Litichi above ground ?

[dirtfishingman]

Can some one shed some light on this for me. Whats the deal with this setting see the photo. What does it do

 

[zeusfl]

When you do not check the box for example and you set 100 ft, the drone will fly always 100 ft from the take off position. When you select the box will be always 100ft above the ground even if is a 200ft mountain at front. With the check box selected the drone will never crash the mountain (in theory). Without the box will crash since the mountain is higher than the take off position + 100 ft

 

[dirtfishingman]

When you do not check the box for example and you set 100 ft, the drone will fly always 100 ft from the take off position. When you select the box will be always 100ft above the ground even if is a 200ft mountain at front. With the check box selected the drone will never crash the mountain (in theory). Without the box will crash.

Thank u have u tried it?

 

[zeusfl]

Thank u have u tried it?

Yes it works. Litchi needs the googles maps altitude reference. Is better load the map with anticipation to make it work if you do not have internet connectivity.

 

[Skybuyer]

When you do not check the box for example and you set 100 ft, the drone will fly always 100 ft from the take off position. When you select the box will be always 100ft above the ground even if is a 200ft mountain at front. With the check box selected the drone will never crash the mountain (in theory). Without the box will crash since the mountain is higher than the take off position + 100 ft

That is correct. But let me say the same thing a different way for clarity...

When you don't check the box it's like telling Litchi "all the land I'm flying over is the same elevation". If the ground you're over is flat or hilly, or a mountain range, regardless, your drone will fly at that steady 100 ft above whatever that elevation is 100 feet above your launch point without adjustment for dips or rises in the terrain. But let's say that you check the "above current level" box and the ground rises 5 ft, your drone will adjust to 105 ft, but stay at 100ft AGL (above ground level) from below that very spot. To take zeusfl's mountain ancedote, if you're flying into a mountain and you have the "above current level" box checked, theoretically as you fly toward the mountain your drone will continue to ascend to keep it 100 feet above whatever the current level you're over at that moment.

It's kind of a miracle of modern technology. Litchi, in the settings has a feature/preference/checkbox, "Use Online Elevation". It uses Google Earth (I believe) to know what the elevation is of every inch of terrain we fly over. If that box isn't checked in preference you will not be able to √ the "above current level" box to use that feature/function.

 

[Skybuyer]

One more thing... Do you know you can set up your missions at home on your computer and "proof" them in a virtual mission flight on your computer? I did one today and the virtual mission told me what adjustments I needed to make, so all I have to do when flying is hit "start" and keep an eye on my drone to make sure it does what it is supposed to do... and not crash into anything.

 

[zeusfl]

One more thing... Do you know you can set up your missions at home on your computer and "proof" them in a virtual mission flight on your computer? I did one today and the virtual mission told me what adjustments I needed to make, so all I have to do when flying is hit "start" and keep an eye on my drone to make sure it does what it is supposed to do... and not crash into anything.

You can export the KML file to Google Earth and see all the elevation from the mission to make sure everything is ok.

 

[Dave Maine]

Also remember that if you plan a remote mission using the height above takeoff option, that you must take off when you fly the mission from the same takeoff point. If you don’t the drone’s height above ground will be offset by the difference between the takeoff point used in planning the mission, and the takeoff point used when taking off to actually fly the mission.

 

[Pappy]

Do you know you can set up your missions at home on your computer and "proof" them in a virtual mission flight on your computer?

I live in a mountainous area and so "Above Ground" is always checked and I always check the "Mission" by exporting and viewing it in 3d from Google Earth. When I did this for one mission the line of flight was going through a mountain ridge instead of over it. So that saved me from a failed mission and all I had to do was to add a waypoint to the top of the ridge. Can't say enough about the Litchi's MIssion Hub web page, makes waypoint missions easy to setup and share with others.

 

[Skybuyer]

You can export the KML file to Google Earth and see all the elevation from the mission to make sure everything is ok.

Yes. That too. I discovered KML early on. What I found out later is that you can download the app Virtual Litchi Mission (VLM) and in conjunction with the Litchi Mission Hub and Google earth you can export VLM files which will allow you to fly the mission virtually.
Here is the link for Virtual Litchi Mission: Virtual Litchi Mission Download
And here is the link to the forum member who posted this: namirda thread with Litchi link and information

Edit: I just found this link to a video detailing VLM. I have to watch this fully myself but wanted to get it posted before I forget. What I saw in the first minute or so of the video is that I didn't realize you could set up the mission in Google Earth (?).

There is one downside to Litchi. It can make you lazy about manual flying. I'm planning some missions that I don't know that I'd have the skill and patience to fly manually, which I think may slow down my skill development. It's so much easier to push the start button than hold the sticks down continuously, though I think more precision can be had flying manually.

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies

 

[Jeff A]

When you do not check the box for example and you set 100 ft, the drone will fly always 100 ft from the take off position. When you select the box will be always 100ft above the ground even if is a 200ft mountain at front. With the check box selected the drone will never crash the mountain (in theory). Without the box will crash since the mountain is higher than the take off position + 100 ft

I'm sorry, but I can't agree fully with your statement, With the above ground box checked, and you have stated that you should be 100 feet above the elevation of the Waypoint, you should be. If, on the way to that Waypoint there is a hill that is higher than where your Waypoint is, lets say 150 feet higher, you will most likely hit that hill. Litchi only assures (Maybe) that you will cross the Waypoint at the listed altitude. You have to be very careful in the placement of your Waypoints and you have to be even more careful of what is between those Waypoints including terrain, trees and power lines to name a few. After careful flight planning, fly a Virtual Litchi mission and try it out. Oh, the Virtual trees are never as tall as the actual trees.

