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google earth imagery question


chow choppe
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hi

 

we are working on a 3d development of a road network running over a canal which is around 10kms long.

we found the image on google earth pro and we want to know how can we take the image from google earth of a 10km X 10km area at best resolution and start drawing on it taking it as reference.

we would want to get this image to 3dsmax and start drawing flyover, roads bridges over the required ares

 

Thanks

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Since the google maps are composed from images coming from different satelites one can not give an exact height at which resolution is best. So you have to see the best height for your location by experimenting. Beyond a certain height the map does not update anymore. Since GE Pro saves out the viewport to a max. image size of 4K it depends on your monitor size how much you have to zoom out to get the optimal resolution. With 10km you probably have to stitch images together in PS !!

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I've been doing some playing with stiching together large compositions from GE (amateur, not pro ;-) just with screen capture.

 

One warning - turn off terrain before taking images. The image gets distorted enough by perspective on the terrain that stitching becomes difficult. Though a good software solution might work where doing it by hand fails. Still, that would "work" because the software warps the images.

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  • 5 months later...

A useful reference:

 

I think you should take a look in Plex.Earth Tools for AutoCAD which can give you the solution. That's an AutoCAD plug-in which can create a mosaic of color images from Google Earth and has also some very useful features (e.g zoom Google-E in a region specified in AutoCAD).

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Dear quizzy,

 

This is completely useless for engineering design!! (but I would recommend it to web designers and graphic artists for poster creation)

 

I am a civil engineer, and I have to have in mind two old fashioned principles:

 

1. Earth is a sphere

2. I need imagery to be georeferenced in my coordinate system

 

So, if I want to do my work, I'd use Plex.Earth.

 

PS. "Stiching" is applied in geodesy and topography for more than 20 centuries. That's the basic idea behind coordinate systems...! Do you believe you don't need it anymore and it's time to change it?

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we want to know how can we take the image from google earth of a 10km X 10km area at best resolution and start drawing on it taking it as reference.

 

Lambros, it helps if you read the question before answering and render my solution useless. It might be useless for you (and I understand why) but thats not what the initial question was...

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@quizzy:

It was just a little "weird" for me (as an engineer) to hear that stiching is "old school" method... :confused:.

 

How could be, since Google Earth/Maps tilling is actually stiching and as I said before any other mapping application last 20+ centuries!!

 

I have read the initial question, that's why I recommended the use of Plex.Earth at the first place.

 

Even if it's only for rendering purposes, the best solution (I think) is to use georeferenced background because it's easier to import road and bridge models from the original drawings. So, I assumed that 3dsmaxed was talking for georeferenced imagery of a 10km x 10km area at the best resolution, which can be easiliy achieved with Plex.Earth creating a mosaic.

 

 

PS. I don't consider your solution useless. Actually, I already sent your link to some friends that could be useful to them. :)

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If you want hi-res imagery, you can always use the same source material Google does. There are a number of GIS sites, many of them government-run, where you can get ortho-corrected imagery, as well as a lot of vector data with topos, roads, building footprints, water... Those can be translated out to DXF. The imagery can be output to TIFF, 3D heights in DEM-type files (they go by several names) can be output as a 3D mesh. There are lots of options that go well beyond what Google shows.

 

To work with all those weird GIS filetypes I use GlobalMapper:

http://www.globalmapper.com

it reads just about everything, layers raster and vector together, outputs to useful formats and, of course, georeferences to about every known coordinate system in use anywhere in the solar system. It includes the systems used for Mars and Venus, for example. Those might come in handy, though I doubt it.

 

I have also used GoogleMaps and Microsoft LiveLocal maps as base imagery for laying out a project. I have found their stuff to be as good as anything I've obtained in GIS. The problem has been stitching the images. Now, thanks to Quizzy, I don't have to. Nice!

 

Still, the easiest way to get full resolution (which may be 1m, 10m 3m or sometimes .66m) is to use the native GIS orthos and output 1:1

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@Ernest Burden:

 

Global Mapper is a very nice and well known program. There are plenty of nice programs but I use any of them where it can give me the most. So:

 

1. Recently I was working in a road 180 km long and I was bringing imagery as a background. Would you do it by georeferencing one image? Try to measure the inaccuracy...! Plex.Earth simply scans the whole area I need and bring images in AutoCAD creating a mosaic with the best accuracy I could get. So....

 

2. As you say "the easiest way to get full resolution is to use the native GIS orthos and output 1:1". Indeed, this is the easiest way but you have to spent a loooot of money to get the a decent resolution. So...

 

3. Have you ever tried to apply the workaround quizzy suggested? Nice workaround, but it's a real pain to georeference it and do your work. And I want to do my work in just a few minutes. With Plex.Earth it only takes a few seconds to bring images from Google Earth in AutoCAD. So...

 

So, I don't want to spent money, time, and pain. I also want to get the highest quality. That's why, when I work in AutoCAD (even in vanilla) I use Plex.Earth

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