I had the pleasure of working with the foremost surveyor in my community on a few occasions.
He is actually "the surveyor" that businesses & government bring in to fix/correct inaccurate surveys.
In my case, I am not versed in surveying techniques, but I do have the basics pretty well figured out. I have been out capturing x,y,z data for the purposes of watershed analysis, and I've also been out in the field capturing data from test pits and drill collars for the purposes of Hydrogeological studies.
First off, the Geodetic equipment "does" report your accuracy values, so if you're getting sub-centimetre feedback while in the field, you should be just fine. As far as your question regarding "good tips", the most important information that the surveyor mentioned to me was as follows:
- Find a nice open area for your base station, BUT, also look for an area that will shelter your equipment from the possibility of theft.
What he did, is start at a known benchmark (an IB), then he moved his receiving station to an arbitrary location that provided good communication with the satelites, but was also "not" visible to passers-by. You would be surprised what people will steal (even if they don't know what it is, if it looks like it might be worth some money ....).
Watch your weather as part of you planning process. Heavy cloud cover can really throw a monkey wrench in to your day.
He also told me these units don't like evergreen trees. Try to stay away from an area heavily forested with conifers if you can.
If you're shooting in a dense forest that is mostly coniferous, you'll need the backpack unit and antenna. His unit however, is about 3-years-old.
That said, this may no longer be an issue with the newer units (just telling you what he shared with me).
- This one is important!! He said when you're going to be conducting field survey for multiple days, always try to pinpoint something permanent as a location for your base station.
If you're signal starts getting weak, it might be time to plant a rod somewhere (ex - at the top of a bedrock outcrop) or to find another survey monument to move to.
He stressed the importance of this one!! He said, "even if I have to come back 2 years from now, I can be rest assured that I have plenty of survey benchmarks to utilize if need be".
What this accomplishes, is that you have a "known" that is easy-to-locate/return to, that is nicely situated (reception, protected from theft), and relatively permanent. This school of thought ALSO shaves huge amounts time off of the set up process the next day, next week, a year later .....
- Lastly, have an axe (if you're in remote/forested areas), lots of batteries, etc, etc. In short, be prepared.
I am envious!! That's a nice toy. Hope these suggestions are helpful, and have fun!!
Best Answer
This is all just my opinion but here are my 2cents worth, but yes you are on the right track.
It really depends on the asset type you are capturing for a start and what kind of information you are planning to collect, and how much time you have to train people etc. Generally I prefer the PDA route as it allows faster information processing and cuts the middle man out in a effort to remove the chance of mistakes in data entry.
The PDA route is not a bad option and it's a shame that you hitting heavy criticism with it but it happens I guess.
If you are on a WM and MapInfo there is GBMMobile which you can use the inbuilt/external GPS to capture points and it will also handle using the onboard camera and attach the photo to the point for you.
There is also a open source PDA program: http://www.gvsig.org/web/projects/gvsig-mobile/tour/image-gallery/ but I have never used it so I can't tell you how good it is.
The biggest problem we have had is finding good and stable PDAs with GPS and Cameras, you can buy rugged ones but they range about $1500-$3000+.
Depending on the asset type we have taken a few different tactics, this is due to having a small GIS/Asset team.
We have both PDAs and a GPS enabled camera, for simple assets we tend to use the GPS enabled camera. We get someone to go out and take photos of the assets, I then strip out the GPS coordinates with a MapInfo based program I wrote, I then have a piece of software that someone in the office can sit down and go though the photos and give the point some more data eg Asset Type, Condition. Of course this only works for really simple assets that don't really require measurements (play eq, park seats, bins are a good for this).
The second way is to use a PDA with GBMMobile to capture the asset and fill out the information out in the field, for more detailed stuff.
The third way is to capture the points with GPS, give them a asset number and then print out a map and some forms to capture the information and give it to a field crew. We use this option to capture inverts and manhole conditions for our sewer network. We use paper here because we couldn't find any software that really did what we needed(well) and the crews work on and off this project and the last thing they need to be worried about is a electronic device stuffing up in the middle of a job.
Pros:
Cons:
My general advice is it is a good way to go, but start small and grow out. Don't try and roll a heap of them out to field crew straight away or you will have more resistance and non-compliance, then you will have no data at all.