streched maps with Geographical Coordinates

[reini]

Hello,

when open Data files (like .GPX) with Geographic Coordinate System, they look quite strange (stretched longitudinally). That's because Global Mapper don't account for the shortening of longitude depended on it's latitudial position.

When switching the projection to UTM, the map looks quite ok again. Is it possible to implement this shortening for Geographic Coordinate system in some way, at least approximately?

I think for most useres it is an advantage to see their maps in a shape they are used to know and not with such a streched look.

[global_mapper]

The way to avoid the stretch is to change the view projection, as you noted when switching to UTM. If such a stretch was added to the Geographic Coordinate System then it would no longer be that coordinate system, but would be something else. Each coordinate system has its own advantages and disadvantages, so it is up to the user to weigh those and choose the most appropriate one for their data.

Thanks,

Mike
Global Mapper Support
support@globalmapper.com

[reini]

the problem is, when I'm using UTM-projection just for desktop-viewing and I want to export the data as ASCII-Textfile, the export-projection is UTM too and not Geographical coordiantes which has been the import format.

Is is possible to just view data in UTM but to export it in its original import-projection (in my case: Geographical coords?), without the need to switch Geographic --> UTM --> Geographic within Configuration/Projection with every new loaded data?

[global_mapper]

All exports will always be done in the currently selected projection on the Projection tab of the Configuration dialog, so if you want Geographic exports you'll have to either set it there, or perhaps you could write a script file that you could run when you want to export that sets the projection to Geographic, then does your export. See Global Mapper - Scripting Language Reference for details on the scripting language.

Let me know if I can be of further assistance.

Thanks,

Mike
Global Mapper Support
support@globalmapper.com

[tonyk]

<Bump thread> I've got the exact same problem, want to view a map undistorted in UTM but also want to export points and lines as Geographic.

reini, did you write a script for this?

Mike, Any chance that GM might someday support picking a different projection when exporting?

[global_mapper]

I suppose we might one day add an option on the export dialogs to change the projection right there rather than having the user always go to the Projection tab of the Configuration dialog. However since there is already a way to change the projection (it just changes the view and export projection, so what you see is what you get), this would be a lower priority than adding new functionality.

Thanks,

Mike
Global Mapper Support
support@globalmapper.com

[fluvial]

I am importing quite large .adf files (Arc/Info Binary Grid). The result is a vertically (longitudinally) stretched image. The original files appear to be in Transverse Mercator. I have tried changing the projection of the files on the Options in the Control Center menu, and also changing the projection in the Configuration menu. Seems that others get rid of stretching by changing to UTM, but I have no such luck. Any suggestions?

[global_mapper]

How large exactly are your files? There was a problem dealing was huge Arc Binary Grids (i.e. over 2GB) that was recently fixed. This problem would have caused a partial display and vertical stretching. I have placed a new build at http://www.globalmapper.com/global_mapper11.zip with this fixed for you to try. Simply download that file and extract the contents into your existing v11.xx installation folder to give it a try. If you are using the 64-bit version, there is a new build available at http://www.globalmapper.com/global_mapper11_64bit.zip .

Let me know if I can be of further assistance.

Thanks,

Mike
Global Mapper Support
support@globalmapper.com

[fluvial]

Thanks Mike. The files are 1.8 GB each. Maybe the problem I have is that I am using V10. I have a 64 bit computer - will upgrading to V11 fix this and generally improve speed of working with these large files?

[global_mapper]

Upgrading to v11 and using the 64-bit version should definitely speed things up for you, plus you could access the fix for very large Arc Binary Grid files.

Let me know if I can be of further assistance.

Thanks,

Mike
Global Mapper Support
support@globalmapper.com