## GeoMedia

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Occasional Contributor
Posts: 18
Registered: ‎11-03-2017

# Polar projection line between points

When working in a projection such as Universal Polar Stereographic a line connecting two points would actually be a curve with a changing bearing, similar to Great Circle.

In Mercator projection the line between points is always straight with a constant bearing.

Is it possible for GeoMedia to render the lines connecting points as Rhumb lines when in a Polar projection, which due to the projection would look like a curve?

The underlying code handles the calculation using geographic locations so it is only the visual rendering of the line shown on the map view that we would like to change to maintain consistency with the rest of our code and for when we work in Mercator

Occasional Contributor
Posts: 18
Registered: ‎11-03-2017

## Re: Polar projection line between points

Hello,

Anybody have any ideas if this is possible?

Basically we create a straight line between two geographic points in Mercator.

Then change the projection to Universal Polar Stereographic.

We still observe a straight line connecting the two geographic locations.

What we would like to know is if GeoMedia has a way of showing the actual line connecting the two geographic points as a curve, as it would actually be in reality in polar projection?

Many thanks

Technical Evangelist
Posts: 307
Registered: ‎02-03-2016

## Re: Polar projection line between points

No, this capability does not exist in GeoMedia.  Vertices are always connected by straight lines when rendering a polyline or polygon.  You could experiment with densifying your polylines before reprojecting to determine if they are keeping the shape that you wish.  If that seems at all promising, go to the Functional Attributes command and check out the DENSIFY expression function.  - Hal

Staff
Posts: 131
Registered: ‎05-27-2016

## Re: Polar projection line between points

[ Edited ]

I did something similar with a Spatial Model, I used the great circle equation in a SM to calculate points between 2 locations.

Heres a picture of the line and computed points shown in Mercator and Gnomonic projections around Australia.

I simply saved the points to a text file then used GM to geocode.

However with GM now you could pass the line feature to an SM and write a new line.

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