How to remove spikes in a raster/DEM

[WinnieLau]

This is an oblique view of a lake and the red circle showing a spike in the DEM. 

How to remove the spikes?

I use a DEM and drape the image on it in ArcScene.

I have ArcGIS Desktop Advanced + 3D Analyst

Thanks!

[DanPatterson_Retired]

Strange...how did the DEM get the spike in the middle of the lake in the first place?

If the lake has a constant elevation  (no​ assumptions here) you could assign the elevation to the DEM if you had the spatial analyst extension using the Con tool

[WinnieLau]

Thanks Dan.  I don't have Spatial Analyst.  How can I assign or fix the spike? 

[DanPatterson_Retired]

​You need the spatial analyst or its open source equivalent

[PrasantaBhattarai · Accepted solution]

Hello!

You can request free evaluation license of ArcGIS Spatial Analyst if necessary. However, you can also replace the values of the elevation surface by mosaicking a constant raster with existing surface.

Here's what could be done.

- If you know constant value and the area(lake boundary for example) you can create a raster with constant elevation value by converting polygon to raster. You can use original elevation raster for cell size and snapping.

- Once you have the constant raster created, you can mosaic the two together. Make sure you select correct parameter for pixel type, number of bands, and mosaic operator.

Hope this helps.

Thank you,

Prasanta.

[SepheFox]

Great idea, Prasanta!

[WinnieLau]

Very good idea.  It's a good alternatives when I don't have Spatial Analyst.  I've already asked for the free trial once so I don't think they would give me another one

Thanks for your time Prasanta!

[WinnieLau]

Prasanta, I tried and it works! 

Thanks a lot!