Trimble Business Center

Hello, I'm looking for some insight as to how TBC and trimble access apply the ground scale factor that I input. I started a job in NAD83 2011 adjustment with a ground scale factor of 1.0001485221 entered. If I take this scale factor x my grid base point coordinates I should come up with: 

421,173.7664 N * 1.0001485221 = 421,236.3200 N
1,889,225.8327 E * 1.0001485221 = 1,889,506.4245 E

But, when trimble access or TBC transform my base point with the entered scale factor I get:
421235.811 N
1889214.274

Any idea as to how its calculating those numbers? I'd like to be able to set up jobs with just the coordinate system and scale factor but if its not transforming the data correctly I might have to set up a different template.

------------------------------
Tyler Bohl
------------------------------

Projection Scale Factors are applied to LENGHTS not COORDINATES.
What you're referring to is is SCALE for HELMERT TRANSORMATION with ORIGIN at (0,0).
This is not how projections work, they do not use helmet transformations.

I don't quite understand what you mean by just the coordinate system and scale factor.
Do you want to use Published Coordinate System or do you want to define custom Local Coordinate System (Local Site in TBC)?

------------------------------
Marian
------------------------------

Original Message:
Sent: 12-15-2022 10:50
From: Tyler Bohl
Subject: TBC not applying Ground Scale Factor correctly

Hello, I'm looking for some insight as to how TBC and trimble access apply the ground scale factor that I input. I started a job in NAD83 2011 adjustment with a ground scale factor of 1.0001485221 entered. If I take this scale factor x my grid base point coordinates I should come up with: 

421,173.7664 N * 1.0001485221 = 421,236.3200 N
1,889,225.8327 E * 1.0001485221 = 1,889,506.4245 E

But, when trimble access or TBC transform my base point with the entered scale factor I get:
421235.811 N
1889214.274

Any idea as to how its calculating those numbers? I'd like to be able to set up jobs with just the coordinate system and scale factor but if its not transforming the data correctly I might have to set up a different template.

------------------------------
Tyler Bohl
------------------------------

I'm using a published state plane system with a ground scale factor applied. When setting up my job I pick the relevant coordinate system and zone for where I am working, and then I refer to our states DOT handbook to find the appropriate ground scale factor for where I am. Here is what it says in the handbook:

Distance example:
A project is located in Burleigh County. The Burleigh County conversion factor (cf) is 0.9998515. The 1/cf factor is
1.0001485221.
1. To determine the ground distance from the grid distance, divide the grid distance by the conversion factor.
The distance on the grid is 5279.22 feet.
What is the ground distance?
5279.22 / 0.9998515 = 5280 feet
The ground distance is 5280 feet.
2. To determine the grid distance from a ground distance, multiply the ground distance by the conversion factor.
The distance on the ground is 5280 feet.
What is the grid distance?
5280 * 0.9998515 = 5279.22 feet
The grid distance is 5279.22 feet
NOTE: One (1) divided by the conversion factor will provide a ground factor that when multiplied by the grid
distances will determine the ground distances.
5279.22 * 1.0001485221 = 5280 feet
_________________________________________________________________________________________
Coordinate example:
A project is located in Burleigh County. It has the same conversion factors as the example above.
1. To determine the ground coordinates (DOT Burleigh County Coordinate System) from the grid coordinates.
Multiply the grid coordinates by 1.0001485221.
Grid Coordinates * Burleigh County conversion factor (1/cf) = Ground coordinate
421,173.7664 N * 1.0001485221 = 421,236.3200 Y
1,889,225.8327 E * 1.0001485221 = 1,889,506.4245 X
2. To determine the grid coordinate (State Plane coordinate) from the ground coordinates.
Multiply the ground coordinates by 0.9998515.
Ground coordinate * Burleigh County conversion factor (cf) = Grid coordinate (state plane-South Zone)
421,236.3200 Y * 0.9998515 = 421,173.7664 N
1,889,506.4245 X * 0.9998515 = 1,889,225.8328 E
It is always a good idea to hand calculate the conversions back and forth for at least one GPS control point, then
compare those values with what is given from the GPS processing software normally used. This will insure the
correct local site settings are properly entered.

Is this the correct way of doing it or is our DOT wrong?

------------------------------
Tyler Bohl
------------------------------

Original Message:
Sent: 12-15-2022 14:33
From: Marian Plucinski
Subject: TBC not applying Ground Scale Factor correctly

Projection Scale Factors are applied to LENGHTS not COORDINATES.
What you're referring to is is SCALE for HELMERT TRANSORMATION with ORIGIN at (0,0).
This is not how projections work, they do not use helmet transformations.

