# DTM for Mapping

**URL:** <https://community.pix4d.com/t/dtm-for-mapping/5924>\
**Category:** PIX4Dmapper Questions/Troubleshooting\
**Created:** [February 2, 2018, 12:11pm UTC](https://community.pix4d.com/t/dtm-for-mapping/5924 "2018-02-02T12:11:19Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![MYINT\_NAING](https://avatars.discourse-cdn.com/v4/letter/m/db5fbb/32.png) [@MYINT\_NAING](https://community.pix4d.com/u/MYINT_NAING)\
**Post date:** [February 2, 2018, 12:11pm UTC](https://community.pix4d.com/t/dtm-for-mapping/5924/1 "2018-02-02T12:11:19Z")

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Hello, Admin

&nbsp;

I want to known the how to remove Noise data Such as. tree, building and forest area for producing DTM.

Myint Naing

MD

GAI

myanmar

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**Author:** ![Selim\_Erguden](https://sea2.discourse-cdn.com/pix4d/user_avatar/community.pix4d.com/selim_erguden/32/337_2.png) [@Selim\_Erguden](https://community.pix4d.com/u/Selim_Erguden)\
**Post date:** [February 2, 2018, 2:47pm UTC](https://community.pix4d.com/t/dtm-for-mapping/5924/2 "2018-02-02T14:47:40Z")

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Hey Myint,&nbsp;

Try to add manual tie points where there is a noise. It should improve the quality of your DTM.

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**Author:** ![Pierangelo\_Rothenbuhler](https://sea2.discourse-cdn.com/pix4d/user_avatar/community.pix4d.com/pierangelo_rothenbuhler/32/2439_2.png) [@Pierangelo\_Rothenbuhler](https://community.pix4d.com/u/Pierangelo_Rothenbuhler)\
**Post date:** [February 5, 2018, 10:20am UTC](https://community.pix4d.com/t/dtm-for-mapping/5924/3 "2018-02-05T10:20:17Z")

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Hi Myint,&nbsp;

Trees, buildings and dense vegetation areas can be removed from the point cloud with the automatic point cloud classification or with the point cloud editing tool. These two articles describe these procedures in more detail:&nbsp;&nbsp;  
[How to automatically generate a Digital Terrain Model (DTM)  
 ](https://community.pix4d.com/hc/en-us/search/click?data=BAh7CjoHaWRpBEPUEgw6CXR5cGVJIgxhcnRpY2xlBjoGRVQ6CHVybEkiXC9oYy9lbi11cy9hcnRpY2xlcy8yMDI1NjA1NzktSG93LXRvLWF1dG9tYXRpY2FsbHktZ2VuZXJhdGUtYS1EaWdpdGFsLVRlcnJhaW4tTW9kZWwtRFRNLQY7B1Q6DnNlYXJjaF9pZEkiKTU5YmUwMGEyLTA3NzUtNGQxOS1hOWIyLTVmNjE5NjUxNDQwMgY7B0Y6CXJhbmtpDg%3D%3D--ec660d36c90ba348c216bd1dd2251cac27278d70)[How to edit the point cloud in the rayCloud](https://community.pix4d.com/hc/en-us/search/click?data=BAh7CjoHaWRpBPPTEgw6CXR5cGVJIgxhcnRpY2xlBjoGRVQ6CHVybEkiTS9oYy9lbi11cy9hcnRpY2xlcy8yMDI1NjA0OTktSG93LXRvLWVkaXQtdGhlLXBvaW50LWNsb3VkLWluLXRoZS1yYXlDbG91ZAY7B1Q6DnNlYXJjaF9pZEkiKTExOWU0OTY4LTgzMzUtNDVjYS04ZjA5LTExZWY3Mjk4Y2Q2OAY7B0Y6CXJhbmtpCQ%3D%3D--55119186e1e97bcfe47820f51aa5faf66a63277e)

There is also a video about how to generate the DTM: [https://www.youtube.com/watch?v=NjCiTHTKXr8](https://www.youtube.com/watch?v=NjCiTHTKXr8)

If the question was related to removing noise in the reconstruction, then adding Manual Tie Points (MTPs) as Selim recommended should help!

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**Author:** ![Moshe\_Mandelmilch](https://avatars.discourse-cdn.com/v4/letter/m/ac91a4/32.png) [@Moshe\_Mandelmilch](https://community.pix4d.com/u/Moshe_Mandelmilch)\
**Post date:** [August 22, 2018, 6:14am UTC](https://community.pix4d.com/t/dtm-for-mapping/5924/4 "2018-08-22T06:14:34Z")

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Hello Admin,

I am using the Phantom 4 RGB camera in order to map some forest plots.&nbsp; My goal is to produce the ortho- mosaic of the plots and also a DSM of the plots. Regarding to the DSM, I would like to get the trees height&nbsp; in order to compare it to a validation information from the field. I&nbsp; notice that the DSM that i produced included the mean sea level, meaning that when&nbsp;I checked the&nbsp;height of a certain tree, this height was included the mean sea level. Is&nbsp; it possible to get the DSM of only the tree without the mean sea level? is it possible to get it in two different products?&nbsp;

&nbsp;

Thanks, Best regards,

Moshe

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**Author:** ![Cristina\_Timofte](https://sea2.discourse-cdn.com/pix4d/user_avatar/community.pix4d.com/cristina_timofte/32/221_2.png) [@Cristina\_Timofte](https://community.pix4d.com/u/Cristina_Timofte)\
**Post date:** [August 22, 2018, 3:35pm UTC](https://community.pix4d.com/t/dtm-for-mapping/5924/5 "2018-08-22T15:35:12Z")

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Hi Moshe,

&nbsp;

I believe you could&nbsp;extract the heights from the&nbsp;trees by subtracting the&nbsp;DTM from DSM in a third party software as QGIS.

&nbsp;

I hope this helps,

Ina