# Cartesian3 converting terrain **URL:** \ **Category:** CesiumJS\ **Created:** [January 24, 2022, 11:40am UTC](https://community.cesium.com/t/cartesian3-converting-terrain/17013 "2022-01-24T11:40:33Z")\ **Posts on this page:** 10\ **Page:** 1

**Author:** ![mcck](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/mcck/32/7425_2.png) [@mcck](https://community.cesium.com/u/mcck)\ **Post date:** [January 24, 2022, 11:40am UTC](https://community.cesium.com/t/cartesian3-converting-terrain/17013/1 "2022-01-24T11:40:33Z")

There is a Cartesian3 `{x: -1270054.670468495, y: 5643182.82695817, z: 2678382.5261573032}` It has no height. How to turn it into a high Cartesian3，It is similar to `heightReference: HeightReference.RELATIVE_TO_GROUND` set by entity？ Or entity is set to `heightReference: HeightReference.RELATIVE_TO_GROUND`, how to get the actual cartesian3？ ---

**Author:** ![sam.rothstein](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/sam.rothstein/32/6584_2.png) [@sam.rothstein](https://community.cesium.com/u/sam.rothstein)\ **Post date:** [January 25, 2022, 4:34pm UTC](https://community.cesium.com/t/cartesian3-converting-terrain/17013/2 "2022-01-25T16:34:40Z")

Hi @mcck! It was my understanding that the third coordinate in Cartesian3 represented elevation. Can you please share some more details on your high-level goals here? ---

**Author:** ![mcck](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/mcck/32/7425_2.png) [@mcck](https://community.cesium.com/u/mcck)\ **Post date:** [January 26, 2022, 5:14am UTC](https://community.cesium.com/t/cartesian3-converting-terrain/17013/3 "2022-01-26T05:14:33Z")

I want DOM to be positioned on a point。Unfortunately, the elevation of cartesian3 is 0，DOM is not positioned correctly ```auto

