Released: August, 2011
When it comes to keeping track of grid distance, ground distance or geodetic (ellipsoid) distance, the door is always open for gotchas. There’s just so much to keep an eye on: imported field data, coordinate reference systems, datums, projections, transformations, translations, scale factors, project elevations and more. That’s what we call the scary of geodetics, grid and ground survey data: the sheer amount of things to keep track of.
TPC Desktop 2011 tackles the scary of geodetics head on with our new Distance and Direction types. Whether you’re starting a new survey, entering traverse data, doing COGO or drawing a plat, TPC Desktop 2011 says, “just pick the Distance and Direction types you want. We’ll do the rest.” We even make it easy to learn how to do geodetics in TPC in our new Geodetic Learning Guide.
Since we’re adding geodetics, why not add the tools for cadastral surveys on the PLSS (Public Lands Survey System). You’ll find tools for single and double proportions, grant and irregular boundary adjustments, random line offsets and lots more. Learn more in our new Cadastral Learning Guide.
TPC can work with both coordinate distances derived from Cartesian coordinates (Northings / Eastings) and Geodetic distances derived from geodetic positions (Latitude / Longitude).
When you are doing a typical boundary or Topo survey, you are using coordinate distances. When you work with large tracks of land, you can switch to geodetic distances. TPC lets you switch easily between distance types with no wasted time.
Even the Personal edition of TPC Desktop 2011 now knows how to relate grid and ground distance. You can use a combined project factor or a project elevation, or enter a distance factor that matches another survey you are working with. Regardless of which Distance type you choose, TPC keeps track of which distance you are using in traverses, COGO and drawings. That’s right: switching between ground and grid distance on a drawing is as simple as selecting the Distance type. It’s that easy! And after all, it should be!
A survey can have one Coordinate Reference System (CRS) which relates it’s geodetic and rectangular coordinates. TPC computes coordinate distances by inversing between coordinates on the current CRS and applying the appropriate scale factor (converts between the grid plane and ellipsoid surface) and elevation factor (converts between the ellipsoid surface and the ground elevation). Since the CRS releates the coordinates of a point to its geodetic position, TPC can compute both a coordinate distance and a geodetic distance between any two points.
Coordinate directions are derived from Cartesian coordinates (Northings / Eastings) as opposed to geodetic directions which are derived from geodetic positions (Latitude / Longitude). Coordinate directions are referred to as Grid Bearing, Grid Azimuth .or just Bearing or North Az or South Az . Geodetic directions are always referred to asTrue Bearing or True Azimuth. TPC Desktop 2011 keeps them all straight using our new Direction types.
Even the Personal edition lets you choose between grid bearings and true bearings based on a project mapping angle or a manual mapping angle which you enter as needed. Just choose the Direction type you want in a traverse, COGO or a drawing and TPC does the rest.
A survey can have one Coordinate Reference System (CRS) that relates it’s geodetic positions and rectangular coordinates. TPC computes coordinate directions by inversing between coordinates on the current CRS and applying a convergence angle (also called a mapping angle) to generate a geodetic direction. Since the CRS relates the coordinates of a point to its geodetic position, TPC can compute both a coordinate direction and a geodetic direction between any two points.
Mean Course Convergence
We’re excited to offer True Bearings based on Mean Course Convergence. Whether you are doing a Direct or Inverse computation, TPC takes into account the direction at both ends of a course and means them for the computations. That means you can work seamlessly with the requirements of the PLSS or rest assured that you are extending an East-West line appropriately along a latitudinal arc. It’s the rigorous solution you expect when you need true geodetic positions.
Grid vs Geodetic Direction
Coordinate directions use the equation:
grid direction = geodetic direction + convergence (mapping) angle
In a state plane projections, convergence angles east of the central meridian are negative, while those west of the central meridian are positive. TPC keeps track of this for you and it displays and computes directions.
Geodetics are now as much a part of TPC as X,Y coordinates.
TPC is as comfortable computing a ‘geodesic’ as it is computing a straight line on a coordinate grid. And best of all, TPC makes it obvious when you are doing one and not the other.
Direct and Inverse Computations on the Ellipsoid
Everything to do with geodetics finds its start in the Direct and Reverse computations on the Ellipsoid. You specify the CRS (Coordinate Reference System) you are using the TPC has all it needs to relate geodetic positions to grid coordinates.
Geodetic vs. Grid Preference
TPC keeps it all straight (or curved) with an internal preference. Enter a geodetic position for a point and that point has geodetic preference. Enter a grid coordinate and it has gird preference.
This internal preference determines what gets held and what gets recomputed. A point with geodetic preference holds the geodetic position that was entered or computed, and recomputes the grid coordinates as needed. Points with grid preference hold the entered or computed grid coordinates and compute the geodetic position as needed.
Either way, you still get the scale factor and convergence angle for each transformation, and you don’t need to keep track of what needs to be recomputed yourself!
