Topic: Import from Google Earth

[Guest]

How does the drawing scale (from the Drawing Settings dialog box) relate to the size or amount of area imported from Google Earth?  Does the zoom factor in Google Earth play a part in how much is imported?

I had my drawing scale set to 1"=20' and was zoomed into the area I wanted to import.  I was expecting something more than the 100'x100' piece of land (surface) to come in and the image from GE was huge in comparison (about 15 X's larger than the surface).  I then messed around with the drawing scale (set it to 1"-200') and the next time I imported from GE, I got more of what I was expecting to get from the first go around but with the same image size from my first attemp.  So... In order to get more area imported, I have to up the scale factor?  I haven't had much time to play around with importing GE terrain because it's installed on another computer which is used quite frequently by others.

[Greg B]

I find Google Maps works better then google earth when using the scale onscreen.

[Jeff_M]

I dunno Matt. I just tried it on a site where I was zoomed in close to a 150x 250 parcel, than out so I saw for a half mile all around it. I had 2 images and 2 surfaces that each matched exactly what I was looking at in GE.

You should be getting GE to view what it is you want imported, then go to C3D and import....no need to be viewing the area in question in C3D as it will automatically zoom there on import. Make sure your Zones are set correctly, too, in C3D.

[FengK]

Jeff, Based on your experience, how accurate are the surfaces from Google Earth as far as elevation is concerned? Thanks.

[Jeff_M]

For ROUGH planning they are pretty good, as well as for large drainage studies. They aren't anywhere near close enough for much more than that. Kind of like when we used to used USGS Quad maps as a part of our Hydrology maps for long reaches.

[mjfarrell]

My observation of the accuracy of the GE derived surfaces is that they might be fine for PRELIMINARY design studies only.  Anything further should be done with surveyed data.

[Guest]

I dunno Matt. I just tried it on a site where I was zoomed in close to a 150x 250 parcel, than out so I saw for a half mile all around it. I had 2 images and 2 surfaces that each matched exactly what I was looking at in GE.

You should be getting GE to view what it is you want imported, then go to C3D and import....no need to be viewing the area in question in C3D as it will automatically zoom there on import. Make sure your Zones are set correctly, too, in C3D.

What's your drawing scale set to?  I've found that that, for some reason that I don't understand, makes a difference.  Unless there was a "hiccup" during the import process.   

When I had it set to 20 scale, the surface object was rather small compared to the image.  When I changed it to 200 scale, the surface approximately the same size as the imported image. 

[Greg B]

A neat alternate to GE and VE

Kinda


http://www.flashearth.com/


It does use flash.

[Jeff_M]

Hi Matt,
It doesn't matter what my dwg scale is. The Image & Surface are always the same size, which is always the same as what I was viewing in GE.

Time for a version & sp check.....
I am using C3D2008, SP2 & GE 4.2.0198.2451 (Sept 2007)

[Guest]

Hi Matt,
It doesn't matter what my dwg scale is. The Image & Surface are always the same size, which is always the same as what I was viewing in GE.

Time for a version & sp check.....
I am using C3D2008, SP2 & GE 4.2.0198.2451 (Sept 2007)

C3D - SP2
GE - Unknown at this time.  I'll report back later when I can get on the computer.  I do know it's at least 4.X.

[FengK]

I only tried importing from GE into C3D a couple of times. The surface was imported at the correct size, but the image was 12 times larger.

[surveyor_randy]

I've never had this issue that you all are experiencing.  A quick question, why would anyone want to use a google earth surface?  They are wwwwaaaaaaaaayyyyyy inaccurate!  And everytime that I've used one to prepare a bid, it doesn't even show features that are there.  Just get the DEM from the USGS.

[Jeff_M]

It took a bit over an hour to create the drawing with a surface from a DEM that looks like carp. It IS about 3' closer in elevation to real elevations than the GE surface (which is about 3' too high), but for a quick "here's how your site looks now", I'll stick with the GE surface that took just under 2 minutes to create.

Here's a pic of the 2 combined. The contour labels with the oval borders are from the GE surface, the others are from the DEM.

The whole key here is KNOWING that the GE surface is not accurate and using at a visualization tool only. Used in conjunction with the aerial image, it CAN be a useful tool. Another thing to bear in mind is that these images, and the associated DB's are only updated every 1-3 years (or more, depending on location).

[FengK]

When importing an image from GE, it can only be black and white?

[mjfarrell]

you were expecting?   however a side effect is that the resultant bi-tonal image can be faded.