Exported Contours- Proper Z values, untrue X dimensions

[MatthewPoot]

I've been trying to export some contours generated for a 30km square area, from arcMap 10.3 to both AutoCAD and Civil3D, with no success in either DWG or DXF format.

I have followed these, and similar instructions:  http://maps.library.utoronto.ca/docs/Exporting_Contours_from_ArcMap_to_AutoCAD.pdf

I have generated the contours using spatial analyst, with the extension on, and everything works well except that the X-axis data is .000006% of the size of the actual scaled area.  I've tried adjusting the projection settings in Civil3D, to match those in ArcGIS, to no avail

I've attached a screenshot of what happens due to the mismatched scaling, so perhaps someone here might have a tip?

[AdrianWelsh]

Hi Matthew,

This sounds like it might be a projection issue. When you first dealt with your original data in ArcMap, were you able to verify that things looked "normal" to you? Meaning that the spatial data was where it was supposed to be initially? The way I do this is to add a simple basemap behind my data just to visually check this.

I would also attempt to validate the data after the geoprocessing as well to see if it is where it is supposed to be. If your initial data is not appearing in the right place then you may have to mess with the coordinate systems of your data to make sure it is being projected properly.

[MatthewPoot]

I've used the world imagery service as the backdrop, although even the original files for the DEM were in WGS 1984 format.

I also have set the AutoCAD workspace to operate in the same coordinate system, and no result change.

[DanPatterson_Retired]

Well, your X,Y coordinates are in decimal degrees... East west somewhere in the range -180 to +180 degrees and 90 to -90 North South.  These data need to be projected to a projected coordinate system appropriate to your area (perhaps a UTM or the like) This will get the XY values in the same coordinate system as the elevation.. which is in meters I hope otherwise you will have the feet versus meters thing to deal with as well

[MatthewPoot]

right...  well, my area occurs across the boundaries of two UTM tiles.  Indeed, the x-values are in degree units, rather than meters, at least when I'm looking at redifining the area in define-query functions.

I've got to head back to my home computer for the evening, but might you know the best way to make this transformation:?

[DanPatterson_Retired]

Examine the layer's properties and determine the extent (left, right, bottom, top) of the layer.

Do the values look like they are in decimal degrees? if so are they appropriate for the location you are working with?

Do they look really large? if so, do you know the projection for the file?

Are the numbers really weird and look like they might be in a relative CAD scaling where it is just a drawing with no direct link to the real world?

That information would help in narrowing down your problem

[MatthewPoot]

I would say that it is something in the direction of CAD scaling, but I have set the appropriate coordinate system (LL84), and it just seems like the extents (x-coordinates) are way off, and I cant figure out how to resize the thing accurately.

Currently, my area within AutoCAD is about .25 units squared, with proper elevation, yet in true size it is ~30 km across.