SeeYou incorrect waypoint altitudes

[soaringjac]

Just started using seeyou for the first time. I created some waypoints in seeyou and noticed the altitude shown for some of the waypoints are way off. I double checked the exact same point in Google earth and the difference is about 1000'. This isn't the case for all custom waypoints I made, but it is true for most of them. How are you guys creating accurate waypoints and waypoint altitudes. Kind of crazy that seeyou is so off!

[Paul Ruskin[_2_]]

At 03:59 01 February 2020, soaringjac wrote:
>Just started using seeyou for the first time. I created some
waypoints in
>s=
>eeyou and noticed the altitude shown for some of the waypoints are
way
>off.=
> I double checked the exact same point in Google earth and the
difference
>i=
>s about 1000'. This isn't the case for all custom waypoints I made,
but it
>=
>is true for most of them. How are you guys creating accurate
waypoints and
>=
>waypoint altitudes. Kind of crazy that seeyou is so off!
>

Are you getting confused between metres and feet? See you will work
in either and will convert between them.

Paul

[Paul Remde]

Hi,

I suspect that one of 2 things is happening.
- You may be using a bad turnpoint database. I recommend the data found here:
http://cumulus-soaring.com/seeyou.htm#Downloads
- If you are viewing a flight log, SeeYou can automatically use the take-off and landing elevations and the SeeYou ground elevation database to offset all the flight log points to account for barometric pressure changes. It is a very nice feature.

You may want to check-out my SeeYou Tips document.
http://cumulus-soaring.com/seeyou/SeeYou-Tips.pdf

Best Regards,

Paul Remde

On Friday, January 31, 2020 at 9:59:13 PM UTC-6, soaringjac wrote:
> Just started using seeyou for the first time. I created some waypoints in seeyou and noticed the altitude shown for some of the waypoints are way off. I double checked the exact same point in Google earth and the difference is about 1000'. This isn't the case for all custom waypoints I made, but it is true for most of them. How are you guys creating accurate waypoints and waypoint altitudes. Kind of crazy that seeyou is so off!

[soaringjac]

On Saturday, February 1, 2020 at 1:00:05 AM UTC-8, Paul Ruskin wrote:
> At 03:59 01 February 2020, soaringjac wrote:
> >Just started using seeyou for the first time. I created some
> waypoints in
> >s=
> >eeyou and noticed the altitude shown for some of the waypoints are
> way
> >off.=
> > I double checked the exact same point in Google earth and the
> difference
> >i=
> >s about 1000'. This isn't the case for all custom waypoints I made,
> but it
> >=
> >is true for most of them. How are you guys creating accurate
> waypoints and
> >=
> >waypoint altitudes. Kind of crazy that seeyou is so off!
> >
>
> Are you getting confused between metres and feet? See you will work
> in either and will convert between them.
>
> Paul

its definitely showing me feet

[soaringjac]

On Saturday, February 1, 2020 at 7:14:46 AM UTC-8, Paul Remde wrote:
> Hi,
>
> I suspect that one of 2 things is happening.
> - You may be using a bad turnpoint database. I recommend the data found here:
> http://cumulus-soaring.com/seeyou.htm#Downloads
> - If you are viewing a flight log, SeeYou can automatically use the take-off and landing elevations and the SeeYou ground elevation database to offset all the flight log points to account for barometric pressure changes. It is a very nice feature.
>
> You may want to check-out my SeeYou Tips document.
> http://cumulus-soaring.com/seeyou/SeeYou-Tips.pdf
>
> Best Regards,
>
> Paul Remde
>
> On Friday, January 31, 2020 at 9:59:13 PM UTC-6, soaringjac wrote:
> > Just started using seeyou for the first time. I created some waypoints in seeyou and noticed the altitude shown for some of the waypoints are way off. I double checked the exact same point in Google earth and the difference is about 1000'. This isn't the case for all custom waypoints I made, but it is true for most of them. How are you guys creating accurate waypoints and waypoint altitudes. Kind of crazy that seeyou is so off!

Thanks Paul! I am not using any turnpoint database and not viewing any flight log. I am just trying to mark some local landmarks as waypoints to put into my S100 vario. Im going to play around with it a bit more and see if i can figure out whats going on, but to me it seems like the see your elevations are not accurate. I guess i can always create the waypoints and then edit their altitudes based on the alt i get from google earth, which kind of sucks

[Eric Greenwell[_4_]]

soaringjac wrote on 1/31/2020 7:59 PM:
> Just started using seeyou for the first time. I created some waypoints in seeyou and noticed the altitude shown for some of the waypoints are way off. I double checked the exact same point in Google earth and the difference is about 1000'. This isn't the case for all custom waypoints I made, but it is true for most of them. How are you guys creating accurate waypoints and waypoint altitudes. Kind of crazy that seeyou is so off!
>
For what purpose will you use the waypoints? If it's for task planning, the
correct elevation doesn't matter; if it's for potential landing places, you should
not depend on SeeYou, but on a more accurate source. SeeYou is a flight planning
tool, and it's your flight computer that needs elevation accuracy. I use official
databases as my first choice; for landing places not in the official databases, I
use databases from pilots I trust, sometimes from Google, perhaps topographic
maps. I also plan to arrive higher at those landing places, partly because the
elevation may not be known as accurately as airports on the charts.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[Martin Gregorie[_6_]]

