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DXF Contour Lines misaligned in AutoCAD Civil

The learning grind with Pix4D and getting useful data out continues. In QGIS, I can easily align a set of contour lines on top of the orthomosaic. This is probably because neither is geolocated and align at a 0,0 insertion point or (as I hope), both are geolocated at the same point.

In AutoCAD Civil 3D, after setting the correct coordinates system, I am able to insert only the tiles from the Orthomosaic as the merged file (~750MB) is reported as an invalid file. Notwithstanding that I have yet to work out how to merge the tiles to remove the tile borders (another thing to learn), when I insert the DXF contour line file, the file is not seen. Zooming to extents makes everything ‘disappear’ and it transpires that the two objects are - quite literally - miles away. Each one appears as a single pixel and scrolling and scrolling in on each one reveals it to be either the contours or the orthomosaic. 

It’s only right to point out that I’m an AutoCAD virgin and every piece of online support assumes a level of knowledge that I clearly don’t have. That said, I can’t fathom why two outputs from Pix4D, taken from the same space on the earth are deemed so far from each other in AutoCAD - anyone have any advice for me (other than “don’t give-up the day job!”)?

Jaimie - to remove the tile borders, set your IMAGEFRAME value to 0 or 2. Zero will turn them off completely, whereas a value of 2 will leave them on (good so you can still select them), but won’t print the borders.

As for the image, Civil 3D won’t insert an image over 500mb. If you use a program like GlobalMapper or QGIS to convert the image to ECW format, you’ll see that the image size is greatly reduced, and you can insert it as a single image.

As for the contours and images being far apart, try this:

  1. Open the DXF file of the contours, and set the coordinate system using the toolspace palette
  2. Use the MAPIINSERT command to insert the image, either the tiles or the ECW file you created
  3. This should then align everything properly.

If you’re still having troubles, I’d be happy to take a look at your files and see what’s going on.

-Mark Blacklin

Mark, you are a scholar and a gentleman. Thank you.

The three-point process you outlined above worked perfectly well for me. At first I was a little concerned because although the two objects (raster map and contour DXF) were visible in the same screen, they were still about 7,000 feet apart. It turns out this was due to an imperial/metric mismatch and once the two were using the same space, they aligned perfectly. I was not able to get the contour labels to appear and had a similar problem in QGIS. The fix for the latter was to import the *.shp file instead of the DXF and I I’ll experiment with another trial data set I’m working on.

The information about the size of the image that can be inserted is truly what was my Achilles’ heel. I have a demo copy of Global Mapper and while not inexpensive at $500 is likely to be a worthwhile investment.

Thanks so much, I really appreciate you helping me out on this, you’re very generous. If I’m ever fortunate enough to be in the 50th State, I’ll be sure to look you up and buy you a beer or two!