Help needed with Google Earth

I need to establish the amount of fall between a water tank at the Brucknell Scout Camp and the creek through the property to see if its practical to replace a defunct water pump with a solar pump.

My computer isn't good enough to run google earth clearly.
And for some odd reason the elevation readings I am getting on the creek shows that it must be flowing uphill.

The coordinates for the tank are
approx 38 28 21 82 S142 51 33 98 Elevation 269ft
(at the south end of the clearing)
and for the creek
approx 38 28 22 83 S142 51 57 99 Elevation 211 feet

Could someone conversant with google earth please assist

Or you could do it the old fashioned way and get the 1:25000 contour map. Any Boy Scout worth his salt would have one of them for his local area. ;)

NRE promised me a map months ago but time just rolls on.
The water pump died a few days ago and I need to get the water supply working again urgently.
I havent got a sighting level or I would accurately shoot the fall over the half kilometre or so.

Can't you pick up the CMA (or whatever passes for it in Victoria) map? My local newsagent sells all the maps for our area and can get any others in that we need. Or you could buy it online: http://www.themapshop.com.au/site/in...duct_id=164038

about a 40k drive to buy a map.
Jest remembered theres online maps through some govt website, dont know how to find the access.

Neither do I. Would be interested to find out though. Never seen contour maps online.

Doesn't the postman come out your way?

Try emailing the national parks mob or the state forestry commission....or whatever they call themselves over that way.

They may be able to send one via email or at least point you in the right direction.

Cheers
Steve

Bob,

I get the same elevations as you do from Google Earth for those locations, but I don't think elevation data in Google Earth is accurate enough for your purposes. I think you definitely need to get a contour map.

Rocker

Bugger, Rocker just beat me to it....ah well it was good excercise. :D

Try here Bob, youll have to pay though I think.

Al :)

I tried my GPS software and some OziExplorer software and maps I have but the best I have for the area is 1:250,000. You need at least 1:50,000 for something down to that resolution.

I could get some from work but not till mid Jan. You could always ask someone with a gps to drive to the two points and read the result.

OK, can you see in a straight line from your creek to your tank?

If so, then grab a camera that you can see something in the middle of the lens. Grab your protractor square and, at the creek end of things, look through the camera and line the thing in the centre of the lens up with something on the tank the same height off the ground as the camera......measure the angle.
Now if you know the angle and the distance between the creek and the tank you then use trigonometry to find out how far the tank is above the creek.

Or just sight along the rule, keeping the protractor base level.

PM me the distance and the angle and I will give you the height difference.

Bob,

I have discovered that elevations on my GPS are not very accurate which is where I assume your original came from.

What distance are we talking about between the creek and the tank? The accuracy probably only needs to be within a metre.

You could possibly work it out using a hose and water levels.

Perhaps our resident Hydrologist on the Bulletin Board could offer you advice.

I sent your stuff off to my BIL and he reckons the contour data will be too broad to get your result

I can't get anything like a straight line of sight.
While google earth shows about a 70 ft head I really guesstimate its closer to 150 feet or more.

What you need to do is set up a laser level at the tank...





















...and poke a really really really long stick up into the air.:D :D :D

The bottom of the tank is only 30 feet above ground.
The trees must be another 50 or 60 feet higher.
I don't feel like using a laser level on the top of the trees:D :D

According to google the fall is about 60 feet and the tank is 30 feet above ground so if google is only 50% accurate the total head is no more than 150 feet.

The 2" line is about 700 metres long so maybe the fire pump can handle a couple of thousand gallons a day. Its are supposed to have a head capacity of 250 feet. So I think I'll go look at the box of pipe fittings and see what happens when I hook it up.

Trouble is being right on Christmas theres some possibility of no water till the end of january if I don't do something now and theres 100 odd people due in over the next month.

I want to get this monkey off my back quick so I can get back to my shed and finish off my Jan market stock.

Long shot here
Do you have a GPS.
Can you record the NMEA stream? Use hyperterminal.

Record an hour's worth of data at each point.
Post me the text files and I'll try some post processing. Should be able to get accuracies within 5 metres.

Google uses SRTM which has been "thinned" for our area to a point every 30m. The horizontal accuracies aren't that great either. I have seen errors of up to 30 metres. In a relatively hilly area this would upset your accuracies quite a lot.

I can get access to 100k topos, but not at home, so can't help you there.

regards

John Scott

Thanks for the suggestions.
I don't have GPS so that's out.
Spoke to the pump man and he reckons the fire pump shoould do it but that a fire pump will probably only have around a 3 year life cicle against the 40 years the old screw pump lasted. He's not greatly enthusiatic about solar but I might look for a grant for a solar system with a fire pump as a reserve backup,

Thanks to everyone for all the suggestions and advice

Try here Bob.

Al :)

Thanks Al,
Theres bin a few grants around for solar hot water and electricity etc
But I got to feel in the mood to make grant applications.
To do a good application is a lot of work and research.
But when I do extract the digit I usually manage a reasonable success rate:)

Of course if there are any Ministers or Advisers on the bb their assistance will be humbly accepted.:rolleyes:

Quote:

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Originally Posted by echnidna

Of course if there are any Ministers or Advisers on the bb their assistance will be humbly accepted.:rolleyes:

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Sorry mate, wrong state. SWMBO's cousin is a minister in the NSW mob.