On Sat, 01 Feb 2020 07:38:03 -0800, soaringjac wrote:

> On Saturday, February 1, 2020 at 7:14:46 AM UTC-8, Paul Remde wrote:
>> Hi,
>>
>> I suspect that one of 2 things is happening.
>> - You may be using a bad turnpoint database. I recommend the data
>> found here:
>> http://cumulus-soaring.com/seeyou.htm#Downloads
>> - If you are viewing a flight log, SeeYou can automatically use the
>> take-off and landing elevations and the SeeYou ground elevation
>> database to offset all the flight log points to account for barometric
>> pressure changes. It is a very nice feature.
>>
>> You may want to check-out my SeeYou Tips document.
>> http://cumulus-soaring.com/seeyou/SeeYou-Tips.pdf
>>
>> Best Regards,
>>
>> Paul Remde
>>
>> On Friday, January 31, 2020 at 9:59:13 PM UTC-6, soaringjac wrote:
>> > Just started using seeyou for the first time. I created some
>> > waypoints in seeyou and noticed the altitude shown for some of the
>> > waypoints are way off. I double checked the exact same point in
>> > Google earth and the difference is about 1000'. This isn't the case
>> > for all custom waypoints I made, but it is true for most of them. How
>> > are you guys creating accurate waypoints and waypoint altitudes. Kind
>> > of crazy that seeyou is so off!
>
> Thanks Paul! I am not using any turnpoint database and not viewing any
> flight log. I am just trying to mark some local landmarks as waypoints
> to put into my S100 vario. Im going to play around with it a bit more
> and see if i can figure out whats going on, but to me it seems like the
> see your elevations are not accurate. I guess i can always create the
> waypoints and then edit their altitudes based on the alt i get from
> google earth, which kind of sucks

Post one of the problematic turnpoints here so we can see what might be
wrong. CUP files are just plaintext, so almost any program that can
display a text file can display it for cut'n pasting - even Word.


--
Martin | martin at
Gregorie | gregorie dot org

[Darryl Ramm]

On Friday, January 31, 2020 at 7:59:13 PM UTC-8, soaringjac wrote:
> Just started using seeyou for the first time. I created some waypoints in seeyou and noticed the altitude shown for some of the waypoints are way off. I double checked the exact same point in Google earth and the difference is about 1000'. This isn't the case for all custom waypoints I made, but it is true for most of them. How are you guys creating accurate waypoints and waypoint altitudes. Kind of crazy that seeyou is so off!

Describing exactly wha you are doing and providing sample data will help you get useful help.

Are you using SeeYou Windows app, SeeYou Mobile or SeeYou cloud?

How exactly are you creating a waypoint and how exactly are you looking at its elevation? If say you are looking at stuff in SeeYou Mobile then it may be you are getting confused with waypoint elevation, arrival height, etc.

Assuming you are using SeeYou Windows app as you move the cursor around you should see the elevation shown in the lower window border next to the cursor latitude and longitude, that changing display gives you an idea of the elevation data resolution. Elevation data is only useful within that resolution, if you are trying to pick super fine resolution elevation features it's not going to work. And pragmatically for anything important people usually hand-edit waypoint files, including elevation if needed.

If your SeeYou is not or has not been connected online I imagine it's possible that SeeYou has not downloaded the elevation data (I assume it's still downloading NASA elevation data, even that is a bit more hidden than it used to be).

[Tango Eight]

On Friday, January 31, 2020 at 10:59:13 PM UTC-5, soaringjac wrote:
> Just started using seeyou for the first time. I created some waypoints in seeyou and noticed the altitude shown for some of the waypoints are way off. I double checked the exact same point in Google earth and the difference is about 1000'. This isn't the case for all custom waypoints I made, but it is true for most of them. How are you guys creating accurate waypoints and waypoint altitudes. Kind of crazy that seeyou is so off!



I use https://viewer.nationalmap.gov/basic/ for accurate elevation data.

I used SeeYou 4 for a number of years and it worked pretty well in this regard. More recent versions... not so much. Ridge top waypoints created in SeeYou always have elevations lower than actual. I have seen errors as large as 600'.

Evan Ludeman / T8

[soaringjac]

On Saturday, February 1, 2020 at 7:48:36 AM UTC-8, Eric Greenwell wrote:
> soaringjac wrote on 1/31/2020 7:59 PM:
> > Just started using seeyou for the first time. I created some waypoints in seeyou and noticed the altitude shown for some of the waypoints are way off. I double checked the exact same point in Google earth and the difference is about 1000'. This isn't the case for all custom waypoints I made, but it is true for most of them. How are you guys creating accurate waypoints and waypoint altitudes. Kind of crazy that seeyou is so off!
> >
> For what purpose will you use the waypoints? If it's for task planning, the
> correct elevation doesn't matter; if it's for potential landing places, you should
> not depend on SeeYou, but on a more accurate source. SeeYou is a flight planning
> tool, and it's your flight computer that needs elevation accuracy. I use official
> databases as my first choice; for landing places not in the official databases, I
> use databases from pilots I trust, sometimes from Google, perhaps topographic
> maps. I also plan to arrive higher at those landing places, partly because the
> elevation may not be known as accurately as airports on the charts.
>
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Just adding a couple local landmarks to my S100, mainly going to use to see if I have glide to the various waypoints. Not doing any XC or competition stuff. I might try some databases but it seems a bit overkill for now. I just want a couple local landmarks.