hello

``` ---

**Author:** ![lennart.imberg](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/lennart.imberg/32/9788_2.png) [@lennart.imberg](https://community.cesium.com/u/lennart.imberg)\ **Post date:** [January 26, 2022, 6:59am UTC](https://community.cesium.com/t/cartesian3-converting-terrain/17013/4 "2022-01-26T06:59:55Z")

Hey @sam.rothstein and @mcck , here is a picture what describes the xyz coordinates of cartesian. Their origin is the center of the earth: ![image](https://global.discourse-cdn.com/cesium/original/2X/c/ca569ed6c0e03ef9339e55a7cebfaf6025740794.jpeg) The solution is, just add the targeted height as 3rd parameter to `Cesium.Cartesian3.fromDegrees(...);` Best, Lennart ---

**Author:** ![mcck](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/mcck/32/7425_2.png) [@mcck](https://community.cesium.com/u/mcck)\ **Post date:** [January 26, 2022, 7:12am UTC](https://community.cesium.com/t/cartesian3-converting-terrain/17013/5 "2022-01-26T07:12:21Z")

But I don’t have the third parameter, elevation，Can it be calculated ---

**Author:** ![lennart.imberg](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/lennart.imberg/32/9788_2.png) [@lennart.imberg](https://community.cesium.com/u/lennart.imberg)\ **Post date:** [January 26, 2022, 7:31am UTC](https://community.cesium.com/t/cartesian3-converting-terrain/17013/6 "2022-01-26T07:31:11Z")

Oh, now I understand. Yes, it can be calculated from your Cartesian, but the one you provided in the first post has actually a height of 4.656612873077393e-10 so its ~0. Anyways, here is a Sandcastle link with height-calculation: [link](https://sandcastle.cesium.com/#c=bVLLbtswEPyVhU4y4FKi3pYdo61boEUD9NAguejCSIxMlCYFknZiB/n3kqJtOKlv2tmZndmldkTBjtFnquAGBH2GFdVsu0H3IxY2QTvWKykMYYKqJpjMG9GIKLLQjirNpIAnJTewIspYLhFg5FjIXpFhzVpX99TAmrJ+bRrBz9/W8mh3yUdu3Hla2AiA15caPuGkjOM8Q0UZZ0WVzfKpa8G+hrzIUlwlqEqKWV7h0jcONSRFWaW2kScFzss0TpO3RkyQd5+7LVoptOQUcdmHHvb7+ZjtKUX6PqrHxqDfaK8o1SGOY4TLHFdVls6saTaFJEcFLss0K9IZLrIsttjJA04Wg2TCHcI/AqLCMMOoRqTrwle3xyC1RaSoL9JMfcMqaxhJAK3kUtXnkK5CDz9+3n33x4CBvVD+hx1oDTg+YnJruH3U1RXp19svq1/vaQ+sM2urdqA945s/1DH3QcrNnQzHTJN5MA0W2uw5XfoJAJ/ZZpDKwFbxEKHI0M3Aid0mety2f6lBrdZunqMuokvpomM7YN3NlT8RWk60tp2nLR9Xa4LlIrL8/6Rcko6J/rf9YTnZO9oaL289iBBaRLa8rjRS8keiPkz+Bw) If you need heigth, either you need some source of height-information or set it to a random height. ---

**Author:** ![mcck](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/mcck/32/7425_2.png) [@mcck](https://community.cesium.com/u/mcck)\ **Post date:** [January 26, 2022, 7:46am UTC](https://community.cesium.com/t/cartesian3-converting-terrain/17013/7 "2022-01-26T07:46:15Z")

Maybe I can’t describe it clearly, but I may have found a way ```auto let cartographic = Cesium.Cartographic.fromCartesian(cartesian3); let longitude = Cesium.Math.toDegrees(cartographic.longitude); let latitude = Cesium.Math.toDegrees(cartographic.latitude); let height = viewer.scene.globe.getHeight(cartographic); let cartesian3Height = Cesium.Cartesian3.fromDegrees(longitude, latitude, height); ``` ```auto

hello

``` ---

**Author:** ![lennart.imberg](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/lennart.imberg/32/9788_2.png) [@lennart.imberg](https://community.cesium.com/u/lennart.imberg)\ **Post date:** [January 26, 2022, 7:57am UTC](https://community.cesium.com/t/cartesian3-converting-terrain/17013/8 "2022-01-26T07:57:58Z")

Thats indeed a viable solution! Be aware that terrain needs some time to load, so until it is loaded you will get `height = undefined` with this method. But as you put it in a EventHandler it should not be a problem in this case. Best Lennart ---

**Author:** ![mcck](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/mcck/32/7425_2.png) [@mcck](https://community.cesium.com/u/mcck)\ **Post date:** [January 27, 2022, 1:27am UTC](https://community.cesium.com/t/cartesian3-converting-terrain/17013/9 "2022-01-27T01:27:31Z")

OK, my problem has been solved. Thank you very much ---

**Author:** ![James\_B](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/james_b/32/2424_2.png) [@James\_B](https://community.cesium.com/u/James_B)\ **Post date:** [February 9, 2022, 11:18am UTC](https://community.cesium.com/t/cartesian3-converting-terrain/17013/10 "2022-02-09T11:18:32Z")

It sounds like you sorted this out but nobody explained the fundamental nature of the problem. Cartesian3 is for representing x/y/z coordinates in 3D space relative to the center of the earth. What you’re actually talking about is GPS coordinates on the surface of the earth. Cesium represents this concept with [Cartographic](https://cesium.com/learn/cesiumjs/ref-doc/Cartographic.html). Latitude and longitude are natively stored in radians (angle across the ellipsoid’s surface), but the structure is commonly constructed using `Cartographic.fromDegrees`. If you model your position using `Cartographic`, you can easily modify the altitude (above ellipsoid surface) by changing its `height` property. Cartographics can be converted to Cartesian3 using the static `Cartograhic.toCartesian` function.