I published a DEM data to Cesium Ion, and the terrain appears as a plateau rising from sea level.

[Yong_Shao]

I published a DEM data to Cesium Ion, and the terrain appears as a plateau rising from sea level.
I have processed the data in QGIS. I used the raster calculator with the expression ("dem_converted_int@1" > 2000) * "dem_converted_int@1" to complete the processing. Then, I used the command gdal_translate -a_nodata 0 -of GTiff dem_qgis.tif dem_qgis_nodata.tif to set the 0 values as NoData. After viewing the converted dem_qgis_nodata.tif in QGIS, I confirmed that the original 0 values have been changed to NoData, and the black border around the original DEM has disappeared.
thank you！