<p>They indicate wind direction (given by the long line or "barb") and speed (given by the shorter flags extending from each barb). In the same linked page you can read:</p>

<blockquote>
  <p>The barbs extending from each wind speed data point indicate the
  compass direction of the wind (e.g., a wind blowing from the north
  will have a barb straight up above the point; a wind blowing from the
  west will have a barb off to the left). Full and half flags extending
  from the barbs indicate the wind speed, with each half flag
  representing approximately 2.5 meters per second. A circle in place of
  a barb indicates a wind speed less than 2.5 meters per second.</p>
</blockquote>

CC BY-SA 4.0
2019-02-24T00:56:01.693Z
Thanks for the speedy answer! I am remiss for not noticing it was on the page already. I wonder if there is any utility to modulating the barb size on data points that *already indicate* the wind speed, or if it's done simply because it's standard. Also wondering if 2.5 m/s per half-barb is standard, or if these chars always need a half-barb scale explanation. Do you think those need a separate question?
uhoh
CC BY-SA 4.0
2019-02-24T01:05:23.347Z
Yes the flags are redundant in a speed plot, but as you say it is used because it is standard in meteorograms (barbs that include flags). The flags also make a bit more intuitive to figure out the direction the barb is pointing to.
The speed of 2.5 m/s per flag is not standard (at least not in the NOAA GFS meteorograms that I often use).
Camilo Rada
CC BY-SA 4.0
2019-08-28T21:06:14.987Z
the directional arrows and flags are a standard for most meteorological services around the world.
trond hansen
CC BY-SA 4.0
2019-02-24T00:52:11.150Z
2019-02-24T00:52:11.150Z
Camilo Rada
<p>According to <a href="https://space.stackexchange.com/a/34307/12102">this answer</a> the weather at the InSight lander on Mars can now be seen online at <a href="https://mars.nasa.gov/insight/weather/" rel="nofollow noreferrer">https://mars.nasa.gov/insight/weather/</a> This includes the wind speed and I believe the direction (if that's what those little flags mean).</p>

<p><strong>Question:</strong> But I'm not sure so I'd like to ask; what do the little flags on these martian wind speed data points mean?</p>

<p><a href="https://i.sstatic.net/fHZw5.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/fHZw5.png" alt="enter image description here"></a></p>

<hr>

<p>A bit of history...</p>

<p>From the question <a href="https://space.stackexchange.com/q/21680/12102">Was the telltale on the Mars Phoenix Lander used for meteorology? Why not a hot wire anemometer instead?</a></p>

<p><a href="https://i.sstatic.net/FJbPa.gif" rel="nofollow noreferrer"><img src="https://i.sstatic.net/FJbPa.gif" alt="enter image description here"></a></p>

<p><strong>above:</strong> GIF from images transmitted from Mars. From the <a href="http://marslab.au.dk/research/instrument-development/the-telltale-project/" rel="nofollow noreferrer">The Telltale project</a> page on the <a href="http://marslab.au.dk/" rel="nofollow noreferrer">Mars Simulation Laboratory</a>. Also <a href="https://web.archive.org/web/20120220080017/http://www.marslab.dk/TelltaleProject.html" rel="nofollow noreferrer">archived here</a>.</p>

CC BY-SA 4.0
2019-02-24T00:43:15.850Z
Related: [How does InSight measure wind speed?](https://space.stackexchange.com/q/34404/12102)
uhoh
CC BY-SA 4.0
2019-02-24T01:08:36.903Z
@gansub yep! https://mars.nasa.gov/resources/22199/of-wind-and-dust-devils-on-mars/?site=insight
uhoh
CC BY-SA 4.0
2019-02-24T01:36:00.367Z
@gansub one step at a time, let's see if there is data: [Does Mars have a known “prevailing wind” direction?](https://space.stackexchange.com/q/34412/12102)
uhoh
CC BY-SA 4.0
2019-02-24T01:56:20.260Z
@gansub The 750 GeV "blip" at CERN [generated 500 scholarly papers with theoretical explanations](https://cosmosmagazine.com/physics/tantalising-lhc-blip-not-a-particle-after-all) before it was found that it didn't exist. Start with data.
uhoh
CC BY-SA 4.0
2019-02-24T22:02:43.950Z
@gansub https://space.stackexchange.com/a/34424/12102
uhoh
<meteorology><mars>
What do the little flags on these martian wind speed data points mean?
uhoh
# What do the little flags on these martian wind speed data points mean?