 

[Skybuyer]

I live in a mountainous area and so "Above Ground" is always checked and I always check the "Mission" by exporting and viewing it in 3d from Google Earth. When I did this for one mission the line of flight was going through a mountain ridge instead of over it. So that saved me from a failed mission and all I had to do was to add a waypoint to the top of the ridge. Can't say enough about the Litchi's MIssion Hub web page, makes waypoint missions easy to setup and share with others.

You know what would be cool? To have a section where we can share the missions so that others can fly your mission virtually and see what you're seeing. Here, in the flatlands of Cook County Illinois the only elevation varations are the buildings. The only thing that is interesting to fly is the Lake Michigan shore, but one has to tread carefully because the law here is whatever the authority on scene says it is and the local ordinance has a confiscation clause in it, and because of the way things work, while the state has claimed sole jurisdiction over flying regulation they have created a carve-out in the law to exclude Chicago.

 

[Skybuyer]

I'm sorry, but I can't agree fully with your statement, With the above ground box checked, and you have stated that you should be 100 feet above the elevation of the Waypoint, you should be. If, on the way to that Waypoint there is a hill that is higher than where your Waypoint is, lets say 150 feet higher, you will most likely hit that hill. Litchi only assures (Maybe) that you will cross the Waypoint at the listed altitude. You have to be very careful in the placement of your Waypoints and you have to be even more careful of what is between those Waypoints including terrain, trees and power lines to name a few. After careful flight planning, fly a Virtual Litchi mission and try it out. Oh, the Virtual trees are never as tall as the actual trees.

Thanks. It hadn't occurred to me that Litchi wouldn't adapt foot by foot, but only have a transition of elevations between waypoints. It only makes sense because it wouldn't take into consideration structures that might get in the way. Thanks for the clarification. I'm sure it will come in handy at some point. FWIW, the sensors in my M2 saved me once as the RTH after a mission was miscalculated by about 40 feet based on the published height of a structure. It made for a very cool shot, but totally unintended. I was surprised (and relieved) when and after I saw the footage. Warning to Mini owners: Mini's don't have the luxury of obstacle avoidance sensors, so be very careful when planning- especially on RTH.

 

[dirtfishingman]

That is correct. But let me say the same thing a different way for clarity...

When you don't check the box it's like telling Litchi "all the land I'm flying over is the same elevation". If the ground you're over is flat or hilly, or a mountain range, regardless, your drone will fly at that steady 100 ft above whatever that elevation is 100 feet above your launch point without adjustment for dips or rises in the terrain. But let's say that you check the "above current level" box and the ground rises 5 ft, your drone will adjust to 105 ft, but stay at 100ft AGL (above ground level) from below that very spot. To take zeusfl's mountain ancedote, if you're flying into a mountain and you have the "above current level" box checked, theoretically as you fly toward the mountain your drone will continue to ascend to keep it 100 feet above whatever the current level you're over at that moment.

It's kind of a miracle of modern technology. Litchi, in the settings has a feature/preference/checkbox, "Use Online Elevation". It uses Google Earth (I believe) to know what the elevation is of every inch of terrain we fly over. If that box isn't checked in preference you will not be able to √ the "above current level" box to use that feature/function.

awesome thanks.. next ? How accurate is Googles elevations

 

[dirtfishingman]

Thank u all

 

[Keule]

How accurate is Googles elevations

The accuracy of the elevation data can range from 5 to 10 meter, depending on where you are.

 

[Skybuyer]

awesome thanks.. next ? How accurate is Googles elevations

Scary good. Open Google Earth and find a location that you're familiar with a building. Hover over the ground and see what elevation (MSL) is shown on the lower right. Then hover over the top of a tall builidng and get that elevation. Because it's shown in MSL you'll have to do some math, but you'll find that you can calculate how tall structures are with Google Earth.

I recently had one "near miss" incident, saved by the obstacle sensors. I relied on the published information citing the building as being 138 feet tall. I thought I had done my due diligence. I was flying a Litchi mission and had it set to RTH and thought I had enough height set, not even considering that the drone would make a bee-line back and "home" was on the opposite side of the building, which I also should have considered and made a newbie mistake which I'll never make again. To my surprise when I got home I saw the near miss on film. I subsequently checked on Google Earth, only then I learned that the building wasn't 138' tall... but 178'!!!

 

[Pappy]

You know what would be cool? To have a section where we can share the missions so that others can fly your mission virtually and see what you're seeing.

You can pretty much does this already in the MIssion Hub. You can check out it out without an account at Mission Hub - Litchi . When you see the icon you can double click on it to view a video recording of the flight for the shared waypoint mission as well as the details for it. With the Litchi app on your phone you can then download and execute the shared mission. All shared missions have been created by the LItichi user base.

 

[Pappy]

How accurate is Googles elevations

For the USA the geological data is from the US government scientific agency - US Geological Survey, so it should be very accurate.