# How does turning off the DSM affect the orthomosaic?

**URL:** <https://community.pix4d.com/t/how-does-turning-off-the-dsm-affect-the-orthomosaic/26313>\
**Category:** PIX4Dmapper Questions/Troubleshooting\
**Created:** [May 3, 2023, 2:16pm UTC](https://community.pix4d.com/t/how-does-turning-off-the-dsm-affect-the-orthomosaic/26313 "2023-05-03T14:16:13Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![william.alexander](https://avatars.discourse-cdn.com/v4/letter/w/aca169/32.png) [@william.alexander](https://community.pix4d.com/u/william.alexander)\
**Post date:** [May 3, 2023, 2:16pm UTC](https://community.pix4d.com/t/how-does-turning-off-the-dsm-affect-the-orthomosaic/26313/1 "2023-05-03T14:16:13Z")

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For our workflow, we do not need our orthomosaics to carry elevation values (other programs we use will create their own DSM from the point cloud that they will “drape” the ortho over).

Therefore I have turned off DSM generation in the past to save processing time (it is a significant savings). I have not noticed either a quantitative or qualitative difference for our purposes, but recently I have been told that the DSM is used for more than applying elevation values in the ortho. However, nobody can tell me what exactly the DSM is used for besides elevation values and the help articles are vague (just saying that a noisy DSM creates anomalies in the ortho).

So what, exactly, is the DSM used for when generating the ortho, given that it is possible to generate the ortho without it?

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**Author:** ![Daniele\_Lecci](https://sea2.discourse-cdn.com/pix4d/user_avatar/community.pix4d.com/daniele_lecci/32/9493_2.png) [@Daniele\_Lecci](https://community.pix4d.com/u/Daniele_Lecci)\
**Post date:** [May 25, 2023, 12:36pm UTC](https://community.pix4d.com/t/how-does-turning-off-the-dsm-affect-the-orthomosaic/26313/2 "2023-05-25T12:36:12Z")

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Hi @william.alexander,

Welcome to the Pix4D Community 🤝.

The DSM (created from the Densified Point Cloud) is used in the Orthomosaic generation step in order to create a true orthophoto (in opposition to simple photo stitching). This method removes the perspective distortions from the images using the DSM.

You can find more information in this article:

> **[Photo stitching vs orthomosaic generation](https://support.pix4d.com/hc/en-us/articles/202558869-Photo-stitching-vs-orthomosaic-generation)**
>
> Photo stitching
> Orthomosaic
> 
> 
> 
> Photo stitching
> The photo stitching method glues images together and requires a low number of matches/keypoints (less than 100). It works well only if the terrain is ...