[soaringjac]

On Saturday, February 1, 2020 at 11:48:39 AM UTC-8, Darryl Ramm wrote:
> On Friday, January 31, 2020 at 7:59:13 PM UTC-8, soaringjac wrote:
> > Just started using seeyou for the first time. I created some waypoints in seeyou and noticed the altitude shown for some of the waypoints are way off. I double checked the exact same point in Google earth and the difference is about 1000'. This isn't the case for all custom waypoints I made, but it is true for most of them. How are you guys creating accurate waypoints and waypoint altitudes. Kind of crazy that seeyou is so off!
>
> Describing exactly wha you are doing and providing sample data will help you get useful help.
>
> Are you using SeeYou Windows app, SeeYou Mobile or SeeYou cloud?
>
> How exactly are you creating a waypoint and how exactly are you looking at its elevation? If say you are looking at stuff in SeeYou Mobile then it may be you are getting confused with waypoint elevation, arrival height, etc..
>
> Assuming you are using SeeYou Windows app as you move the cursor around you should see the elevation shown in the lower window border next to the cursor latitude and longitude, that changing display gives you an idea of the elevation data resolution. Elevation data is only useful within that resolution, if you are trying to pick super fine resolution elevation features it's not going to work. And pragmatically for anything important people usually hand-edit waypoint files, including elevation if needed.
>
> If your SeeYou is not or has not been connected online I imagine it's possible that SeeYou has not downloaded the elevation data (I assume it's still downloading NASA elevation data, even that is a bit more hidden than it used to be).

I am using SeeYou windows app to create waypoints. I scroll and zoom around the map to find the place i want to mark, then i right click and select "waypoint here". Right clicking brings up a window with the elevation data in it. I do see the elevation data shown in the bottom left as well like you mention

[soaringjac]

On Saturday, February 1, 2020 at 9:43:59 AM UTC-8, Martin Gregorie wrote:
> On Sat, 01 Feb 2020 07:38:03 -0800, soaringjac wrote:
>
> > On Saturday, February 1, 2020 at 7:14:46 AM UTC-8, Paul Remde wrote:
> >> Hi,
> >>
> >> I suspect that one of 2 things is happening.
> >> - You may be using a bad turnpoint database. I recommend the data
> >> found here:
> >> http://cumulus-soaring.com/seeyou.htm#Downloads
> >> - If you are viewing a flight log, SeeYou can automatically use the
> >> take-off and landing elevations and the SeeYou ground elevation
> >> database to offset all the flight log points to account for barometric
> >> pressure changes. It is a very nice feature.
> >>
> >> You may want to check-out my SeeYou Tips document.
> >> http://cumulus-soaring.com/seeyou/SeeYou-Tips.pdf
> >>
> >> Best Regards,
> >>
> >> Paul Remde
> >>
> >> On Friday, January 31, 2020 at 9:59:13 PM UTC-6, soaringjac wrote:
> >> > Just started using seeyou for the first time. I created some
> >> > waypoints in seeyou and noticed the altitude shown for some of the
> >> > waypoints are way off. I double checked the exact same point in
> >> > Google earth and the difference is about 1000'. This isn't the case
> >> > for all custom waypoints I made, but it is true for most of them. How
> >> > are you guys creating accurate waypoints and waypoint altitudes. Kind
> >> > of crazy that seeyou is so off!
> >
> > Thanks Paul! I am not using any turnpoint database and not viewing any
> > flight log. I am just trying to mark some local landmarks as waypoints
> > to put into my S100 vario. Im going to play around with it a bit more
> > and see if i can figure out whats going on, but to me it seems like the
> > see your elevations are not accurate. I guess i can always create the
> > waypoints and then edit their altitudes based on the alt i get from
> > google earth, which kind of sucks
>
> Post one of the problematic turnpoints here so we can see what might be
> wrong. CUP files are just plaintext, so almost any program that can
> display a text file can display it for cut'n pasting - even Word.
>
>
> --
> Martin | martin at
> Gregorie | gregorie dot org

All you need to do to replicate is to make a waypoint in seeyou and note the elevation, then go to google earth or something similar and get the elevation for the same location. Most likely it is pretty different. In a couple cases for me its almost 1000' difference

[soaringjac]

On Sunday, February 2, 2020 at 7:41:03 AM UTC-8, Tango Eight wrote:
> On Friday, January 31, 2020 at 10:59:13 PM UTC-5, soaringjac wrote:
> > Just started using seeyou for the first time. I created some waypoints in seeyou and noticed the altitude shown for some of the waypoints are way off. I double checked the exact same point in Google earth and the difference is about 1000'. This isn't the case for all custom waypoints I made, but it is true for most of them. How are you guys creating accurate waypoints and waypoint altitudes. Kind of crazy that seeyou is so off!
>
>
>
> I use https://viewer.nationalmap.gov/basic/ for accurate elevation data.
>
> I used SeeYou 4 for a number of years and it worked pretty well in this regard. More recent versions... not so much. Ridge top waypoints created in SeeYou always have elevations lower than actual. I have seen errors as large as 600'.
>
> Evan Ludeman / T8

Thanks for the link T8!