Geodetics Made Easy
The real beauty of using TPC Desktop 2011 for geodetic computations comes in how simple we’ve made it. Choose a Distance Type and Direction Type anywhere in the program and TPC follows right along. Enter geodetic bearings and ground distance, compute a geodetic inverse with COGO and plot geodetic lines labeled with geodetic distance and direction. We’re making it sound pretty simple, and it is.
There’s even a new Geodetic Learning Guide that will help you start using geodetics in TPC right away.
Traverses, COGO and Drawings
Each traverse includes the new Distance and Direction types as part of the advanced traverse format. Select the types you need and foresights and inverses in the Traverse View track right along with you. The Traverse View status bar even displays information like Mean Course Convergence to help you keep it straight.
COGO dialogs let you select the Distance and Direction types right inside the dialog.
Drawings let you choose Distance and Direction types, then update all their annotations and areas to match. Labeling a drawing with ground distance and true bearing is now as easy as using grid distance and grid bearings.
Figure: In the Traverse View shown here, we are computing True Bearing and geodetic distance at the project elevation per the Public Lands Survey System. The data is easy to see and reference.
The COCO routines in TPC are completely aware of grid coordinates and geodetic positions. They know that the length of a geodesic is not the same as the length of a straight grid line between the same two points. They understand a latitudinal arc between them may have a different distance yet. All the COGO routines know the difference between a grid, ground and geodetic distances. And the same holds true for grid and true bearings.
Figure: The Random Inverse dialog shown here displays the Distance and Direction types in the title bar. You can also expand options to select a different distance and/or direction type.
Some dialogs, like the Offset to Line shown below, also include PLSS constraints to work on a latitudinal arc.
There are ways to force Cartesian coordinate based software like CAD to draw geodetic lines (actually appear as arcs on a large scale drawing) but none of them are simple to use or understand. That all changes with TPC Desktop 2011.
TPC Desktop 2011 makes drawing geodetic lines as simple as selecting a Distance Type and Direction Type. You used these same selections to enter your data, compute your COGO and now to create your map. Just tell TPC what you want to draw and it does the rest.
We’ve even included drawing variables you can put into your drawing that show the Distance and Direction types being labeled. TPC makes it very easy to keep track of whether your drawing is grid distance, ground distance or geodetic distance.
Even areas track with the Distance type you select. Choose a geodetic distance type and TPC the computes the geodetic area. Computing an area on the PLSS just get really easy.
Here is an example of a dependent resurvey. TPC Desktop 2011 drew the lines and labeled them per the PLSS. TPC includes the template for this drawing along with other goodies like pre-defined blocks for section corners, all of which make working on the PLSS very easy in TPC Desktop 2011.
The PLSS (Public Land Survey System) is unique in many aspects including its use of cardinal direction and ground distance. Computations in the PLSS are done per ‘The Manual of Surveying Instructions’. TPC Desktop 2011 follows the 2009 version to the letter (including the corrections made after its release).
You’ll find new tools in TPC Desktop 2011 for Single Proportion, Double Proportion, Grant Boundary, Irregular Boundary, Rectangular Limits, geodetic areas and lots more.
We thought long and hard about how to make PLSS computations available to everyone who uses TPC Desktop. The trick we settled on was to add a ‘PLSS’ hints to commands that are used the PLSS methods.
When you need offsets to a true line, look for the PLSS hint. When you need to restore one or more lost corners, look for the PLSS hint. You’ll catch on right away.
We’ve recorded typical PLSS routines in a set of videos that will help you understand how to make the change from Cartesian coordinates to the PLSS.
Cadastral Learning Guide
The new cadastral learning guide provides step-by-step instructions to the tasks you watched in the on-line videos.
CMM, GMM and CAPD
For those of you familiar with the computer programs CMM, GMM and CAPD, we think you find all the tools you need right here in TPC Desktop 2011. Try our least squares adjustments and true line offsets. Look for true cardinal offsets in our single and double proportions. Check individual course adjustments in our grant and irregular boundary adjustments.
We think you make the jump to TPC Desktop 2011 pretty easily. And remember, we’ve got printed learning guides and on-line videos to help you out.
This is the Single Proportion dialog. Notice that it helps you keep track of data that is Retrace (measured) and Record data.
TPC provides the tools necessary to perform a survey that meets the 2011 MINIMUM STANDARD DETAIL REQUIREMENTS FOR ALTA/ACSM LAND TITLE SURVEYS (effective February 23, 2011) as adopted by American Land Title Association and National Society of Professional Surveyors.
Meeting the 2011 Relative Positional Accuracy Minimum Standard
The 2011 standard defines RPP in section 3E as follows: “Relative Positional Precision” means the length of the semi-major axis, expressed in feet or meters, of the error ellipse representing the uncertainty due to random errors in surveyed property relative to the monument, or witness, marking any other corner of the surveyed property at the 95 percent conficient level.
Section 3Ev further states that “The maximum allowable Relative Positional Precision for an ALTA/ACSM Land Title Survey is 2 cm (0.07 feet) plus 50 parts per million (based on the direct distance between the two corners being tested).”