(Asked by: username_0 on 2019-02-24)

According to [this answer](https://space.stackexchange.com/a/34307/12102) the weather at the InSight lander on Mars can now be seen online at <https://mars.nasa.gov/insight/weather/> This includes the wind speed and I believe the direction (if that's what those little flags mean).

**Question:** But I'm not sure so I'd like to ask; what do the little flags on these martian wind speed data points mean?

[![enter image description here](https://i.sstatic.net/fHZw5.png)](https://i.sstatic.net/fHZw5.png)

---

A bit of history...

From the question [Was the telltale on the Mars Phoenix Lander used for meteorology? Why not a hot wire anemometer instead?](https://space.stackexchange.com/q/21680/12102)

[![enter image description here](https://i.sstatic.net/FJbPa.gif)](https://i.sstatic.net/FJbPa.gif)

**above:** GIF from images transmitted from Mars. From the [The Telltale project](http://marslab.au.dk/research/instrument-development/the-telltale-project/) page on the [Mars Simulation Laboratory](http://marslab.au.dk/). Also [archived here](https://web.archive.org/web/20120220080017/http://www.marslab.dk/TelltaleProject.html).

**Tags:** meteorology, mars

> **Comments:**
> **username_0**: Related: [How does InSight measure wind speed?](https://space.stackexchange.com/q/34404/12102)  
> **username_0**: @gansub yep! https://mars.nasa.gov/resources/22199/of-wind-and-dust-devils-on-mars/?site=insight  
> **username_0**: @gansub one step at a time, let's see if there is data: [Does Mars have a known “prevailing wind” direction?](https://space.stackexchange.com/q/34412/12102)  
> **username_0**: @gansub The 750 GeV "blip" at CERN [generated 500 scholarly papers with theoretical explanations](https://cosmosmagazine.com/physics/tantalising-lhc-blip-not-a-particle-after-all) before it was found that it didn't exist. Start with data.  
> **username_0**: @gansub https://space.stackexchange.com/a/34424/12102  

---

## 1 answers

### Answer by username_1 on 2019-02-24. Score: 5 | Accepted answer

They indicate wind direction (given by the long line or "barb") and speed (given by the shorter flags extending from each barb). In the same linked page you can read:

> The barbs extending from each wind speed data point indicate the
> compass direction of the wind (e.g., a wind blowing from the north
> will have a barb straight up above the point; a wind blowing from the
> west will have a barb off to the left). Full and half flags extending
> from the barbs indicate the wind speed, with each half flag
> representing approximately 2.5 meters per second. A circle in place of
> a barb indicates a wind speed less than 2.5 meters per second.

> **Comments:**
> **username_0**: Thanks for the speedy answer! I am remiss for not noticing it was on the page already. I wonder if there is any utility to modulating the barb size on data points that *already indicate* the wind speed, or if it's done simply because it's standard. Also wondering if 2.5 m/s per half-barb is standard, or if these chars always need a half-barb scale explanation. Do you think those need a separate question?  
> **username_1**: Yes the flags are redundant in a speed plot, but as you say it is used because it is standard in meteorograms (barbs that include flags). The flags also make a bit more intuitive to figure out the direction the barb is pointing to. The speed of 2.5 m/s per flag is not standard (at least not in the NOAA GFS meteorograms that I often use).  
> **username_2**: the directional arrows and flags are a standard for most meteorological services around the world.  

---

