Topic: SCALE FACTORS

[Dent Cermak]

I have a new project that I want to do in LDD3. I'm really trying to get away from R14, but AutoDesk makes it SO hard!! Here's the deal. Project is set up on State Plane Coordinates by GPS observation. I wish to apply the "scale factor" to the field book data. I  have added the appropriate scale factor in my field book setting. Now in R14 you went to SURVEY PROTOTYPE SETTINGS then down to OBSERVATIONS then down to CORRECTIONS then checked the box next to SCALE FACTOR and all was right with the world. That would toggle the setting when I created the project based on the prototype.
How do I do that in LDD3, or higher?? I cannot find the "observation" settings. The SET PROTOTYPE SETTINGS no longer offers "observation corrections" as an option.
What am i missing here??





OK, so nobody knows what a scale factor is.  I still need to know how to set it up!

[Dinosaur]

I searched my 2005 help and was directed to "Changing the Geodetic Zone Transformation Settings".  I think this is what you are looking for at least in 2005 (no clue about LDD3), but a bit involved to post unless you can't get to it for some reason.  If you can't find it let me know and I will zip up a copy for you.  Now, if you were just using Civil 3D . . .

[Dent Cermak]

This is on the right track!! I set my SPC in the drawing setup and then went to the Transformation Settings and checked the user specified bubble and entered the scale factor I have. Coordinates are the same as before. Changed the scale factor in the field book, Coordinates are the same.
No matter what I set, the coordinates stay the same. There's one step I am missisng. Any further ideas??? 

[Dinosaur]

Did you do this part?

In addition to setting scale factors, you must also specify reference points. These reference points are the two points that tie the local and grid coordinates together. The reference points can be defined in two ways:

By the grid and local coordinates of two known reference points in your drawing.
By the grid and local coordinates of one known point and a known rotation to grid north.

[Mark]

This is what I found in the docs

To change the transformation settings

Select the current zone for the drawing. For more information, see Changing the Current Zone for a Drawing.
From the Projects menu, choose Transformation Settings to display the Transformation Settings dialog box.
The description of the current zone is displayed at the top of the dialog box.

Select the Apply Transform Settings check box. When this box is selected, the other settings in the dialog box become active.
Select the Apply Sea Level Scale Factor check box.
TIP  If you know the combined scale factor, then you can clear the Apply Sea Level Scale Factor check box, select User Specified as the Grid Scale Factor, and type a combined scale factor in the Grid Scale Factor box. The combined scale factor is the combination of the scale factor for converting local to sea level and the scale factor for converting sea level to grid.

Type a Default Elevation, such as the average elevation of your project site from sea level.
You can change the Spheroid Radius. The Spheroid Radius is the radius of a mathematical figure close to the shape of the Earth at sea level, approximately 6,370 km. The value shown in this box is initially derived from the current zone's ellipsoid and can be changed if local observations differ. In most cases, the default value shown is the accepted value.
Select one of the following Grid Scale Factor options:
Unity: To set the grid scale factor to 1.00 for all points within the zone.
User Specified: To activate the Grid Scale Factor box, where you can type the grid scale factor value. For example, you can type the average scale factor of the points in your survey. This value is used for all points or locations within the zone and is constant.
NOTE  If you specify a User Specified grid scale factor and then clear the Apply Transform Settings check box, the scale factor is still used in Autodesk Survey calculations. If the Scale Factor check box is selected in the Survey Correction Settings dialog box, then this scale factor is applied to all horizontal distances in Survey measurement calculations. For example, if you specify a horizontal distance of 500 feet to a sideshot point using the Survey Sideshot Instructional method, and the Scale Factor check box is selected and the scale factor value is set to 0.5, then the horizontal distance to the sideshot point will be 250 feet. The Survey Command Language command SF (SCALEFACTOR) always overrides the value specified for the scale factor in the Transformation Settings dialog box.

Reference Point: To use the scale factor of the specified reference point (see the following equation) as the grid scale factor for all points or locations within the zone.
Prismoidal Formula: To use the prismoidal formula to calculate the grid scale factor. This is the recommended method because it accounts for the fact that every point has a different scale factor.
IMPORTANT  When you use the Attach drawings feature of AutoCAD Map and you bring a source drawing that is set up in a different zone into the Map project, the source drawing is converted to the zone of the Map project. The Prismoidal Formula option sets a different value for each point within the zone. However, when you bring a source drawing that uses the Prismoidal Formula option into a Map project, a fixed scale factor is used. Therefore, the points that are brought into the Map project from the source drawing would not line up exactly with the points in the actual source drawing (when looked at independently of the Map project drawing).
Specify the Reference Point values. The reference point could be a benchmark that was used in a survey. It can be any point for which you know both the local coordinates and the grid coordinates. To specify the Reference Point values, do one of the following:
Select a COGO point from the drawing

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Click the Reference Point button.
Select a COGO point from the drawing.
The local northing and easting values are retrieved from the point database and are displayed in the dialog box.

Type the reference point's Grid Northing and Grid Easting values.

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Type a COGO point number

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Under the Reference Point button, type local northing and easting values in the Local Northing and Local Easting boxes.
NOTE  The local northing and easting coordinates are automatically displayed if you select a point from the drawing or if you type a point number.

Type the reference point's Grid Northing and Grid Easting values.