I don't quite understand what you mean by just the coordinate system and scale factor.
Do you want to use Published Coordinate System or do you want to define custom Local Coordinate System (Local Site in TBC)?

------------------------------
Marian

Original Message:
Sent: 12-15-2022 10:50
From: Tyler Bohl
Subject: TBC not applying Ground Scale Factor correctly

Hello, I'm looking for some insight as to how TBC and trimble access apply the ground scale factor that I input. I started a job in NAD83 2011 adjustment with a ground scale factor of 1.0001485221 entered. If I take this scale factor x my grid base point coordinates I should come up with: 

421,173.7664 N * 1.0001485221 = 421,236.3200 N
1,889,225.8327 E * 1.0001485221 = 1,889,506.4245 E

But, when trimble access or TBC transform my base point with the entered scale factor I get:
421235.811 N
1889214.274

Any idea as to how its calculating those numbers? I'd like to be able to set up jobs with just the coordinate system and scale factor but if its not transforming the data correctly I might have to set up a different template.

------------------------------
Tyler Bohl
------------------------------

I've just downloaded https://www.dot.nd.gov/manuals/design/surveymanual/19_1surveys/PRT1_CHAPTER_19.pdf

Seems to me like NAD83 is based on Lambert Conical Projection.

I 100% agree with Distance Example. That exactly how it's done.

Now, for the second part:

1) I have never ever run in my life into "Ground Coordinates" There are Ground and Grid Distances.
2) I do understand that there is a need of Coordinate System where Ground Distance = Grid distance, e.g. bridge works or cadastral, but that usually fixed by creating Local Site or defining your own custom projection.
3) The scale factor you are using (0.9998515) is combined scale factor, which is a function of projection scale factor and elevation scale factor but for the POINT only.
4) Your 0,0 point is somewhere in Montana (1,935,600 ft to the West)
5) By multiplying your coordinate values by the scale factor all your doing is calculating "ground distance" from that 0,0 point in Montana, but assuming that the Projection Scale factor doesn't change along the way (which is does) and that elevation doesn't change along the way (which is does)
6) I'll be honest, I fail to see any application of the "Coordinate Example" from the manual above, unless your building 400 mile long highway from Montana to ND and you want its length on the plan to match exactly the length on the ground.







------------------------------
Marian
------------------------------

Original Message:
Sent: 12-15-2022 14:45
From: Tyler Bohl
Subject: TBC not applying Ground Scale Factor correctly

I'm using a published state plane system with a ground scale factor applied. When setting up my job I pick the relevant coordinate system and zone for where I am working, and then I refer to our states DOT handbook to find the appropriate ground scale factor for where I am. Here is what it says in the handbook:

Distance example:
A project is located in Burleigh County. The Burleigh County conversion factor (cf) is 0.9998515. The 1/cf factor is
1.0001485221.
1. To determine the ground distance from the grid distance, divide the grid distance by the conversion factor.
The distance on the grid is 5279.22 feet.
What is the ground distance?
5279.22 / 0.9998515 = 5280 feet
The ground distance is 5280 feet.
2. To determine the grid distance from a ground distance, multiply the ground distance by the conversion factor.
The distance on the ground is 5280 feet.
What is the grid distance?
5280 * 0.9998515 = 5279.22 feet
The grid distance is 5279.22 feet
NOTE: One (1) divided by the conversion factor will provide a ground factor that when multiplied by the grid
distances will determine the ground distances.
5279.22 * 1.0001485221 = 5280 feet
_________________________________________________________________________________________
Coordinate example:
A project is located in Burleigh County. It has the same conversion factors as the example above.
1. To determine the ground coordinates (DOT Burleigh County Coordinate System) from the grid coordinates.
Multiply the grid coordinates by 1.0001485221.
Grid Coordinates * Burleigh County conversion factor (1/cf) = Ground coordinate
421,173.7664 N * 1.0001485221 = 421,236.3200 Y
1,889,225.8327 E * 1.0001485221 = 1,889,506.4245 X
2. To determine the grid coordinate (State Plane coordinate) from the ground coordinates.
Multiply the ground coordinates by 0.9998515.
Ground coordinate * Burleigh County conversion factor (cf) = Grid coordinate (state plane-South Zone)
421,236.3200 Y * 0.9998515 = 421,173.7664 N
1,889,506.4245 X * 0.9998515 = 1,889,225.8328 E
It is always a good idea to hand calculate the conversions back and forth for at least one GPS control point, then
compare those values with what is given from the GPS processing software normally used. This will insure the
correct local site settings are properly entered.

Is this the correct way of doing it or is our DOT wrong?

