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Author Topic: Elevation in feet but Basecamp shows meters  (Read 1311 times)

Boyd

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Elevation in feet but Basecamp shows meters
« on: January 21, 2018, 04:18:31 AM »
I have an odd problem that I just can't figure out. Looking at a map I made a few years ago, all the elevations are too high. On closer examination, it appears that Basecamp (also Mapsource) think the elevation units are meters when they should be feet. So all the numbers are 3.25 times too large. For example, an elevation that should be displayed as 80 is actually shown as 260. I have Basecamp units set to feet in the preferences. If I change the preference to meters then it shows an elevation of 80 meters.

The map was created in Globalmapper and correctly shows the elevations in feet. I export as an MP file, it appears to be correct in GPSMapEdit. Here is the header

IMG ID]
ID=90007252
Name=20150210
Elevation=F
LBLcoding=9
Codepage=1252

Here's an example contour line

POLYLINE]
Type=0x21
Label=85
EndLevel=0
Data0=(39.9754639,-74.5803986),(39.9754639,-74.580513),(39.9754448,-74.5805893),(39.9753723,-74.5806808),(39.9753723,-74.5807724),(39.9754639,-74.5806808),(39.9754639,-74.5803986)
[END]

What could be wrong here? If I look at another MP file that shows the correct elevations, I don't see any difference
« Last Edit: January 21, 2018, 04:35:50 AM by Boyd »

Boyd

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Re: Elevation in feet but Basecamp shows meters
« Reply #1 on: January 21, 2018, 05:44:34 AM »
Digging deeper, it seems that the problem must come from Globalmapper. I realized that I had the Preferences set to meters in GPSMapEdit, so I changed that to feet. And now GPSMapEdit is also showing 265 feet when it should be 80 feet.

But everything seems to be correct in Globalmapper. It has elevation units set to feet and displays the correct numbers. So something is going wrong when I export to MP files.

Boyd

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Re: Elevation in feet but Basecamp shows meters
« Reply #2 on: January 21, 2018, 06:43:55 AM »
So I made a really simple globalmapper file that only contains one contour line with an elevation of 100 feet. If I export it as an MP file, it is interpreted as 100 meters and converted to feet however. This is the contents of the MP file

Code: [Select]
[IMG ID]
ID=90007259
Name=
Elevation=F
LBLcoding=9
Codepage=1252
Marine=N
Copyright=
Preprocess=F
;TreSize=3000
POIIndex=Y
Transparent=N
Levels=4
Level0=24
Level1=22
Level2=20
Level3=18
Zoom0=1
Zoom1=2
Zoom2=3
Zoom3=4
[END-IMG ID]

[POLYLINE]
Type=0x22
Label=328
EndLevel=2
Data0=(39.9683342,-74.5985947),(39.9684372,-74.5986328),(39.9686165,-74.5988235),(39.9688721,-74.5993118),(39.9691048,-74.5996323),(39.969635,-74.6000214),(39.9697113,-74.6001434),(39.9697533,-74.6004105),(39.9697342,-74.6005936),(39.9696045,-74.6007767),(39.9695053,-74.6007996),(39.9694366,-74.6007767),(39.9692917,-74.6003647),(39.968895,-74.5998383),(39.9687614,-74.5995102),(39.9686546,-74.5993347),(39.9682503,-74.5988159),(39.9682388,-74.5986404),(39.9683342,-74.5985947)
[END
]

But if I export it as a shapefile, this is what appears in the .dbf. (see attached). I must be missing some globalmapper preference, but I can't find it and never had this problem before.

Boyd

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Re: Elevation in feet but Basecamp shows meters
« Reply #3 on: January 21, 2018, 06:55:34 AM »
OK, never mind, I found the problem but it was pretty obscure. Maybe this will help someone else (does anyone else even use Globalmapper anymore?).

Double-clicking the layer with the contour lines in the Globalmapper control center has an option for elevation units that appears to over-ride the other settings. Here's a screenshot. The elevation units were meters here originally, changing this to feet fixed the problem. Geez... ;)

I suppose the problem was that I had "massaged" the contour line data so that the name was the only item that indicated elevation.

« Last Edit: January 21, 2018, 06:57:25 AM by Boyd »