如何缩放/移动相机以在Cesium.js中显示多边形（使视口适应多边形边界）

Question

Ok, maybe I'm blind because clearly this is not advanced functionality.. but I'm looking at the Camera docs for Cesium.js , and I can't seem to find how you simply zoom/move the view to show a polygon?

I can position the camera to show the poly using the mean lat/lon values, like:

viewer.camera.setView({
    position : Cesium.Cartesian3.fromDegrees(lonMean, latMean, 45000.0)
});

But that's rubbish; I don't get the zoom... I want the zoom/viewport to be adjusted to fit the polygon.

Can anybody point out what I must be overlooking...

Answer 1

Assuming you have a polygon defined in the Entity API, then you can simply call viewer.zoomTo(entity) or viewer.flyTo(entity) . This works with any type of entity visualization, not just polygons, and is discussed in Cesium's Visualizing Spatial Data tutorial .

Answer 2

Take a look at the Sandcastle Camera Demo . Pull-down the "Camera options" drop box, and select either "Fly to Rectangle" or "View a rectangle." The camera will fly or snap to the rectangle, and the code editor shows how this is done. Take a look through the other Sandcastle demos too, they contain lots of sample code for common actions in Cesium.

Here's the FlyTo code:

var west = -90.0;
var south = 38.0;
var east = -87.0;
var north = 40.0;
var rectangle = Cesium.Rectangle.fromDegrees(west, south, east, north);

viewer.camera.flyTo({
    destination : rectangle
});