GIS for surveyors: Seeking advice about organizing field data

[Anonymous]

We are a small surveying office. We would like to integrate our survey
boundary lines and monuments into a common GIS system. We have data from
field books, conventional surveys, GPS surveys and Autocad drawings. This
data for the most part must be transformed from arbitrary coordinates to a
common map projection. We work in US feet and must be able to work in ground
and grid coordinates. I have no formal training in GIS or surveying, but
have extensive experience in the field and office and have learned a bit
about
projections and mapping on my own.

I would like to get suggestions on reference materials that would guide me
in setting up the GIS. I will need guidance about what projection would be
most versatile, pitfalls to avoid, handling discrepencies in data, etc.

We are using Autocad Map 5.0, Land Desktop 3, Trimble Geomatics 1.5

Thank you

[Anonymous]

Hi Neil,

The first thing I would ask is why do you want to integrate your data? How
are you planning on using the data; is it for a county GIS or a survey
database? Is the information from the same survey area or a series in the
same county or state? Do you have information in external databases that you
want to integrate? Do you want to work with existing data, such as TIGER
files, as well as your data? Putting all the files together can be a lot of
work to manage. Do you have standards in place, or is the data likely to
have blocks with the same name but different geometry and shapes? How much
data do you have?

With Map, you can work with data in different coordinate systems, even
though it can slow things down a little.

I would recommend some training in the GIS area before you start a major
project, or try a pilot project on a small chunk of data to see what is
involved. Before you start such a project, think about what the goals of
integrating your data is, what the expected end result is, your budget (!),
and so on.

There is some help in the Map online manuals about organizing your data.

In terms of data organization, I would recommend looking at a series of
articles on autodesk's PointA site: http://pointa.autodesk.com by Will
Crichton on organizing your data.

There are two books on the market for AutoCAD Map:
Inside AutoCAD Map 2000 by Dylan Vance Ray Eisenberg David Walsh
and
Using AutoCAD Map 2000 by Mark Oliver

Feel free to ask more questions though!

Cheers,
David Walsh
Autodesk Map Product Designer

"Neil Wilson" wrote in message
news:5F3913B26B3879C73A07319890371406@in.WebX.maYIadrTaRb...
> We are a small surveying office. We would like to integrate our survey
> boundary lines and monuments into a common GIS system. We have data from
> field books, conventional surveys, GPS surveys and Autocad drawings. This
> data for the most part must be transformed from arbitrary coordinates to a
> common map projection. We work in US feet and must be able to work in
ground
> and grid coordinates. I have no formal training in GIS or surveying, but
> have extensive experience in the field and office and have learned a bit
> about
> projections and mapping on my own.
>
> I would like to get suggestions on reference materials that would guide me
> in setting up the GIS. I will need guidance about what projection would be
> most versatile, pitfalls to avoid, handling discrepencies in data, etc.
>
> We are using Autocad Map 5.0, Land Desktop 3, Trimble Geomatics 1.5
>
> Thank you
>
>
>

[Anonymous]

Hi Neil,

As suggested by David, the road to a complete GIS-like organization of your data is quite long and depending on the nature, source and character of the different data sets that you have, one needs to study, evaluate possibilities and work out efficient data flow and management techniques.

Rather than take on the entire challenge of GIS'ing your work, I would advise you to take on the challenge in bits and pieces. The first thing that you can do (and I have seen many survey offices still not doing it) is to make it a point to store all your attributes in a object tables or better still as externally linked database tables. This would be the first step in creating what would be correctly formed GIS data. Never ever store your attribute data as plain text or block attribute etc.

The next step would be to ensure that correct geometry is created. Try and detect errors in geometry like closing errors, badly snapped lines and points and make sure they are correct. There are enough tools in Map / LDDT to ensure that this can be done. Having a clean data set - both geometric and attributes is the first requisite for any meaningful GIS implementation.

Once these are in place, you can now take on the other challenges to improve your process flow and enable GIS-queries to be built so that you can get more out of your system.

It is not difficult - it just needs proper thinking, organization and a discipned approach that should be followed by one and all in your organization.

Feel free to ask me for any advise.

Rakesh Rao
Autodesk Map Consultant & programmer
Four Dimension Technologies
www.4d-technologies.com

[Anonymous]

Thank you both for your extensive replies. My
vision of this project is to have a database of surveyed monuments with
established lat/longs and coordinates. Each monument will be a block with
attributes linked to an external database which will provide additional details.
The challenge that I anticipate will be to reconcile variations in measurements
of locations and what to do if an error is discovered that requires everything
to be adjusted. Maintaining a track record would be imperitive as well as
rectifying the changes in all surveys that are affected by the changes.
Additionally, since most of our legacy data is available on paper only and using
ground based arbitrary coordinate systems, there would be a considerable amount
of work in transforming each one to a known projection. Thus the question
arises, should we use a ground based system? If so then what happens when it
extends over a large area? Too, we would need to be able to project the data to
known projections in order to integrate with other existing data. Starting
out on a small scale certainly would be wise, but even so, it would be helpful
to have a clear view of the issues and problems in advance. That is the reason
for my post.

I'll continue to watch for additional suggestions.
Your advice is very much appreciated.

"rakesh.rao" <
href="mailto:rakesh.rao@4d-technologies.com">rakesh.rao@4d-technologies.com>
wrote in message
href="news:f0b4100.1@WebX.maYIadrTaRb">news:f0b4100.1@WebX.maYIadrTaRb...

style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">

Hi Neil,

As suggested by David, the road to a complete GIS-like organization of your
data is quite long and depending on the nature, source and character of the
different data sets that you have, one needs to study, evaluate possibilities
and work out efficient data flow and management techniques.

Rather than take on the entire challenge of GIS'ing your work, I would
advise you to take on the challenge in bits and pieces. The first thing that
you can do (and I have seen many survey offices still not doing it) is to make
it a point to store all your attributes in a object tables or better still as
externally linked database tables. This would be the first step in creating
what would be correctly formed GIS data. Never ever store your attribute data
as plain text or block attribute etc.

The next step would be to ensure that correct geometry is created. Try and
detect errors in geometry like closing errors, badly snapped lines and points
and make sure they are correct. There are enough tools in Map / LDDT to ensure
that this can be done. Having a clean data set - both geometric and attributes
is the first requisite for any meaningful GIS implementation.

Once these are in place, you can now take on the other challenges to
improve your process flow and enable GIS-queries to be built so that you can
get more out of your system.

It is not difficult - it just needs proper thinking, organization and a
discipned approach that should be followed by one and all in your
organization.

Feel free to ask me for any advise.

Rakesh Rao
Autodesk Map Consultant & programmer
Four Dimension
Technologies
www.4d-technologies.com

[pford]

From what I saw of your second posting, it looks like database design is going to be one of the most important elements in your project. I would like to recommend a couple of resouces for information on database models. One would be the database standard developed by the Wisconsin Land Infomation Association (WLIA) that is available at http://www.wlia.org/standards.html. The second resource would be the database model developed for the Federal Geographic Data Committee by Dr Nancy von Meyer (a Wisconsin RLS). I had a draft copy of the model and it addressed most if not all your concerns and issues. I have not seen the final version and don't know where on the Fed's site it would be. If you can't find it Nancy's e-mail address is: nancy@fairview-industries.com

Pat Ford