3
})
});
</script>
Why is the polygon not showing?
Two small things to solve your issue:
First, it's recommended to close a polygon, so declare a fourth point with same coordinates as the first.
var point4 = ol.proj.transform([37.41, 8.82], 'EPSG:4326', 'EPSG:3857');
Then, your geometry new ol.geom.Polygon([point1, point2, point3]) should be new ol.geom.Polygon([[point1, point2, point3, point4]])
The important fact here is not the point4 addition but to transform your array point to an array of array of points. See the API that says OpenLayers 3 ol.geom.Polygon constructor expects an Array.<Array.<ol.Coordinate>> expected.

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