openlayers-3 change external wms layer styles - css

Question

Is it possible change the style of a external wms layer??
im trying to use this layer:
https://firms.modaps.eosdis.nasa.gov/wms/?SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&LAYERS=fires24&width=400&height=250&BBOX=-26,34,35,82
with this code on openlayers3
var fill = new ol.style.Fill({color: 'GREEN'});
var stroke = new ol.style.Stroke({color: 'GREEN'});
var styles = [new ol.style.Style({
image: new ol.style.Circle({
fill: fill,
stroke: stroke,
radius: 5
})
})];
var fires = new ol.layer.Image({
name: 'fires',
source: new ol.source.ImageWMS({
url: 'https://firms.modaps.eosdis.nasa.gov/wms/',
params: {
'LAYERS': 'fires24',
'VERSION': '1.1.1'
}
}),
style: styles
});
the layer is displayed correctly but without my own styles.
Is it possible to do that or replace with a custom icon?

Answer 1

The WMS link you use is returning a PNG file, which I believe OpenLayers cannot style 'after the fact'. Once you've got it it's immutable - it's not 'data' but an image with transparency that is overlaid on top of your underlying map source.
There are some params you can pass into a wms call (as you've done) and the standard looks like it can support you passing styles into the call to the WMS server to get it to use those when rendering the image.
I've got a list of possible parameters from the geoserver website (a GIS server) - http://docs.geoserver.org/stable/en/user/services/wms/reference.html
Looking at that link it looks like sld or sld_body parameters may work. SLD is like OL styles but in XML. Details of these stylesheets are here - http://docs.geoserver.org/stable/en/user/styling/index.html#styling
I've had a go at this jsfiddle : https://jsfiddle.net/y7fj57dj/ but it's not working as such - it could either be my SLD (I'm not up to speed with it) or the NASA server doesn't know what to do with it/is ignoring it.
You may need to contact NASA server admins to confirm if you can style the WMS calls (support#earthdata.nasa.gov, retrieved by going to https://firms.modaps.eosdis.nasa.gov/wms/?SERVICE=WMS&VERSION=1.1.1&REQUEST=GetCapabilities).