------------------------------
Tyler Bohl

Original Message:
Sent: 12-15-2022 14:33
From: Marian Plucinski
Subject: TBC not applying Ground Scale Factor correctly

Projection Scale Factors are applied to LENGHTS not COORDINATES.
What you're referring to is is SCALE for HELMERT TRANSORMATION with ORIGIN at (0,0).
This is not how projections work, they do not use helmet transformations.

I don't quite understand what you mean by just the coordinate system and scale factor.
Do you want to use Published Coordinate System or do you want to define custom Local Coordinate System (Local Site in TBC)?

------------------------------
Marian

Original Message:
Sent: 12-15-2022 10:50
From: Tyler Bohl
Subject: TBC not applying Ground Scale Factor correctly

Hello, I'm looking for some insight as to how TBC and trimble access apply the ground scale factor that I input. I started a job in NAD83 2011 adjustment with a ground scale factor of 1.0001485221 entered. If I take this scale factor x my grid base point coordinates I should come up with: 

421,173.7664 N * 1.0001485221 = 421,236.3200 N
1,889,225.8327 E * 1.0001485221 = 1,889,506.4245 E

But, when trimble access or TBC transform my base point with the entered scale factor I get:
421235.811 N
1889214.274

Any idea as to how its calculating those numbers? I'd like to be able to set up jobs with just the coordinate system and scale factor but if its not transforming the data correctly I might have to set up a different template.

------------------------------
Tyler Bohl
------------------------------

This is entirely doable and all our jobs follow a similar procedure. In TBC you use the "Local Site" function in the Survey tab, set the "project location" to N0 E0, put a project elevation, enter your combined scale factor (note: all Trimble products I'm aware of use the GRID to GROUND number where DOT's and NGS often publish the GROUND to GRID number).

------------------------------
Andrew Haukås
------------------------------

Original Message:
Sent: 12-15-2022 10:50
From: Tyler Bohl
Subject: TBC not applying Ground Scale Factor correctly

Hello, I'm looking for some insight as to how TBC and trimble access apply the ground scale factor that I input. I started a job in NAD83 2011 adjustment with a ground scale factor of 1.0001485221 entered. If I take this scale factor x my grid base point coordinates I should come up with: 

421,173.7664 N * 1.0001485221 = 421,236.3200 N
1,889,225.8327 E * 1.0001485221 = 1,889,506.4245 E

But, when trimble access or TBC transform my base point with the entered scale factor I get:
421235.811 N
1889214.274

Any idea as to how its calculating those numbers? I'd like to be able to set up jobs with just the coordinate system and scale factor but if its not transforming the data correctly I might have to set up a different template.

------------------------------
Tyler Bohl
------------------------------

I work in Oregon and had the same issue.  I did my work and exported the coordinate list to Civil 3D but when I listed the Lat and Long in Civil 3D I did not get the same as TBC or Access was giving me.

I figured out that Trimble does not scale around 0,0 but rather the center meridian of the state plane zone.  This is taken care of by entering a false easting into in TBC or Access.  For Oregon North the false easting is calculated as   -1.0*(scalefactor - 1.00)*Eo.   Eo being the false easting of the zone (see attached for Oregon).  For Oregon North Eo = 2500000m.  If I have a scale factor of 1.00012345 then my false easting I enter into Trimble is -1.0*(1.00012345-1)*2500000m=-308.625m or -1012.549ift.  The state plane false northing or "No" is usually 0.00 for most states so you do not need to calculate a false northing for Trimble.   When I set up my AutoCAD drawings with a state plane coordinate system and a scale factor then everything makes sense.  In AutoCAD the scale factor is 1/x of the trimble scale factor.

------------------------------
Kaid McKay
------------------------------

Original Message:
Sent: 12-15-2022 10:50
From: Tyler Bohl
Subject: TBC not applying Ground Scale Factor correctly

Hello, I'm looking for some insight as to how TBC and trimble access apply the ground scale factor that I input. I started a job in NAD83 2011 adjustment with a ground scale factor of 1.0001485221 entered. If I take this scale factor x my grid base point coordinates I should come up with: 

421,173.7664 N * 1.0001485221 = 421,236.3200 N
1,889,225.8327 E * 1.0001485221 = 1,889,506.4245 E

But, when trimble access or TBC transform my base point with the entered scale factor I get:
421235.811 N
1889214.274

Any idea as to how its calculating those numbers? I'd like to be able to set up jobs with just the coordinate system and scale factor but if its not transforming the data correctly I might have to set up a different template.