[Eric Greenwell[_4_]]

soaringjac wrote on 2/2/2020 8:33 AM:
> On Saturday, February 1, 2020 at 7:48:36 AM UTC-8, Eric Greenwell wrote:
>> soaringjac wrote on 1/31/2020 7:59 PM:
>>> Just started using seeyou for the first time. I created some waypoints in seeyou and noticed the altitude shown for some of the waypoints are way off. I double checked the exact same point in Google earth and the difference is about 1000'. This isn't the case for all custom waypoints I made, but it is true for most of them. How are you guys creating accurate waypoints and waypoint altitudes. Kind of crazy that seeyou is so off!
>>>
>> For what purpose will you use the waypoints? If it's for task planning, the
>> correct elevation doesn't matter; if it's for potential landing places, you should
>> not depend on SeeYou, but on a more accurate source. SeeYou is a flight planning
>> tool, and it's your flight computer that needs elevation accuracy. I use official
>> databases as my first choice; for landing places not in the official databases, I
>> use databases from pilots I trust, sometimes from Google, perhaps topographic
>> maps. I also plan to arrive higher at those landing places, partly because the
>> elevation may not be known as accurately as airports on the charts.
>>
>
> Just adding a couple local landmarks to my S100, mainly going to use to see if I have glide to the various waypoints. Not doing any XC or competition stuff. I might try some databases but it seems a bit overkill for now. I just want a couple local landmarks.

I maybe be assuming the wrong things. What are you using as your flight computer,
and does it already have the local airports in it?

Usually, we use "landmark" for point of reference only, like a mountain peak or
bridge. By "landmarks", do you mean "places I could land safely?

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[Darryl Ramm]

Post the actual waypoint data here... it’s just ASCII text. Then we have a chance of seeing what is going on.

[Darryl Ramm]

This is *not* what happens for typical users. If it did everybody would be screaming. So no us just going and trying is not going to help you because it works fine except as noted near fine resolution peaks etc. So again, just post the waypoints you are seeing errors for.

[Tango Eight]

On Sunday, February 2, 2020 at 4:12:02 PM UTC-5, Darryl Ramm wrote:
> Post the actual waypoint data here... it’s just ASCII text. Then we have a chance of seeing what is going on.

Here you go. I created this waypoint about 3 minutes ago. Use whatever tool you like to correlate lat/long/elevation. Actual elevation closer to 1220m....

"Brumley Mountain",,,3650.274N,08206.228W,1091.5m,1,,,,,,

T8

[Martin Gregorie[_6_]]

On Sun, 02 Feb 2020 14:26:54 -0800, Tango Eight wrote:

> On Sunday, February 2, 2020 at 4:12:02 PM UTC-5, Darryl Ramm wrote:
>> Post the actual waypoint data here... it’s just ASCII text. Then we
>> have a chance of seeing what is going on.
>
> Here you go. I created this waypoint about 3 minutes ago. Use whatever
> tool you like to correlate lat/long/elevation. Actual elevation closer
> to 1220m....
>
> "Brumley Mountain",,,3650.274N,08206.228W,1091.5m,1,,,,,,
>
Interesting, so I went looking with Google Earth...

That point seems to be on the side of a forested ridge at 1187m on the
Blue Mountains in VA.

A more obvious TP would be the rock outcrops at 35 50.11.9N 82 06.1492W,
or 3550.119N 08206.119W in Seeyou format, but of course ymmv.

Of course, this all assumes the OP didn't mean "Bromley Mountain", at the
top of the Bromley Ski Resort, Vermont at 996m (43 13'15.67"N 072
56'19.37W or 4313.157N 07256.1837W in SeeYou format) - which would be a
much more obvious turnpoint.


--
Martin | martin at
Gregorie | gregorie dot org

[Tango Eight]

On Sunday, February 2, 2020 at 7:28:38 PM UTC-5, Martin Gregorie wrote:
> On Sun, 02 Feb 2020 14:26:54 -0800, Tango Eight wrote:
>
> > On Sunday, February 2, 2020 at 4:12:02 PM UTC-5, Darryl Ramm wrote:
> >> Post the actual waypoint data here... it’s just ASCII text. Then we
> >> have a chance of seeing what is going on.
> >
> > Here you go. I created this waypoint about 3 minutes ago. Use whatever
> > tool you like to correlate lat/long/elevation. Actual elevation closer
> > to 1220m....
> >
> > "Brumley Mountain",,,3650.274N,08206.228W,1091.5m,1,,,,,,
> >
> Interesting, so I went looking with Google Earth...
>
> That point seems to be on the side of a forested ridge at 1187m on the
> Blue Mountains in VA.
>
> A more obvious TP would be the rock outcrops at 35 50.11.9N 82 06.1492W,
> or 3550.119N 08206.119W in Seeyou format, but of course ymmv.
>
> Of course, this all assumes the OP didn't mean "Bromley Mountain", at the
> top of the Bromley Ski Resort, Vermont at 996m (43 13'15.67"N 072
> 56'19.37W or 4313.157N 07256.1837W in SeeYou format) - which would be a
> much more obvious turnpoint.
>
>
> --
> Martin | martin at
> Gregorie | gregorie dot org

