# What height options to select for CesiumIon terrain upload?

**URL:** <https://community.cesium.com/t/what-height-options-to-select-for-cesiumion-terrain-upload/14422>\
**Category:** Cesium ion\
**Created:** [July 14, 2021, 5:35pm UTC](https://community.cesium.com/t/what-height-options-to-select-for-cesiumion-terrain-upload/14422 "2021-07-14T17:35:27Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Tunmise](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/tunmise/32/3458_2.png) [@Tunmise](https://community.cesium.com/u/Tunmise)\
**Post date:** [July 14, 2021, 5:35pm UTC](https://community.cesium.com/t/what-height-options-to-select-for-cesiumion-terrain-upload/14422/1 "2021-07-14T17:35:27Z")

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Hi there,

I’m trying to upload a terrain DTM file into Cesium ION. There’s an additional step in the upload process where I need to select some height options(Height Unit and Height Reference):

![Screenshot 2021-07-14 at 18.33.36](https://global.discourse-cdn.com/cesium/original/2X/9/9b5c17f3625f6eb4618ad45335efb640f8c9e319.png)

From the info section I see this:

![Screenshot 2021-07-14 at 18.25.39](https://global.discourse-cdn.com/cesium/original/2X/8/89943c409dcc95f5677d3b6140155d799b525750.png)

However, I don’t know how to determine the unit of measurement and the reference surface from the source (the DTM file) and this is where I need help. Do I need to do something to figure the Height Unit and Height Reference or I can just select any of the provided values and everything still works fine?

PS: I’m new to the geospatial world so this might be a total noob question but please I need help.

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**Author:** ![Matt\_Boyd-Surka](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/matt_boyd-surka/32/5511_2.png) [@Matt\_Boyd-Surka](https://community.cesium.com/u/Matt_Boyd-Surka)\
**Post date:** [July 14, 2021, 9:00pm UTC](https://community.cesium.com/t/what-height-options-to-select-for-cesiumion-terrain-upload/14422/4 "2021-07-14T21:00:53Z")

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Hi @Tunmise, I recommend you check the Coordinate Reference System (CRS) of the data using [QGIS](https://www.qgis.org/en/site/). Load the data into QGIS and then check Project ► Properties… ► CRS.

Once you know the CRS and height reference using QGIS, you can set the options accordingly in ion.

Further reading: [8. Coordinate Reference Systems — QGIS Documentation documentation](https://docs.qgis.org/3.16/en/docs/gentle_gis_introduction/coordinate_reference_systems.html)