Surveying my Garden

windsor · Occasional Visitor Joined: Feb 25, 2004 Posts: 51

OK Chaps, Here's the problem.

I have an accurate scale drawing of my garden, with 3 positions marked on it which are fixed positions on the ground. (corner of buildings etc.)
Is there any software that runs on Pocket PC, with GPS etc, that will allow me to scan the drawing, stand on the known spots to calibrate it, and thus check the positions of the boundaries, etc. by walking to the appropriate place, with moving map display on the pocket pc. (I understand the limitations of accuracy with the standard GPS signal & can accept this.)

any ideas

Geoff

barryd · Posted: Wed Apr 06, 2005 5:28 pm Post subject:

You could try OziExplorer. To create your map, you'll need to be able to:
- scan in your paper drawing to create a bitmap file (in png, jpg, gif, bmp etc. format as you prefer)
- take your positional readings using the GPS
- Using OziExplorer for PC, load the image and calibrate it from your readings
Having created the map, you can view and use it on both the PC and Pocket PC applications.
See http://www.oziexplorer.com/ for more info, and trial downloads.
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Barry Davies

windsor · Occasional Visitor Joined: Feb 25, 2004 Posts: 51

Hi,
Many thanks,
I was hoping for something, that having scanned the drawing, and put it in my pocket pc, as a graphics file, all the rest (calibration etc)could be done on the pocket pc.
Is this possible?

Geoff

Leif · Occasional Visitor Joined: Apr 04, 2005 Posts: 16

Garmap CE can do it but is a little tricky to learn.

Darren · Posted: Wed Apr 06, 2005 10:01 pm Post subject:

Not sure if you can calibrate on the PPC, most use a PC util for this. Pathaway has an excellent PC calibration application and works well.
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Darren Griffin

barryd · Posted: Wed Apr 06, 2005 10:18 pm Post subject:

You could look at this, if your garden is in the UK:
http://www.callnetuk.com/home/shanks/GPSMap.html
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Barry Davies

lbendlin · Posted: Wed Apr 06, 2005 10:48 pm Post subject:

LocBrowser has a relatively decent calibration feature for use on a Pocket PC. The UI takes a bit to get used to, but it does the trick.
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Lutz

Report Map Errors here:
TomTom/TeleAtlas NAVTEQ

windsor · Occasional Visitor Joined: Feb 25, 2004 Posts: 51

Many thanks for the replies,

Unfortunatly, (as far as software goes! 8) ) the garden in question is in the French Alps, and I don't yet have access to a PC when there. I will give Lutz's suggestion a try & let you know the results.
One of the reasons for the question is that the land is at 30-40 degrees to the horizontal, (and not all in the same plane), and I want to see what difference a GPS survey makes compared with measurements on the ground.

once again,
Many Thanks
Geoff

oddsock · Posted: Thu Apr 07, 2005 11:59 am Post subject:

windsor · Occasional Visitor Joined: Feb 25, 2004 Posts: 51

Thanks for the link Dave; thats what i would have expected - you can imagine how much I am looking forward to discussing this with a non english speaking 'expert geometre'!

On another note I have now experimented with LocBrowser, Lutz, and if you think the GUI is dodgy, you should try Cartoexploreur!.

I have made a local map to try it out, (a screen print from Autoroute, which I know won't be accurate), and it displays ok until I calibrate it, when the map distorts, to give a view reminiscent of a Tomtom 3d view.
Any ideas? (I have yet to try moving the calibration points further apart, which may do the trick)

Geoff

barryd · Posted: Fri Apr 08, 2005 2:16 pm Post subject:

I've had a quick play with LocBrowser, just out of curiosity.

I suspect your problem is its grid, which looks to be in lat/long units rather than distance units. For example, if you have a square 1km x 1km graphic grabbed from a map, then LocBrowser stretches it into a rectangle because in its grid format this map covers around 3 secs of latitude by 6 secs of longitude. (My example is exaggerated for the French Alps area, but makes the point.)

From my quick look, I can't see a way around it with this product - apart from moving your garden to the equator, which is a bit drastic.

Someone else may know this product better, of course.
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Barry Davies

windsor · Occasional Visitor Joined: Feb 25, 2004 Posts: 51

Thanks Barry, you may well be right.

I have recalibrated my trial map with more widely spaced points, but it actually made the distortion worse. Anyone with experience of LocBrowser out there?

I could consider moving my garden to the equator, but of course you need different base wax on your skis for sand!
Wink

Geoff

windsor · Occasional Visitor Joined: Feb 25, 2004 Posts: 51

Further report on LocBrowser;

The problem seems just to be one of accuracy in calibration. I have recalibrated my trial map using the position output of Autoroute, and all seems well now - a not very distorted map results. Trying to calibrate in the field, in the cold, does not produce such good results, so LocBrowser is obviously very 'twitchy'.

Geoff

BBB · Regular Visitor Joined: Feb 24, 2004 Posts: 206

It is really wonderful having so much choice!

I did not know so many were available

The one I tend to rely on is none other than GPSU GPS Utility

uglybloke · Occasional Visitor Joined: Dec 17, 2005 Posts: 3

The easiest way to overcome your problem is to use gps to give you a fixed point in your garden and then find another point as far away from the first point.

You can then correct the second position by actually measuring the distance from the first point.

Then use basic trig to pin point the position of all things in you garden.

This should give you an acuracy of millimeters.

This is basic surveying stuff, If you use a CAD. (computer aided design) package for gardens you should be able to build a very accurate model of your garden.

All you then need to do is find out the actual position of you start point.

Hope this helps

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