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How are boundaries resolved when using State Plane or other Geodetic coordinates. Say you wanted to use a bearing-bearing intersection to create a third position between two found monuments. Would you take a calculator out, apply the difference to the local map and rotate record? Are you first resolving with local bearings then rotating later? Least squared? What is the process?
- Posted by: James Flemingfadf
Monitoring 0%
We have a lot of GIS resources available to download and pretty robust RTN network(s). It makes sense to put all but the smallest urban boundaries in SPC to be able to bring in photos, aerial topo, etc.
I even like to use real world coordinates on our monitoring projects. I lets me easily add background information which the client may find useful.
- Posted by: Daniel Ralph
More than 75% of the work that I do starts at a local coordinate system, be it 3000/5000 or an extension of something that is previously recorded by me or others. For the type of boundary retracement that I do, there is usually no reason to introduce another bearing system to the mix. However, I am seeing a shift from using what I want to use as a coordinate system to being forced to use some other geopolitical system in order to accommodate someone who has no clue what it is that they are requiring.
Very well said and 100% true!
We had the wild west set up: 5000/5000, 2500/2500, 10000/10000…….. and any other combinations other than 0,0.
I was confused as hell at first, and then was told to just go along with the plan……
Helps when nearly all of the Surveyors save 2 or 3 were constantly cracking the whip over the drafters/project managers heads.
- Posted by: aliquot
“The remainder of my surveys are true mean geodetic with NAD83 Lat and Long.”
BLM cadastral work? I use a BLM fellows software he wrote called ‘gogo’ to do this type of work, but have little call for it under my present circumstances. I’d wager you know him.
Willy Does anyone set control points with a GPS? Then use that coordinate info established by the GPS and start survey using a Total Station?
We would do all of our topo’s with local 5000, 5000 then once we bought a GPS we will set control points. Take that info and punch it into the total station and start our survey, just local roads slated for reconstruction.
100% of our work is done on a local coordinates, which is intended to align our runways to cardinal directions. We do have a projection in Civil 3D to transform State Plane to our local coordinates (unfortunately it can only be written ground to grid in C3D). We’ve also written an EPSG projection to be incorporated into ArcGIS software. So while everything is done on a local coordinates, our coordinates are defined by State Plane.
1 out of 500 projects are on a local coordinate system. I cringe every time i need to revisit an old company project on a local system.
There is no reason not to be utilizing the state plane coordinate system(s). But then there is no reason to be constructing linework and symbology manually in your CAD system, yet many are still using those old, slow methods. There is so much free information available around the country which also uses the same system, or at least close enough to the same system to be worthwhile.
- Posted by: WA-ID Surveyor
There is no reason not to be utilizing the state plane coordinate system(s).
Well, there sort of is reason: that grid-to-ground nuisance that too many people don’t properly deal with and/or document the metadata so it is obvious how to follow them. I’ve even seen a plat that used SPC distances without noting the fact they weren’t ground distances. Local or LDP avoid that issue.
. - Posted by: Jim Frame
The remainder of my surveys are true mean geodetic with NAD83 Lat and Long.
What field and office software do you use that allows you to work directly in geographic coordinates?
Carlson and topsurv.
Do you use that only to record data, or for stakeout, too? (“East a thousand of a second!”)
- Posted by: Bill93Posted by: WA-ID Surveyor
There is no reason not to be utilizing the state plane coordinate system(s).
Well, there sort of is reason: that grid-to-ground nuisance that too many people don’t properly deal with and/or document the metadata so it is obvious how to follow them. I’ve even seen a plat that used SPC distances without noting the fact they weren’t ground distances. Local or LDP avoid that issue.
Yes, scale factors are one reason. Other reasons are the inherent inaccuracies (the 1:10000 thing), and the fact that you will never match older surveys or official federal surveys.
Really I just dont see the point in adding additional inaccuracies and complications. State plane was great when the computations had to be done by hand, but now that computers can handle geodetic calculations with the click of a mouse, not so much.
- Posted by: Jim Frame
Do you use that only to record data, or for stakeout, too? (“East a thousand of a second!”)
It’s the same as using state plane. East .02′ except it is geodetic east and the .02 doesnt need a scale factor. Although, much to the chagrin of my assistants, I prefer meters in the field.
- Posted by: Bill93Posted by: WA-ID Surveyor
There is no reason not to be utilizing the state plane coordinate system(s).
Well, there sort of is reason: that grid-to-ground nuisance that too many people don’t properly deal with and/or document the metadata so it is obvious how to follow them. I’ve even seen a plat that used SPC distances without noting the fact they weren’t ground distances. Local or LDP avoid that issue.
I should clarify. When i said use I did not mean to infer that our final work products are all done on state plane coordinates. Our projects are all completed on grid but then we introduce a scale factor to convert to ground coordinates before any actual work product is completed. We are up to high in elevation and our scale factors are so great we cannot complete projects solely on grid.
And you are correct, without crisp clear documentation of your scale factors and how they relate to each project(when reporting coordinates) the information can be more than useless. Our system is
foolproofalmost foolproof! - Posted by: WA-ID SurveyorOur system is
foolproofalmost foolproof!It is probable that you have underestimated the ingenuity of fools.
Virtually all my surveys are local (50000, 50000) with ground distances and geodetic bearings (which are very close to astronomic). Most surveys I retrace were originally done with astronomic bearings and ground distances. The problem with state plane is that it is a mapping projection (flat) representing a curved surface (the earth) additionally the bearings are grid and the deflection from geodetic can be quite a bit.
I use gps for virtually everything with two static base stations and one rover, if I wish to convert to state plane at a later date, no problem. Actually I should be calculating in lat, long (geographic coordinates).
In Hawaii everything is on a local coordinate system.
How do you resolve boundaries while calling North something different than the original survey being retraced?
Been local horizontal control for the vast majority of boundary topo surveying I have done in the greater Seattle area, with the exception of fulfilling a municipal requirement or working on large sites.
I have never worked at a shop where GPS equipment went into the truck everyday.
90% of our work is local coordinates, GPS doesn’t work too well in Manhattan. Outside of transportation related projects, most projects end up being translated to put a 0,0 coordinate at one of the property corners with the entire site rotated to align with the street grid. The 0,0 is typically chosen by the architect during the design process. Most of the time they pick the south-west corner but architects being architects, I’ve seen just about every variation you can imagine, other corners resulting in negative coordinates, flipping 90 or 180 off of north just to keep the street at the bottom of the plans, not actually at the property corner but at some arbitrary offset from the corner, in the MIDDLE of the site, etc.
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