GPS Recomendation for Arch Viz

[Sketchrender]

This has been covered before but not in any real detail.

I am looking for a handheld GPS for Visual impact work.

I know this will not be perfectly accurate, but would do for inital work.

 

 

What do you recomend ?

 

How accurate are they........can you get down to 100mm ?

 

How much do they cost ?

 

Where do you recomend buying one ?

 

Thanks

 

I'm in Ireland.

 

phil

[Jeff Mottle]

It's been a while since I looked at GPS, not since I taught GPS navigation and orienteering, but handheld GPS accuracy is limited to approx 10 meters in 2D and 16m in 3D. So you certainly are not going to be able to get 100mm accuracy without some expensive survey grade equipment.

 

In order to achieve the accuracy you are after you will need a differential GPS configuration where you have two separate GPS receivers. One it placed on a benchmark of very accurate known position and the second is the roaming GPS unit. The stationary GPS records errors in position and you later use that data to help remove error from the roaming unit. Accuracy ranges from

 

You can also use less expensive handhelds that supports DGPS (differential GPS) to pick up differential signals from fixed base stations, but the accuracy of the handheld means you likely won't see accuracy much better than 1-3 m. Some locations (cities) and coastlines that have differential stations that DGPS handheld can use to improve accuracy. Check this site out to see current coverages: http://www.navcen.uscg.gov/dgps/coverage/Default.htm

http://www.beaconworld.org.uk/dgps.htm

 

Hope that helps.

[Sketchrender]

Jeff

Thank you very much.

I knew the accuracy would be a problem from the start.

 

Getting a survey done by a professional , seems to be to only method but the price seems prohibitive in some ways, as when you quote for a job the guys with the handheld gps, and disclaimers all over the renders are still getting the work, because the client is looking at the bottom line of a quote and sees that the handheld quote is half of the properly surveyed one.

 

 

Three controll points are not enough in my opinion, but they are being excepted.

 

why?

 

Any thank you , anybody else have experience in anyway please let me know.

 

phil

[Jeff Mottle]

What are you trying to do? A "certified view" ?

[Sketchrender]

jeff

If possible yes, I don't think it is possable with handheld.

Even though they are being done using handheld over here.

 

phil

[Jeff Mottle]

A GPS is not really neccesary to do this if you have a set of survey plans from the city. All you need is a surveyor to go out with a total station to the same position the photograph was taken, and survey the top corners of known buildings or other prominant features in your base photograph that you are going to composite over.

 

The surveyor then sends you a file with those 3D data points which you can then use in 3d studio to align your camera to the photo.

[Sketchrender]

jeff

 

I know that thanks, I am tring to find a way bring the price down so as to reduce the quote prices for the future.

A surveyor here is about 1000 euros a day.

 

phil

[Jeff Mottle]

jeff

 

I know that thanks, I am tring to find a way bring the price down so as to reduce the quote prices for the future.

A surveyor here is about 1000 euros a day.

 

phil

 

 

Ahh I see. Well you could do some reading and rent a total station and do it yourself? Or even rent the differential GPS equipment. If you do it on a regular basis, I bet you could probably take a course or some training from someone like Trimble or Leica, or whoever rents you the survey equipment.

[Sketchrender]

thanks again.

I will have to read up.

 

by the way, is there anything you haven't done.

 

and am i right, somebody said you wrote lightscape many moon ago?

is that right .

[Jeff Mottle]

thanks again.

I will have to read up.

 

by the way, is there anything you haven't done.

 

and am i right, somebody said you wrote lightscape many moon ago?

is that right .

 

 

LOL, yeah I have a short attention span and like to learn a lot of different things. I was also trained to use a LIDAR scanner as well.

 

I definetly did not write Lightscape, although that's a pretty cool rumor, but I was one of the first users. I was however a Discreet forum assistant and answered most of the support questions for Lightscape when it was still being sold. Rod Recker (now managing the Impression program at Autodesk), Stuart Feldman (now owns Cozimo.com), and Filipo Tamparini (I think a programmer at Autodesk now) were the three founders. David Heilman wrote the manual and taught myself and the crew at SMED where I used to work.

[Sketchrender]

very good your no under achiever by any means.

 

thanks again for all your advise.

 

phil