It's a ridge route. If you've done any flying of that sort, it'll make sense. If you haven't... look at the the topo and do the thought experiment.

https://viewer.nationalmap.gov/basic/?basemap=b1&category=nbd,ned,nedsrc,histtopo,nhd,naip,nbdmi,gn is,smallscale,nsd,vectorcmb,ntd,ustopo,woodland&q=&zoom=12&bbox=-82.25360870,36.76584198,-81.94805145,36.91201927&preview=&avail=&refpoly=

T8

[soaringjac]

On Sunday, February 2, 2020 at 1:12:02 PM UTC-8, Darryl Ramm wrote:
> Post the actual waypoint data here... it’s just ASCII text. Then we have a chance of seeing what is going on.

Here is the waypoint
"Baden-Powell",Badenell,,3421.517N,11745.883W,2631.6m,1,,,,,,,

actual altitude is about 2865 meters

There is nothing specific about this waypoint, so it really does not matter.. Just click around the map in SeeYou and add some random waypoints and then compare to google earth altitudes

[[email protected]]

On Sunday, February 2, 2020 at 5:26:56 PM UTC-5, Tango Eight wrote:
> On Sunday, February 2, 2020 at 4:12:02 PM UTC-5, Darryl Ramm wrote:
> > Post the actual waypoint data here... it’s just ASCII text. Then we have a chance of seeing what is going on.
>
> Here you go. I created this waypoint about 3 minutes ago. Use whatever tool you like to correlate lat/long/elevation. Actual elevation closer to 1220m....
>
> "Brumley Mountain",,,3650.274N,08206.228W,1091.5m,1,,,,,,
>
> T8

The elevation data built into the map that is within SeeYou is only approximate, as it is presumably based on a "grid elevation model" with limited resolution. The more varied (mountaneous) the local topography, the more inaccurate it would be, since those grid points are farther apart than the actual local slopes. I always enter waypoint elevations "manually", from other sources.

[soaringjac]

On Sunday, February 2, 2020 at 5:35:27 PM UTC-8, wrote:
> On Sunday, February 2, 2020 at 5:26:56 PM UTC-5, Tango Eight wrote:
> > On Sunday, February 2, 2020 at 4:12:02 PM UTC-5, Darryl Ramm wrote:
> > > Post the actual waypoint data here... it’s just ASCII text. Then we have a chance of seeing what is going on.
> >
> > Here you go. I created this waypoint about 3 minutes ago. Use whatever tool you like to correlate lat/long/elevation. Actual elevation closer to 1220m....
> >
> > "Brumley Mountain",,,3650.274N,08206.228W,1091.5m,1,,,,,,
> >
> > T8
>
> The elevation data built into the map that is within SeeYou is only approximate, as it is presumably based on a "grid elevation model" with limited resolution. The more varied (mountaneous) the local topography, the more inaccurate it would be, since those grid points are farther apart than the actual local slopes. I always enter waypoint elevations "manually", from other sources.



Cool thanks, that's basically the answer i thought i would get. Pretty much "enter your elevations manually"

[Darryl Ramm]

On Sunday, February 2, 2020 at 2:26:56 PM UTC-8, Tango Eight wrote:
> On Sunday, February 2, 2020 at 4:12:02 PM UTC-5, Darryl Ramm wrote:
> > Post the actual waypoint data here... it’s just ASCII text. Then we have a chance of seeing what is going on.
>
> Here you go. I created this waypoint about 3 minutes ago. Use whatever tool you like to correlate lat/long/elevation. Actual elevation closer to 1220m....
>
> "Brumley Mountain",,,3650.274N,08206.228W,1091.5m,1,,,,,,
>
> T8

Hi Evan. I was not really asking you for a waypoint. We already discussed this, I hope we both understand why mountainous terrain elevations are likely to not be accurate/disagree like this. I was asking the OP for the waypoints *he* is having problems with. (I see we have a waypoint now, I'll look at that next).

If they are not near vertical discontinuities, or deep vegetation, then differences might be expected. Otherwise maybe it's somethingÂ*corruptedÂ*in his SeeYou, or some bad data in that area, or... and if so something Naviter support should see.

But for those playing along at home. ThatÂ*Brumley Mountain waypoint as already pointed out is hanging off a fairly steep side of the mountain I it should not be a surprise that SeeYou and Google Earth or pick any other (random tools) produce different data. You have to think about where the data comes from and what it is showing.

For the USA I believe Google Maps and Google Earth uses USGS DEMS high resolution LIDAR data sets, with few m lateral resolution. SeeYou used to use the ~global 30m (or 60m?) lateral resolution NASA Shuttle C-band Synthetic Aperture Radar datasets with global coverage, and I suspect they still do, I'd be surprised if Naviter added DEMS data for the USA. (Who wants to buy Andrej beer at the SSA convention to try to get DEMS support for the USA?)