The Least Squares adjustments include pre-defined APriori values that contain the Least Squares solution to this stated Relative Positional Accuracy at the 95% confidence level. If you do a Least Squares traverse or network adjustment using these pre-defined APriori values, the solution TPC computes will meet this standard.
The Relative Position Precision (RPP) Report
In addition to checking the Su values, you can also ask TPC to include the Relative Position Precision report.
This report accounts for the line of sight distance between each corner be adjusted and the fixed control points in the survey. Although this does not allow the flexibility to compute RPP between any 2 corners, it does provide maximum allowable errors (consider this to be the maximum Su allowed). You will want to check the Su values of survey corners with the maximum values computed in this report. See the example below.[ Error Ellipse ] and [ Adjusted Coordinates ] both provide Su
Station Su (semi-major axis)
ALTA.drt – this template includes many of the minimum drawing requirements such as north arrow, scale bar, etc. It also contains the certificate required if your survey precision complies wth the minimum standard of 0.07 FT +- 50 PPM. If the relative positional accuracy of your survey exceeds these limits, you can replace the certificate included in this template with the certificate found in the pre-defined ALTAExcd.dxf drawing object.
The program folder\Blocks\ALTA\ folder contains blocks you can insert into your drawing as part of the minimum requirement.
ALTACert.dxf – The certificate of compliance with the minimum standard. You will need to edit the text in this block for each survey. This certificate is already included in the ALTA.drt template.
ALTAExcd.dxf – The certificate of exceeding the minimum standard. You will need to edit the text in this block for each survey. If the relative positional accuracy of your survey exceeds the minimum limits, you can replace the certificate included in the ALTA.drt template with this block.
A Lot table allows you to include information about traverses (lots) that might otherwise clutter up a drawing. Any lot label in a drawing can be placed in a Lot Table where each row represents a labeled lot in the drawing.
Each drawing can contain only one lot table. For other drawing tables see Drawing Tables .
|Lot||Name||Acres||SqFt||LinError||<- column headings|
|T1||Lot 1A||1.75||76,230.0||0.07||<- table item|
Figure: In this example, we’ve requested an automatic lot reference, T1. We could just as easily used the lot name ‘Lot 1A’ to reference the lot.
Lot table areas track right along with the distance and direction types you are using in the drawing. Choose from any of the grid, ground or geodetic options.
TPC Desktop 2011 includes the latest drivers for AutoCAD and Microstation.
Starting in TPC Desktop 2010, you can read and write surfaces in DWG and DGN files. You’ll find new options and improved compatibility in TPC Desktop 2011.
You can export any drawing in TPC as a DWG or DGN file. Share your drawings with architects and engineers who don’t use TPC because they’re not surveyors like you. They’ll get layers, blocks, surfaces and pretty much everything they need to pick up right were you left off in TPC.
With the Premium and Professional editions of TPC, you can also import drawings from other CAD programs right into your drawings. Select a curb return right out of the drawing, convert it to survey points and send it off to your data collector, total station or GPS.
All COGO dialog boxes now have the buttons to minimize and restore the dialog. Minimize any COGO dialog and it drops out of the way, to the bottom of the TPC Desktop.
We put this in because a number of you asked for it. You wanted more room to work on the desktop, while keeping the COGO dialogs handy.
Minimizing COGO dialogs is just a little thing, but it gives you more room to work on your TPC Desktop, even if you are running on a notebook computer.
Be sure to watch our videos on using the TPC desktop to learn more tips and tricks.
TPC Desktop 2011 includes two new learning guides and a new license guide for network installations.
Geodetic Learning Guide
This learning guide introduces you to surveying geodetically using TPC Desktop 2011. Learn how we’ve taken the scary out of geodetics with the new Distanceand Direction types.
We cover the three ways you’ll interact with geodetics:
1) traverses, 2) COGO and 3) Drawings.
Cadastral Learning Guide
Learn how to survey on the Public Lands Survey System using TPC Desktop 2011. You find that TPC knows all about the requirements of the PLSS, providing straight forward options for ground distance at project elevation, true bearings and latitudinal arcs.
You’ll also find special PLSS routines for restoring lost corners, offseting random lines to true lines and accouting for apparent misclosure in areas. If you’ve read the 2009 Manual of Instruction, you’ll recognize a lot of what is in TPC Desktop 2011.
TPC now includes special features for those of you who work on a network. Now you can select a license server on your network and install TPC one place. The license server checks out licenses as needed and let’s your IT folks keep track of it all.
And for those of you who unplug your notebook computer from the network, there is a new commuter license you take with you.
Updated Learning Guides
The other learning guides have been updated also. You’ll find updated screen shots and some new topics to choose from.
Have you wished you could select a bunch of objects in a drawing and change their color, line type or font?
Well now you can with the new Set Properties command.
Change the properties you want to apply to the selected objects and TPC sets just those properties. Talk about a real time saver.