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Can I make a visibility analysis with mask for non visible areas?

Breakline detection algorithms for LiDAR dataset?Building extraction with LiDAR data (Improve Process)Floor height creation from Aerial Lidar/Imagery onlyMake a ground mask raster with the Greater Than toolSite viewshed with DSM: removing “false” visibility readings from trees and buildingsArcScene can't symbolize LAS points by classification code or return numberCalculate visibility with polygonal visual barriersAdd building height as obstructions to viewshed analysis in ArcGIS Desktop?Is it possible to do a visibility analysis and create a 3d - cone as a result in ArcGIS?Viewshed Analysis for Custom DEM file

0

I have LIDAR data and I've made a digital elevation model (with all the vàlues).

I've made a visibility analysis for 3 buildings with this model:

But as you can see in the orthophoto, there are a few forest areas where the trees block the view of the buildings from the ground level and yet, they appear as visible (from the top of the trees I guess). The same happens with the roof of another Building:

So my question is: Is there any way to use a layer (vector or raster) as a mask for non-visible àreas when you run a visibility analysis?

I'm currently working with ArcMap 10.3 but I'm open to suggestions with QGIS 3

dem lidar viewshed masking visibility

share|improve this question

edited 2 hours ago

Vince

14.6k32748

asked 2 days ago

Francesc Cañas SolerFrancesc Cañas Soler

66

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I've thought to isolate the buildings and vegetation and make a raster with all the others values as non-data and make a difference with visibility, but it is not accurate either because behind the buildings or vegetation remain as visible and it's not true.
  
  – Francesc Cañas Soler
  2 days ago
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  I would be happy to vote to reopen if you update your post with pictures, drawings, screenshots or some other way to clarify what you're asking.
  
  – csk
  yesterday
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I hope now is more clear, thanks
  
  – Francesc Cañas Soler
  8 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Where is exactly the observer in last 2 pictures? What I don't understand is that you are running a visibility analysis and pre defining which areas should appear and which should not. If top of trees are visible from the ground where the buildings are located, why shouldn't they appear in the visibility analysis? If there was a way to mask, which mask would you use? Wouldn't the mask (which would represent visible areas) already be the result you are trying to achieve? Also, you mention you use a DEM (bare-earth), but did you mean a DSM (elevation with above ground objects)?
  
  – Andre Silva
  53 mins ago
  

  
  
  
  

add a comment | 

0

I have LIDAR data and I've made a digital elevation model (with all the vàlues).

I've made a visibility analysis for 3 buildings with this model:

But as you can see in the orthophoto, there are a few forest areas where the trees block the view of the buildings from the ground level and yet, they appear as visible (from the top of the trees I guess). The same happens with the roof of another Building:

So my question is: Is there any way to use a layer (vector or raster) as a mask for non-visible àreas when you run a visibility analysis?

I'm currently working with ArcMap 10.3 but I'm open to suggestions with QGIS 3

dem lidar viewshed masking visibility

share|improve this question

edited 2 hours ago

Vince

14.6k32748

asked 2 days ago

Francesc Cañas SolerFrancesc Cañas Soler

66

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I've thought to isolate the buildings and vegetation and make a raster with all the others values as non-data and make a difference with visibility, but it is not accurate either because behind the buildings or vegetation remain as visible and it's not true.
  
  – Francesc Cañas Soler
  2 days ago
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  I would be happy to vote to reopen if you update your post with pictures, drawings, screenshots or some other way to clarify what you're asking.
  
  – csk
  yesterday
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I hope now is more clear, thanks
  
  – Francesc Cañas Soler
  8 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Where is exactly the observer in last 2 pictures? What I don't understand is that you are running a visibility analysis and pre defining which areas should appear and which should not. If top of trees are visible from the ground where the buildings are located, why shouldn't they appear in the visibility analysis? If there was a way to mask, which mask would you use? Wouldn't the mask (which would represent visible areas) already be the result you are trying to achieve? Also, you mention you use a DEM (bare-earth), but did you mean a DSM (elevation with above ground objects)?
  
  – Andre Silva
  53 mins ago
  

  
  
  
  

add a comment | 

I have LIDAR data and I've made a digital elevation model (with all the vàlues).

I've made a visibility analysis for 3 buildings with this model:

But as you can see in the orthophoto, there are a few forest areas where the trees block the view of the buildings from the ground level and yet, they appear as visible (from the top of the trees I guess). The same happens with the roof of another Building:

So my question is: Is there any way to use a layer (vector or raster) as a mask for non-visible àreas when you run a visibility analysis?

I'm currently working with ArcMap 10.3 but I'm open to suggestions with QGIS 3

dem lidar viewshed masking visibility

share|improve this question

edited 2 hours ago

Vince

14.6k32748

asked 2 days ago

Francesc Cañas SolerFrancesc Cañas Soler

66

share|improve this question

edited 2 hours ago

Vince

14.6k32748

asked 2 days ago

Francesc Cañas SolerFrancesc Cañas Soler

66

share|improve this question

edited 2 hours ago

Vince

14.6k32748

asked 2 days ago

Francesc Cañas SolerFrancesc Cañas Soler

66

edited 2 hours ago

Vince

14.6k32748

edited 2 hours ago

Vince

14.6k32748

asked 2 days ago

Francesc Cañas SolerFrancesc Cañas Soler

66

asked 2 days ago

Francesc Cañas SolerFrancesc Cañas Soler

66

1 Answer
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0

with a dsm, observer will be considered on the surface (top of trees), which is indeed unrealistic. My suggested workaround is to only keep the boundaries of your forest and set the ground level in the middle. You can do this by, e.g.,

1. computing DSM - DEM (which gives you the Digital height model)


2. using focal stat to compute the local minimum of your DHM (in a 3by
   3 window)


3. computing DSM- local min of DHM

share|improve this answer

answered 2 days ago

radouxjuradouxju

40.7k143119

add a comment | 

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0

with a dsm, observer will be considered on the surface (top of trees), which is indeed unrealistic. My suggested workaround is to only keep the boundaries of your forest and set the ground level in the middle. You can do this by, e.g.,

1. computing DSM - DEM (which gives you the Digital height model)


2. using focal stat to compute the local minimum of your DHM (in a 3by
   3 window)


3. computing DSM- local min of DHM

share|improve this answer

answered 2 days ago

radouxjuradouxju

40.7k143119

add a comment | 

0

with a dsm, observer will be considered on the surface (top of trees), which is indeed unrealistic. My suggested workaround is to only keep the boundaries of your forest and set the ground level in the middle. You can do this by, e.g.,

1. computing DSM - DEM (which gives you the Digital height model)


2. using focal stat to compute the local minimum of your DHM (in a 3by
   3 window)


3. computing DSM- local min of DHM

share|improve this answer

answered 2 days ago

radouxjuradouxju

40.7k143119

add a comment | 

with a dsm, observer will be considered on the surface (top of trees), which is indeed unrealistic. My suggested workaround is to only keep the boundaries of your forest and set the ground level in the middle. You can do this by, e.g.,

1. computing DSM - DEM (which gives you the Digital height model)


2. using focal stat to compute the local minimum of your DHM (in a 3by
   3 window)


3. computing DSM- local min of DHM

share|improve this answer

answered 2 days ago

radouxjuradouxju

40.7k143119

share|improve this answer

answered 2 days ago

radouxjuradouxju

40.7k143119

answered 2 days ago

radouxjuradouxju

40.7k143119

answered 2 days ago

radouxjuradouxju

40.7k143119