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Issue with importing GPS elevation data

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#1
Rhienne

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Hi, I was wondering if anyone could shed some light on what I am doing wrong. I have collected some dGPS data (latitude, longitude and elevation). Lat and long are in the format XX.XXXXXXXXX and elevation data is in the format +/- X.XX m. When I convert this data to a shapefile I am told that my vertical exageration is too high and it has to be modified. Do I need to change the format of my elevation data, and if so, to what?

#2
Melita Kennedy

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Take a look at this thread, Artifacts Gone, Too Dark, which discusses vertical exaggeration issues.

Basically, the xy (lat/lon) values are in degrees while the elevations are in meters. The software isn't that 3D aware. You can either project the data to a projected coordinate system suitable for the area first, or using a scaling on the Z values.

Hope this helps,
Melita

#3
P.Raposo

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Hi, I was wondering if anyone could shed some light on what I am doing wrong. I have collected some dGPS data (latitude, longitude and elevation). Lat and long are in the format XX.XXXXXXXXX and elevation data is in the format +/- X.XX m. When I convert this data to a shapefile I am told that my vertical exageration is too high and it has to be modified. Do I need to change the format of my elevation data, and if so, to what?


I think another way to go about that, as long as you've got that dGPS data in a table format like excel or csv, is to add it to ArcMap as a table, and then using the "plot x,y" function available by right-clicking on the layer in the table of contents. Plot by your lat and long values, making sure to select the right "coordinate system," which, in Esri's terms, is both a datum and a projection. I think you want something based on the WGS 1984 datum, since that's what GPS uses (I'm slightly uncertain only because I don't know that the "d" is for). Doing this should get you a layer of "events" plotted, which you can export to shapefile, having not changed the values in your elevation column at all.

Also, see that ArcMap keeps that elevation column in a number format like double or float, so you can keep those decimal numbers.

Hope that helps :)




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