measure and elevation

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jay jay
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measure and elevation

Hello Glenn,

How to validate measurements  on plane and terrain made by osgearth tools?

regards,
Jai
jay jay
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Re: measure and elevation

This post was updated on .
Hello,

Please comment whether these tools do accurate measurements?


Actually, qgis / arcgis measurements show 400 m whereas osgearth_measure only shows 288m

why so?


regards,
Jai
gwaldron gwaldron
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Re: measure and elevation

What tools? What measurements? Please provide complete information about what you are trying to do.
Glenn Waldron / Pelican Mapping
jay jay
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Re: measure and elevation

Hello Glenn,

I am talking about osgearth_measure.exe 

On Feb 12, 2018 19:00, "gwaldron [via osgEarth]" <[hidden email]> wrote:
What tools? What measurements? Please provide complete information about what you are trying to do.
Glenn Waldron / Pelican Mapping



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gwaldron gwaldron
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Re: measure and elevation

The osgearth_measure example just uses the GeoMath::distance function, which calculates a great-circle distance on a sphere. So it only approximates the distance along the earth's WGS84 ellipsoid.
Glenn Waldron / Pelican Mapping
jay jay
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Re: measure and elevation

Hi
Is it possible to have accurate measurement? Pls suggest a way out

On Feb 12, 2018 23:58, "gwaldron [via osgEarth]" <[hidden email]> wrote:
The osgearth_measure example just uses the GeoMath::distance function, which calculates a great-circle distance on a sphere. So it only approximates the distance along the earth's WGS84 ellipsoid.
Glenn Waldron / Pelican Mapping



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jasonbeverage jasonbeverage
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Re: measure and elevation

Hi Jay,

If you want to do true point to point measurement in 3D you can just use the Vec3d class.  Have the user click two points on the earth, a and b, and then the distance between them is:

double distance = (b -a).length();

Jason




On Mon, Feb 12, 2018, 9:27 PM jay [via osgEarth] <[hidden email]> wrote:
Hi
Is it possible to have accurate measurement? Pls suggest a way out

On Feb 12, 2018 23:58, "gwaldron [via osgEarth]" <[hidden email]> wrote:
The osgearth_measure example just uses the GeoMath::distance function, which calculates a great-circle distance on a sphere. So it only approximates the distance along the earth's WGS84 ellipsoid.
Glenn Waldron / Pelican Mapping



If you reply to this email, your message will be added to the discussion below:
http://forum.osgearth.org/measure-and-elevation-tp7591641p7591647.html
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NAML
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