I expect resolution effects here of scale 30m/60m laterally can significantly affect reported altitudes. And when working in SeeYou on Windows you also want to be careful because some of the charts do not resolve sharp features well and it might be possible to place stuff a bit off. But the other critical question is likely vegetation. Do you want to count elevation of the ground surface or of the top of forrest vegetation? What do the software programs and their data sources mean by elevation? The answer there is probably "uh?" :-) The LIDAR data is affected by vegetation more than the C-band data but they try to factor out vegetation, by that may not alway be accurate. (Folks actually measure forrest heights from the difference of LIDAR and C-Band SAR). So where this is critical you better be clear what you mean, and find a way to validate you have an accurate elevation..

For thatÂ*Â*Brumley Mountain waypoint

3,887'Â* Â*Google EarthÂ*7.3.2.5776 (Mac):
3,581'Â* SeeYou (Windows) 10.32Â* Â* Â* Â* Â* :
-----
306' difference
-----

It takes displacing the google Earth waypoint about 180m laterally "down hill" to reach that reported SeeYou elevation. That's not unreasonable given the 30/60 meter resolution, and possible vegetation effects would mean less displacement is needed.

If I drop a way point more up on that flat top of the hill at N36°50.220' W082°05.696'. Google Earth and See You agree more.

3994'Â* Â*Google EarthÂ*7.3.2.5776 (Mac)
3855'Â* Â*SeeYou (Windows) 10.32
-----
139' difference.Â*
-----

I am going to guess a good part of that of that is vegetation effect.Â*

The counter example is to pick locations that have no vegetation and are roughly flat at few x 30m/60m scale and compare them. The easy pick there is airport runways. When I compare the runway intersection at Patrick AFB, FL I get 6 or so feetÂ*+/- few feet. OK that's sea level, so going higher, the runway intersection at Cedar City Airport, UT is 5,999Â*+/- a few feet in either tool. Pretty amazing precision. (Ah memories of irritating a Cedar City tower controller one day and him making me push my DG-303 all the to the end of Runway 8, in the stinking heat. Grrr).

Anyhow precision altitude alway needs to be hand curated, it's great when that is well done. Like when boulder outcrops or mountain top forestry fire lookouts are within feet of the shown elevation on the altimeter. Landing locations are usually relatively easy.

[Darryl Ramm]

On Sunday, February 2, 2020 at 5:26:08 PM UTC-8, soaringjac wrote:
> On Sunday, February 2, 2020 at 1:12:02 PM UTC-8, Darryl Ramm wrote:
> > Post the actual waypoint data here... it’s just ASCII text. Then we have a chance of seeing what is going on.
>
> Here is the waypoint
> "Baden-Powell",Badenell,,3421.517N,11745.883W,2631.6m,1,,,,,,,
>
> actual altitude is about 2865 meters
>
> There is nothing specific about this waypoint, so it really does not matter. Just click around the map in SeeYou and add some random waypoints and then compare to google earth altitudes

Yep you can't do that. The top of that mountain itself is barely the size of a single resolution grid in the NASA SAR data. We could have gotten straight here earlier...

9407' Google Earth 7.3.2.5776 (Mac) (also the official USGS height of the peak).
8634' SeeYou 10.32 (Windows)
-----
773' difference
-----

And the hight resolution Google earth data shows a higher elevation that SeeYou as expected.

Move off the sides a couple of hundred meters and you are at the elevation shown by SeeYou. A bit more that I might expect but that is damn steep terrain.

You really should be using the exact other turnpoint data that other local pilots are using from the Soaring Turnpoint Exchange, it's easy to remove extra turnpoints if you really have to. You don't want any possibility of confusion about location of a turnpoint if talking to nearby gliders. For other peaks I would always try to use the USGS official peak location and elevation data... glider pilots sometimes have amusing habits of creating their own names for less significant mountain peaks (how many "Black Mountains" do I know?).

[Tango Eight]

