Georeferencing for Land Managers

[Kiril]

To continue the recent threads from Fimco on tools for water and land management, lets touch on Georeferencing.

The recent discussion on soil moisture probes included a unit (Fieldscout) that also offers an accessory add-on for a GPS unit.
Now this is a very nice feature, but the unit they show being used with the unit (Garmin GPS 72) is not going to cut it given the best positioning accuracy it can obtain is 3m (WAAS).

Then there is also the question of repeatability, or how close to the same location can I get on repeated visits. For something like water audits and utility marking, a sub-meter or sub-foot unit would be the best choice, but they are anything but cheap.

The choices as I see it are pretty much limited to two areas, land surveying or mapping. There are also some Ag units that might do the job.

The unit I have been looking at is a mapping unit produced by Trimble and has sub-foot accuracy.

Trimble GeoXH (http://trl.trimble.com/dscgi/ds.py/Get/File-414893/022501-162A_GeoXH_DS_0608_MGIS_lr.pdf)

and the sub-meter model.

Trimble GeoXT (http://trl.trimble.com/dscgi/ds.py/Get/File-414895/022501-164A_GeoXT_DS_0608_MGIS_lr.pdf)

If anyone here has experience with either of these, or any other type of high accuracy GPS units please chime in.

[Kiril]

A field test report on several sub-meter receivers that I found last week.

http://www.starpal.com/Reports/Submeter_GPS_Report_e.html

[Wet_Boots]

Get it under half-a-meter, and those missing valves will be easier to find.

[Waterit]

Maybe someone will develop a GPS-transmitting solenoid and 521's will go the way of the Pony Express.

[Wet_Boots]

Build in a core of mercury fulminate, and when the solenoid overheats, it blows open a crater, for easy access. :)

[FIMCO-MEISTER]

Missed this thread somehow. I will have to hit it with coffee in the morning. I'm more interested in the GPS for recording moisture and soil data than lost valves. Lost valves are so yesterday. Modern irrigation is soil knowledge, plant knowledge, and water management.

[bicmudpuppy]

My best understanding on the cost of a sub-foot unit was in excess of $3K. A unit that could reliably re-produce sub-foot results with axillary computer geometry can probably be acquired for $500-$1K. I spent some serious time with the ag extension agent at my course in KS when we did some soil sampling. He did a research paper on precision ag and used the data from my soil samples. I got free samples, he got some great data that was on a small enough scale site to make it manageable. We started the data with an older trimble unit (purchase cost around $3K, current value less than $1K), but he upgraded units during the project. New unit was sub-foot. Old unit needed the computer enhanced geometry. Satellite geometry went over my head. I did finally grasp the basics, and I was going to take the course he offered through the extension office, but he moved. (and then I moved) A 3M unit can be much more accurate IF you spend some time. IF you can visit the same site multiple times, you greatly increase the units accuracy. Plot 8-10 points from the exact same spot and the average will get you sub-meter, if not sub-foot. The location and number of satellites sampled makes a big difference. A unit that promises 3m accuracy will be accurate regardless of what satellites are available and what positions they are in. (unit will pick up enough satellites to get a reading). If the satellite positions are favorable, your accuracy gets better. I would like to GPS every sprinkler and iso valve on the property. I need to make an investment in some form of GPS unit first. I am leaning toward a receiver for my smart phone vs a standalone unit. Collecting the data via smart phone or pda means I can save the raw data and use some of the computer models out there to use enhanced geometry to make that data more accurate

[Kiril]

I am leaning toward a receiver for my smart phone vs a standalone unit.

This is also an option I was looking at. Considerably cheaper than an all-in-one unit. Even the sub-foot units require some post processing in order to really hone in the positioning. I have a openGIS workstation right now, just need a decent means of collecting accurate data.

These were the units I was looking at for the type of solution you are thinking.

https://buy.garmin.com/shop/shop.do?cID=158

[bicmudpuppy]

Its probably the cowards way out, but I've been watching ebay off and on. Not as accurate as I really want to be, but there are some amazing bargains in the bluetooth for pda GPS units. You can get into a 3M unit for under $50, but your going to have to hunt for the software. There are some neat looking apps out there that are third party stuff. A lot of them shareware/freeware too.

[Kiril]

There are some neat looking apps out there that are third party stuff. A lot of them shareware/freeware too.

Here's the Linux way to build a GIS workstation using Ubuntu.

http://www.perrygeo.net/wordpress/?p=10

[Kiril]

A maintained list of open source GIS related software.

http://opensourcegis.org/

[ARGOS]

Outside my scope of work, but really cool stuff. It would be handy for as-builts.

[Waterit]

Outside my scope of work, but really cool stuff. It would be handy for as-builts.

What's an as-built, Obi-Wan?

[ARGOS]

As-built drawings are produced by the contractor and compared with the original design documents to identify any changes made during installation that could affect the system's performance. Discrepancies between the original bid-set drawings and the installation must be corrected prior to system start-up and use. Problems can be as minor as an incorrectly marked pipe or as major as a motor supplied with the wrong voltage. Ideally, the "as-built" verification is performed several times during construction, so that conflicts between design and installation can be resolved with minimal effect on the project schedule.

ctrl c and ctrl v is a wonder.