------------------------------
Tyler Bohl
------------------------------

Kaid, Are you setting the Northing and Easting to 0 under the "Local Site" function in the Survey tab.  We work in WA and ID and use a grid scale factor in 90% of our work using this function and it always scales to 0,0.  

------------------------------
Mike Hathaway
------------------------------

Original Message:
Sent: 12-30-2023 02:33
From: Kaid McKay
Subject: TBC not applying Ground Scale Factor correctly

I work in Oregon and had the same issue.  I did my work and exported the coordinate list to Civil 3D but when I listed the Lat and Long in Civil 3D I did not get the same as TBC or Access was giving me.

I figured out that Trimble does not scale around 0,0 but rather the center meridian of the state plane zone.  This is taken care of by entering a false easting into in TBC or Access.  For Oregon North the false easting is calculated as   -1.0*(scalefactor - 1.00)*Eo.   Eo being the false easting of the zone (see attached for Oregon).  For Oregon North Eo = 2500000m.  If I have a scale factor of 1.00012345 then my false easting I enter into Trimble is -1.0*(1.00012345-1)*2500000m=-308.625m or -1012.549ift.  The state plane false northing or "No" is usually 0.00 for most states so you do not need to calculate a false northing for Trimble.   When I set up my AutoCAD drawings with a state plane coordinate system and a scale factor then everything makes sense.  In AutoCAD the scale factor is 1/x of the trimble scale factor.

------------------------------
Kaid McKay

Original Message:
Sent: 12-15-2022 10:50
From: Tyler Bohl
Subject: TBC not applying Ground Scale Factor correctly

Hello, I'm looking for some insight as to how TBC and trimble access apply the ground scale factor that I input. I started a job in NAD83 2011 adjustment with a ground scale factor of 1.0001485221 entered. If I take this scale factor x my grid base point coordinates I should come up with: 

421,173.7664 N * 1.0001485221 = 421,236.3200 N
1,889,225.8327 E * 1.0001485221 = 1,889,506.4245 E

But, when trimble access or TBC transform my base point with the entered scale factor I get:
421235.811 N
1889214.274

Any idea as to how its calculating those numbers? I'd like to be able to set up jobs with just the coordinate system and scale factor but if its not transforming the data correctly I might have to set up a different template.

------------------------------
Tyler Bohl
------------------------------

Original Message:
Sent: 1/3/2024 12:21:00 PM
From: Mike Hathaway
Subject: RE: TBC not applying Ground Scale Factor correctly

Kaid, Are you setting the Northing and Easting to 0 under the "Local Site" function in the Survey tab.  We work in WA and ID and use a grid scale factor in 90% of our work using this function and it always scales to 0,0.  

------------------------------
Mike Hathaway
------------------------------

Original Message:
Sent: 12-30-2023 02:33
From: Kaid McKay
Subject: TBC not applying Ground Scale Factor correctly

I work in Oregon and had the same issue.  I did my work and exported the coordinate list to Civil 3D but when I listed the Lat and Long in Civil 3D I did not get the same as TBC or Access was giving me.

I figured out that Trimble does not scale around 0,0 but rather the center meridian of the state plane zone.  This is taken care of by entering a false easting into in TBC or Access.  For Oregon North the false easting is calculated as   -1.0*(scalefactor - 1.00)*Eo.   Eo being the false easting of the zone (see attached for Oregon).  For Oregon North Eo = 2500000m.  If I have a scale factor of 1.00012345 then my false easting I enter into Trimble is -1.0*(1.00012345-1)*2500000m=-308.625m or -1012.549ift.  The state plane false northing or "No" is usually 0.00 for most states so you do not need to calculate a false northing for Trimble.   When I set up my AutoCAD drawings with a state plane coordinate system and a scale factor then everything makes sense.  In AutoCAD the scale factor is 1/x of the trimble scale factor.

------------------------------
Kaid McKay

Original Message:
Sent: 12-15-2022 10:50
From: Tyler Bohl
Subject: TBC not applying Ground Scale Factor correctly

Hello, I'm looking for some insight as to how TBC and trimble access apply the ground scale factor that I input. I started a job in NAD83 2011 adjustment with a ground scale factor of 1.0001485221 entered. If I take this scale factor x my grid base point coordinates I should come up with: 

421,173.7664 N * 1.0001485221 = 421,236.3200 N
1,889,225.8327 E * 1.0001485221 = 1,889,506.4245 E

But, when trimble access or TBC transform my base point with the entered scale factor I get:
421235.811 N
1889214.274

Any idea as to how its calculating those numbers? I'd like to be able to set up jobs with just the coordinate system and scale factor but if its not transforming the data correctly I might have to set up a different template.

------------------------------
Tyler Bohl
------------------------------