On Sunday, February 2, 2020 at 9:11:49 PM UTC-5, Darryl Ramm wrote:
> On Sunday, February 2, 2020 at 2:26:56 PM UTC-8, Tango Eight wrote:
> > On Sunday, February 2, 2020 at 4:12:02 PM UTC-5, Darryl Ramm wrote:
> > > Post the actual waypoint data here... it’s just ASCII text. Then we have a chance of seeing what is going on.
> >
> > Here you go. I created this waypoint about 3 minutes ago. Use whatever tool you like to correlate lat/long/elevation. Actual elevation closer to 1220m....
> >
> > "Brumley Mountain",,,3650.274N,08206.228W,1091.5m,1,,,,,,
> >
> > T8
>
> Hi Evan. I was not really asking you for a waypoint. We already discussed this, I hope we both understand why mountainous terrain elevations are likely to not be accurate/disagree like this. I was asking the OP for the waypoints *he* is having problems with. (I see we have a waypoint now, I'll look at that next).
>
> If they are not near vertical discontinuities, or deep vegetation, then differences might be expected. Otherwise maybe it's somethingÂ*corruptedÂ*in his SeeYou, or some bad data in that area, or... and if so something Naviter support should see.
>
> But for those playing along at home. ThatÂ*Brumley Mountain waypoint as already pointed out is hanging off a fairly steep side of the mountain I it should not be a surprise that SeeYou and Google Earth or pick any other (random tools) produce different data. You have to think about where the data comes from and what it is showing.
>
> For the USA I believe Google Maps and Google Earth uses USGS DEMS high resolution LIDAR data sets, with few m lateral resolution. SeeYou used to use the ~global 30m (or 60m?) lateral resolution NASA Shuttle C-band Synthetic Aperture Radar datasets with global coverage, and I suspect they still do, I'd be surprised if Naviter added DEMS data for the USA. (Who wants to buy Andrej beer at the SSA convention to try to get DEMS support for the USA?)
>
> I expect resolution effects here of scale 30m/60m laterally can significantly affect reported altitudes. And when working in SeeYou on Windows you also want to be careful because some of the charts do not resolve sharp features well and it might be possible to place stuff a bit off. But the other critical question is likely vegetation. Do you want to count elevation of the ground surface or of the top of forrest vegetation? What do the software programs and their data sources mean by elevation? The answer there is probably "uh?" :-) The LIDAR data is affected by vegetation more than the C-band data but they try to factor out vegetation, by that may not alway be accurate. (Folks actually measure forrest heights from the difference of LIDAR and C-Band SAR). So where this is critical you better be clear what you mean, and find a way to validate you have an accurate elevation..
>
> For thatÂ*Â*Brumley Mountain waypoint
>
> 3,887'Â* Â*Google EarthÂ*7.3.2.5776 (Mac):
> 3,581'Â* SeeYou (Windows) 10.32Â* Â* Â* Â* Â* :
> -----
> 306' difference
> -----
>
> It takes displacing the google Earth waypoint about 180m laterally "down hill" to reach that reported SeeYou elevation. That's not unreasonable given the 30/60 meter resolution, and possible vegetation effects would mean less displacement is needed.
>
> If I drop a way point more up on that flat top of the hill at N36°50..220' W082°05.696'. Google Earth and See You agree more.
>
> 3994'Â* Â*Google EarthÂ*7.3.2.5776 (Mac)
> 3855'Â* Â*SeeYou (Windows) 10.32
> -----
> 139' difference.Â*
> -----
>
> I am going to guess a good part of that of that is vegetation effect.Â*
>
> The counter example is to pick locations that have no vegetation and are roughly flat at few x 30m/60m scale and compare them. The easy pick there is airport runways. When I compare the runway intersection at Patrick AFB, FL I get 6 or so feetÂ*+/- few feet. OK that's sea level, so going higher, the runway intersection at Cedar City Airport, UT is 5,999Â*+/- a few feet in either tool. Pretty amazing precision. (Ah memories of irritating a Cedar City tower controller one day and him making me push my DG-303 all the to the end of Runway 8, in the stinking heat. Grrr).
>
> Anyhow precision altitude alway needs to be hand curated, it's great when that is well done. Like when boulder outcrops or mountain top forestry fire lookouts are within feet of the shown elevation on the altimeter. Landing locations are usually relatively easy.

Excuses, excuses! This worked much better at about version 4. That was my point. The elevation data served by the SeeYou cloud is relative crap. Very coarse. Probably a good decision on Naviter's part. "Hey, we can save a ton of money on bandwidth, only a couple of ridge soaring pilots will ever notice.
If they do complain, we can probably rely on their buddies to tell them they are being too demanding" :-).

best,
Evan

[Darryl Ramm]