[Waterit]

As-built drawings are produced by the contractor and compared with the original design documents to identify any changes made during installation that could affect the system's performance. Discrepancies between the original bid-set drawings and the installation must be corrected prior to system start-up and use. Problems can be as minor as an incorrectly marked pipe or as major as a motor supplied with the wrong voltage. Ideally, the "as-built" verification is performed several times during construction, so that conflicts between design and installation can be resolved with minimal effect on the project schedule.

Holy cow, it was a joke!

[ARGOS]

I know. Ditto.

[Wet_Boots]

Like anyone ever consults the drawings......

[ARGOS]

Like anyone ever consults the drawings......

Only when it's already too late.

[TRILAWNCARE]

And what are you supposed to do with As-built drawings? Anyone.

[Wet_Boots]

And what are you supposed to do with As-built drawings? Anyone.Break the sprinklers as usual, and claim they weren't located where the drawing showed.

[Waterit]

And what are you supposed to do with As-built drawings? Anyone.

Before or after the customer spends hours searching for them?

[Mike Leary]

I made three copies; one for the client, copy at clock, ditto for files; me and Russ fished many a time to find ours in the files 'cause the rest had disappeared!

[FIMCO-MEISTER]

Break the sprinklers as usual, and claim they weren't located where the drawing showed.

here is a plan for a job I looked at while hanging out with JW Jr. Each head is coded.

[Mike Leary]

Designs: they never work. Those don't. :dizzy:

[FIMCO-MEISTER]

Designs: they never work. Those don't. :dizzy:

This system was already in. I like that a service guy can notate specific heads and put that in his work orders to explain to whoever what got done and where.

[Mike Leary]

You forget what liars we installers are.

[TRILAWNCARE]

Your supposed to give the As-built plans to the architect, engineer, ect so a accurate plan of the install can be made called a Record Drawings. Who has ever done that?

Ever run across this Mike. http://www.redmond.gov/insidecityhall/publicworks/pdfscivils/RecordDrawing.pdf

Hope you had a good time camping.

[Kiril]

Is no topic sacred? Geez, I have to wade through 100 posts just to find 3 that are on-topic. **** :rolleyes::rolleyes::rolleyes::rolleyes:

[FIMCO-MEISTER]

You forget what liars we installers are.

The installer didn't do that one. It was drawn up many years later by somebody else and was accurate.

[ARGOS]

Your supposed to give the As-built plans to the architect, engineer, ect so a accurate plan of the install can be made called a Record Drawings. Who has ever done that?

Sorry Kiril, but...

I've had the building department request them several times. As-built plans should be given to any designer/LA as well. As Mike mentioned I keep an as-built plan in my files. I have made the mistake of trying to work off originals because I didn't make an as-built. I tossed the original aside and tried to rack my memory.

[Mike Leary]

I've been away, what was the topic?

[DanaMac]

I've been away, what was the topic?

Nothing you'd be interested in. Go back to the camping and wine drinking. It's more fun. :)

[ARGOS]

I've been away, what was the topic?

Is that you driving?

[Waterit]

Your supposed to give the As-built plans to the architect, engineer, ect so a accurate plan of the install can be made called a Record Drawings. Who has ever done that?

So that they can prmoptly file them away and/or lose them. The few times I've needed as-builts (other than my own) they were unavailable, meaning lost.

I've done as-builts a few times when working on Navy or Air Force base, and some municipal jobs. If you don't turn them in, you don't get paid. payup

[ARGOS]

Geez Waterit the kids are in the room.

[DanaMac]

Water It - is that Gator Bait? - or Jail Bait?

[TRILAWNCARE]

Boots must be on lock down, or he would spoil our viewing pleasure.

[DanaMac]

Boots must be on lock down, or he would spoil our viewing pleasure.

He's at rec time in the yard. Hittin' the weights.

[Kiril]

Hey mods, we need a B.S. filter for the irrigation forum.

[Waterit]

Water It - is that Gator Bait? - or Jail Bait?

Gator Bait, straight from the U of Florida.

Want some more?

And no we don't need BS detectors, we pretty much take for granted that most here are full of hot air:

130620

[FIMCO-MEISTER]

Okay Kiril I read it, looked at the units and will try to get back on topic. What are your specific usages besides valve marking? I'm assuming to send soil and moisture data to create maps?

[Dripit good]

here is a plan for a job I looked at while hanging out with JW Jr. Each head is coded.

Do they each have nicknames to go along with their formal ones?

[Waterit]

The sprays are "Felix" and the rotors "Oscar". The bubblers are affectionately known as "Joe".

[FIMCO-MEISTER]

Do they each have nicknames to go along with their formal ones?

Being lazy. John Wingfield Jr.

[Kiril]

Okay Kiril I read it, looked at the units and will try to get back on topic. What are your specific usages besides valve marking? I'm assuming to send soil and moisture data to create maps?

To list a few.

- Perform spatial analysis of different soil properties (water, Ec, nutrient, compaction, etc...).

- Marking sample sites in order to return to the same spot for comparative reasons (i.e. quantify the effectiveness of your management program)

- Evaluate sprinkler/nozzle performance

[ICS]

I have a TDS Recon that I bought a year ago and never used. Battery holds a charge. Anyone interested send a PM