<p>Just taking a guess from the context, I think it could be a "view shed", the term used in GIS (Geographic Information Systems) to refer to a visibility analysis. In other words, it is a calculation that determines which areas of a given terrain would be visible from a specific point.</p>

<p>It is used to know, for example, what would be the coverage of a radio transmitter on a given location, or from which areas would a lighthouse not be visible, etc. To calculate such diagram you need a DEM (Digital Elevation Model) of the area.</p>

<p>To give you an example I just loaded a DEM and run a calculation (using Global Mapper) of the areas visible from a 20 meters tall tower in the top of a specific hill, and within a 40 km radius. And this is how the results looks like:
<a href="https://i.sstatic.net/k58LV.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/k58LV.png" alt="enter image description here"></a></p>

<p>Where the red shading show the areas that are visible from the tower. The rest of the terrain would be hidden behind topographic obstacles.</p>

CC BY-SA 3.0
2018-03-29T17:13:44.417Z
2018-03-29T17:13:44.417Z
Camilo Rada
<p>Currently I do some research about SODAR and at <a href="https://ac.els-cdn.com/S1352231097003853/1-s2.0-S1352231097003853-main.pdf?_tid=982ada2c-a959-4c4d-af9c-1e5de179c7da&amp;acdnat=1522340401_61816cf131c03b50bbfc47eb9ab31617" rel="nofollow noreferrer">this paper</a>, the author wrote (p. 1502f):</p>

<blockquote>
  <p>A site should be relatively clear of obstacles that could act as
  potential fixed-echo reflectors. If that is not possible, then it is
  therefore important to construct an <strong>obstacle vista diagram</strong> prior to
  sodar installation  which  identifies  the  direction  and  height 
  of potential reflectors in relation to the sodar (Baxter, 1994, 1996).
  This diagram can be used after some data have been collected to assess
  whether or not reflections are of concern at some sodar height ranges.</p>
</blockquote>

<p>Unfortunately, I can't find any access to the referenced literature and google wasn't helpful either. So, what is an obstacle vista diagram and how to construct it?</p>

<meteorology><wind><remote-sensing>
What is an 'obstacle vista diagram'?
sequoia
# What is an 'obstacle vista diagram'?

(Asked by: username_0 on 2018-03-29)

Currently I do some research about SODAR and at [this paper](https://ac.els-cdn.com/S1352231097003853/1-s2.0-S1352231097003853-main.pdf?_tid=982ada2c-a959-4c4d-af9c-1e5de179c7da&acdnat=1522340401_61816cf131c03b50bbfc47eb9ab31617), the author wrote (p. 1502f):

> A site should be relatively clear of obstacles that could act as
> potential fixed-echo reflectors. If that is not possible, then it is
> therefore important to construct an **obstacle vista diagram** prior to
> sodar installation which identifies the direction and height
> of potential reflectors in relation to the sodar (Baxter, 1994, 1996).
> This diagram can be used after some data have been collected to assess
> whether or not reflections are of concern at some sodar height ranges.

Unfortunately, I can't find any access to the referenced literature and google wasn't helpful either. So, what is an obstacle vista diagram and how to construct it?

**Tags:** meteorology, wind, remote-sensing


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## 1 answers

### Answer by username_1 on 2018-03-29. Score: 3 | Accepted answer

Just taking a guess from the context, I think it could be a "view shed", the term used in GIS (Geographic Information Systems) to refer to a visibility analysis. In other words, it is a calculation that determines which areas of a given terrain would be visible from a specific point.

It is used to know, for example, what would be the coverage of a radio transmitter on a given location, or from which areas would a lighthouse not be visible, etc. To calculate such diagram you need a DEM (Digital Elevation Model) of the area.

To give you an example I just loaded a DEM and run a calculation (using Global Mapper) of the areas visible from a 20 meters tall tower in the top of a specific hill, and within a 40 km radius. And this is how the results looks like:
[![enter image description here](https://i.sstatic.net/k58LV.png)](https://i.sstatic.net/k58LV.png)

Where the red shading show the areas that are visible from the tower. The rest of the terrain would be hidden behind topographic obstacles.


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