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Type coordinate values in the boxes

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Under the Rotation Point button, type local northing and easting values in the Local Northing and Local Easting boxes.
NOTE  The local northing and easting coordinates are automatically displayed if you select a point from the drawing or if you type a point number.

Type the reference point's Grid Northing and Grid Easting values.

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To define the rotation angle for the transformation, do one of the following:
Select a COGO point from the drawing

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Click the Rotation Point button.
Select a COGO point from the drawing.
The local northing and easting values are retrieved from the point database and displayed in the dialog box.

Type the rotation point's Grid Northing and Grid Easting values.

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Type a COGO point number

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Under the Rotation Point button, type the point number in the Point Number box.
The Local Northing and the Local Easting coordinates are obtained from the point database and entered into the dialog box.

Type the rotation point's Grid Northing and Grid Easting values.

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Type coordinate values in the boxes

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Under the Rotation Point button, type local northing and easting values in the Local Northing and Local Easting boxes.
NOTE  The local northing and easting coordinates are automatically displayed if you select a point from the drawing or if you type a point number.

Type the reference point's Grid Northing and Grid Easting values.

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Type the rotation to grid north

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In the Rotation to Grid North box, type the grid north rotation.
The rotation to grid north is the difference between the local coordinate system's north meridian and the grid north meridian (of the current zone).

If you are using True North, then this value may equal the convergence angle. If you are using magnetic north, then this value would be derived from the declination angle and the convergence angle.



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Click OK.
IMPORTANT  Always save the drawing after you change the Transformation Settings if you are going to use the drawing in a Map project and perform queries on it. The changes you make to the Transformation Settings are not recognized in a Map query if you do not save the drawing first.

[Dent Cermak]

So, if I am reading this correctly, I have numerous way to set the scale factor. One being, checking the USER DEFINED box and then entering  a scale factor or a combined factor into the box. Correct??
that's what I am doing and it appears that the scale factor is not being applied. The coordinate values do not chnge from when I ran them up with no adjustment. 

[Dinosaur]

I haven't tried to do this myself and don't even have Survey installed at the moment so I can't be much more help.  If you haven't got an answer by this evening, I will put out an SOS call to someone I KNOW who can get it set up for you.

[Dent Cermak]

PLEASE DO!!  I AM SOFA KING LOST!!

NOTE  If you specify a User Specified grid scale factor and then clear the Apply Transform Settings check box, the scale factor is still used in Autodesk Survey calculations. If the Scale Factor check box is selected in the Survey Correction Settings dialog box, then this scale factor is applied to all horizontal distances in Survey measurement calculations. For example, if you specify a horizontal distance of 500 feet to a sideshot point using the Survey Sideshot Instructional method, and the Scale Factor check box is selected and the scale factor value is set to 0.5, then the horizontal distance to the sideshot point will be 250 feet. The Survey Command Language command SF (SCALEFACTOR) always overrides the value specified for the scale factor in the Transformation Settings dialog box.

I think that item is the key and what i cannot find. Ifind the transformation box easily, but it does not seem to work. Where lies the mysterious Survey Correction Settings dialog box ??  :realmad:

[mjfarrell]

Dent,

To change the Survey corrections settings

From the Projects menu, click Edit Drawing Settings to display the Edit Settings dialog box.
In the Program list, click Survey.
In the Settings list, click Corrections.
Click Edit Settings to display the Survey Correction Settings dialog box.

Choose the correction features that you want to apply to your data:
Curvature & Refraction: Corrects measurement calculations based on the curvature of the earth and refraction of the sun.
Sea Level: Includes corrections for sea level in all measurement calculations.
Atmospheric Conditions: Applies corrections for atmospheric conditions (pressure and temperature).
Horizontal Collimation: Works with FACE 1 and FACE 2 measurements only.
Vertical Collimation: Works with FACE 1 and FACE 2 measurements only. All vertical angles are converted to zenith.
Scale Factor: Includes corrections for the scale factor specific to horizontal distance in all measurement calculations.
EDM-Prism Eccentricity: Includes corrections for EDM and prism offsets in all calculations.
Click OK.
 
THEN, in the TRANSFORMATION SETTINGS box enter the values that you want Land to Apply when it uses the various transformation settings ON.  In drawing settings, you are basically turning on a switch,
so that WHEN, and or IF you need to apply a particular transformation.

Importing the Field Book should then result in the transformations actually being applied.
Because you toggled them on, in the prototype, AND you toggled ON the Apply transformation
button, and entered the correct values in the right boxes.

[Dent Cermak]

I FIGURED IT OUT!!   :ugly:    I FIGURED IT OUT!!    :ugly:
The data I am working with is from GPS and therefore already on the appropriate SPC system. The Transformation and zone thing is to allow you to translate from a local project grid to SPC. When I went that way, the system got real confused.
All I need is the application of the scale factor to existing SPC's. In R14 you had to check the scale factor box in the prototype setup AND in the project setting. Same is true in LDD3 and 5. It's just finding where they hid it and what they renamed everything to. The EDIT DRAWING SETTINGS is indeed the starting place as you listed (Thank you! Thank You!!!). That sets the scale factor in the drawing. Then you ALSO have to go under PROTOTYPE SETTINGS under the PROJECT menu and click the Survey and then Corrections and do the same thing to set the Prototype . Those 2 settings will then read and apply the scale factor that you enter at the top of your field book file.