On Sunday, February 2, 2020 at 7:54:57 PM UTC-8, Tango Eight wrote:
> On Sunday, February 2, 2020 at 9:11:49 PM UTC-5, Darryl Ramm wrote:
> > On Sunday, February 2, 2020 at 2:26:56 PM UTC-8, Tango Eight wrote:
> > > On Sunday, February 2, 2020 at 4:12:02 PM UTC-5, Darryl Ramm wrote:
> > > > Post the actual waypoint data here... it’s just ASCII text. Then we have a chance of seeing what is going on.
> > >
> > > Here you go. I created this waypoint about 3 minutes ago. Use whatever tool you like to correlate lat/long/elevation. Actual elevation closer to 1220m....
> > >
> > > "Brumley Mountain",,,3650.274N,08206.228W,1091.5m,1,,,,,,
> > >
> > > T8
> >
> > Hi Evan. I was not really asking you for a waypoint. We already discussed this, I hope we both understand why mountainous terrain elevations are likely to not be accurate/disagree like this. I was asking the OP for the waypoints *he* is having problems with. (I see we have a waypoint now, I'll look at that next).
> >
> > If they are not near vertical discontinuities, or deep vegetation, then differences might be expected. Otherwise maybe it's somethingÂ*corruptedÂ*in his SeeYou, or some bad data in that area, or... and if so something Naviter support should see.
> >
> > But for those playing along at home. ThatÂ*Brumley Mountain waypoint as already pointed out is hanging off a fairly steep side of the mountain I it should not be a surprise that SeeYou and Google Earth or pick any other (random tools) produce different data. You have to think about where the data comes from and what it is showing.
> >
> > For the USA I believe Google Maps and Google Earth uses USGS DEMS high resolution LIDAR data sets, with few m lateral resolution. SeeYou used to use the ~global 30m (or 60m?) lateral resolution NASA Shuttle C-band Synthetic Aperture Radar datasets with global coverage, and I suspect they still do, I'd be surprised if Naviter added DEMS data for the USA. (Who wants to buy Andrej beer at the SSA convention to try to get DEMS support for the USA?)
> >
> > I expect resolution effects here of scale 30m/60m laterally can significantly affect reported altitudes. And when working in SeeYou on Windows you also want to be careful because some of the charts do not resolve sharp features well and it might be possible to place stuff a bit off. But the other critical question is likely vegetation. Do you want to count elevation of the ground surface or of the top of forrest vegetation? What do the software programs and their data sources mean by elevation? The answer there is probably "uh?" :-) The LIDAR data is affected by vegetation more than the C-band data but they try to factor out vegetation, by that may not alway be accurate. (Folks actually measure forrest heights from the difference of LIDAR and C-Band SAR). So where this is critical you better be clear what you mean, and find a way to validate you have an accurate elevation..
> >
> > For thatÂ*Â*Brumley Mountain waypoint
> >
> > 3,887'Â* Â*Google EarthÂ*7.3.2.5776 (Mac):
> > 3,581'Â* SeeYou (Windows) 10.32Â* Â* Â* Â* Â* :
> > -----
> > 306' difference
> > -----
> >
> > It takes displacing the google Earth waypoint about 180m laterally "down hill" to reach that reported SeeYou elevation. That's not unreasonable given the 30/60 meter resolution, and possible vegetation effects would mean less displacement is needed.
> >
> > If I drop a way point more up on that flat top of the hill at N36°50.220' W082°05.696'. Google Earth and See You agree more.
> >
> > 3994'Â* Â*Google EarthÂ*7.3.2.5776 (Mac)
> > 3855'Â* Â*SeeYou (Windows) 10.32
> > -----
> > 139' difference.Â*
> > -----
> >
> > I am going to guess a good part of that of that is vegetation effect.Â*
> >
> > The counter example is to pick locations that have no vegetation and are roughly flat at few x 30m/60m scale and compare them. The easy pick there is airport runways. When I compare the runway intersection at Patrick AFB, FL I get 6 or so feetÂ*+/- few feet. OK that's sea level, so going higher, the runway intersection at Cedar City Airport, UT is 5,999Â*+/- a few feet in either tool. Pretty amazing precision. (Ah memories of irritating a Cedar City tower controller one day and him making me push my DG-303 all the to the end of Runway 8, in the stinking heat. Grrr).
> >
> > Anyhow precision altitude alway needs to be hand curated, it's great when that is well done. Like when boulder outcrops or mountain top forestry fire lookouts are within feet of the shown elevation on the altimeter. Landing locations are usually relatively easy.
>
> Excuses, excuses! This worked much better at about version 4. That was my point. The elevation data served by the SeeYou cloud is relative crap. Very coarse. Probably a good decision on Naviter's part. "Hey, we can save a ton of money on bandwidth, only a couple of ridge soaring pilots will ever notice.
> If they do complain, we can probably rely on their buddies to tell them they are being too demanding" :-).
>
> best,
> Evan

I gather your team lost :-)

It was not that long ago that the 30m NASA shuttle C-band SAR data looked frigging amazing. We are so spoilt.

And like I said Andrej is probably open to a beer or few.... I won't be at the SSA convention but he will and I can't be the only glider pilot who likes beer and SeeYou.

[Martin Gregorie[_6_]]

On Sun, 02 Feb 2020 16:52:59 -0800, Tango Eight wrote:

> It's a ridge route. If you've done any flying of that sort, it'll make
> sense. If you haven't... look at the the topo and do the thought
> experiment.
>
Very little, and that was on steeper, more defined ridges - the ridge
north of Omarama and on the Pennines under Cross Fell. I take your point
about marking the start of a ridge climb.

> https://viewer.nationalmap.gov/basic/?
basemap=b1&category=nbd,ned,nedsrc,histtopo,nhd,naip,nbdmi,gn is,smallscale,nsd,vectorcmb,ntd,ustopo,woodland&q=&zoom=12&bbox=-82.25360870,36.76584198,-81.94805145,36.91201927&preview=&avail=&refpoly=
>
FWIW GoogleEarth can give rather good topographic views if you move off a
bit (1km or so) and then zoom right in, almost to the point where it
wants to switch to streetview. Then moving your viewpoint around lets you
easily pick out high points, ridgelines, etc.


--
Martin | martin at
Gregorie | gregorie dot org

[[email protected][_2_]]

I have create and fixed several turnpoint lists. It is is amazing to see when some people quickly add turnpoints they leave the altitude at O MSL!!!
I scan for this first thing when I redo a list. That could really cause someone to hit the dirt thousands of feet earlier than they thought going to a point.
Chris