Thursday, December 9, 2021

Vasileios (Vas) Kalogirou, RPLS, PLS

Vice President, Survey Practice Leader

Halff Associates

National Geodetic Survey (NGS) is updating both the HORIZONTAL and VERTICAL DATUMS in 2022. The presentation will depict the impact of Surveying, GIS and Engineering projects based on the design and configuration of the NEW State Plane Coordinate Systems (SPCSs) and the Low Distortion Projections (LDPs).

The learning objectives of this presentation will be to have a better understanding of:

  • The principles of the new NGS 2022 Datum & LDPs
  • The impact of the new DATUMs to various geographic regions of Texas after 2022
  • Managing historic and new small-scale & large-scale Engineering projects before and after 2022

Vas started his surveying career in Greece 25+ years ago through his surveying family business and is a third generation Surveyor.  While working in the surveying industry he received a 5-year Bachelor’s Degree in Land Surveying Engineering from the Aristotle University of Thessalonica, Greece in 2001. At the end of the same year he received his license as a Professional Land Surveyor in Greece and then moved to the United Kingdom where he received his Master Degree in GIS in 2003. At the end of 2003 he served in the Greek Artillery where he continued working as a surveyor for various expeditions.

Vas moved to Dallas in 2005 and started working for Halff Associates, which is where he is still employed today.  Since then, he managed several commercial improvement Surveys, right-of-way Surveys, FEMA Elevation Certificates, Oil & Gas and topographic surveying projects in various parts of Texas and other States.  Vas is a Licensed Surveyor in five (5) States, including the State of Texas. Since 2007 he has been coordinating the RPLS & SIT study groups in the DFW area while serving as the President of the TSPS Chapter 5 in 2021. Vas is also an adjunct professor teaching the courses of GIS and Geodetic Surveying at DCCCD North Lake College since 2015. He is currently the Survey Practice Leader at Halff Associates, but most importantly, he is a devoted family man who really enjoys surveying.  

Impact of NGS 2022 DATUM & Low Distortion Projections (LDPs) to Engineering Projects

Sunday, July 26, 2020

WKT Projection information

WKT (well known text) files are used by GIS and related programs. Thanks to Jeremy Bender, LS-691, if you require such files he has created two text files covering the LDPs for the counties in Nebraska, one for the TM projections and one for the LLC projections.  The projections for Lancaster County and Platte County are those designed by each county and were not designed by the State Surveyors Office.  Find the county your are looking for in the TM or L1SP text file.  Copy the entire line of text for that county.  Save it into a text file.  Change the extension of the file from "txt" to "wkt".  Example name change, Gage LDP.txt to Gage LDP.wkt.

Also Jeremy has provided the following links to free coordinate converters

The first one is a free program that can be downloaded called, SeisWare Coordinate Converter.

The second is located online at a website called MyGeodata Cloud

The SeisWare Coordinate Converter will allow the use of the WKT.  While MyGeodata Cloud will allow the input of coordinate systems in PROJ4 coding similar to QGIS.  It should be noted that in the latest versions of QGIS utilize WKT (Prefered Method by QGIS) or Proj4 (Old Method) and can be copied and pasted into the Custom Projection dialog box.

Both the WKT and Proj4 formats are located in the spreadsheet.

All files available in WKT link above.


Thursday, February 14, 2019

Trimble GPS Custom Coordinate System

In order to upload the Nebraska County LDP projection parameters into Trimble Business Center or a Trimble Survey Controller, you will need to copy the custom.csd file into the appropriate directory for both to work. Follow the instructions for working with trimble CSD files on the PDF. The custom file is named "current.csd". I have eliminated all of the excess coordinate systems from other continents from the file and reduced the list to the most commonly used files in North America.

Here is the link to the instructions and the custom coordinate system file.

For the Trimble files click here.

If you have any questions, contact me at the email address below:

casey.sherlock@nebraska.gov

Tuesday, March 14, 2017

Submitting corners to the NE PLSS using SurvCE raw files

If you are using Carlson SurvCE for your data collection then it’s pretty easy to get the data you need out of the raw file if you want to submit corners to the Section Corner Database.  There are just a few steps you need to take.

First, a quick examination of a SurvCE raw file.  Here’s a portion of a raw file of mine:

--DT01-12-2017
--TM12:49:43
--User Defined: SSO-RichardsonCo
--Equipment: GRX1  SN:GRX1/S 665-00170
--Localization File: None
--Geoid Separation File: \DCFiles\NebKsMoArea.gsf
--GPS Scale: 1.00000000
--Scale Point not used
--Base Configuration by Previously Surveyed
--DT01-12-2017
--TM12:49:43
--Point Used: 316
--Base Rod Hgt: 5.282
--Antenna Type: [SOKGRX1         NONE],RA0.0890m,SHMP0.0552m,L10.1101m,L20.1061m,--TPS p/n:01-090101-08
BP,PN316,LA40.033186617300,LN-95.361100137200,EL275.0391,AG1.500,PA0.110,--
--Antenna Type: [SOKGRX1         NONE],RA0.0890m,SHMP0.0552m,L10.1101m,L20.1061m,--TPS p/n:01-090101-08
--RTK Method: CMR+, Device: Internal Satel
--Entered HR: 5.9055, Vertical
LS,HR6.2667
GPS,PN0284E09,LA40.030075609518,LN-95.351404448716,EL255.638283,--2 424
--GS,PN0284E09,N 35360.5788,E 134662.1040,EL932.4832,--2 424
--GT,PN4025,SW1931,ST415750000,EW1931,ET415871000
--Valid Readings: 120 of 120
--Fixed Readings: 120 of 120
--Nor Min: 35360.5657  Max: 35360.5932
--Eas Min: 134662.0903  Max: 134662.1156
--Elv Min: 932.4576  Max: 932.5045
--Nor Avg: 35360.5788  SD: 0.0052
--Eas Avg: 134662.1040  SD: 0.0042
--Elv Avg: 932.4832  SD: 0.0103
--HRMS Avg: 0.0192 SD: 0.0001 Min: 0.0190 Max: 0.0199
--VRMS Avg: 0.0272 SD: 0.0005 Min: 0.0260 Max: 0.0283
--HDOP Avg: 0.6906  Min: 0.6812 Max: 0.6930
--VDOP Avg: 0.9796 Min: 0.9345 Max: 0.9925
--PDOP Avg: 1.1986 Min: 1.1564 Max: 1.2105
--Number of Satellites Avg: 17 Min: 17 Max: 18

As you can see, I record all the accuracy information that Carlson offers.  I record the number of readings, max / min / etc.  I maintain this “unedited” raw file for legal reasons but usually will process my raw files into what I call a “Packed” format which is what you need for submitting to the Online database.  Basically there are only a couple of things that need to be done:

  1. Convert the Elevation (in the line starting GPS) from the L1 Phase Center to the ground.
  2. Remove all extraneous lines so all you have is the Lat/Long/HAE.

Here is the process I use. I wrote a little program that takes the line reading LS,HR6.2667 (which is the L1 rod height) and subtracts that height from the elevation listed on the GPS line. For the GPS shot (Point 0284E09) the calculation would be the height above ellipsoid in meters (255.638283) minus the rod height (6.2667) in feet.

HAE = L1 – Rod, or HAE = 255.638283 - 1.910 = 253.7282.

If the base station (from the line that starts with BP,) has an accurate NAD83(11) position, then that is the only conversion necessary.

The program called “PackRaw.exe” does the computation above, and strips out all the unnecessary lines, leaving JUST the GPS shot. I’ve also supplied the QB64 basic source code PackRaw.bas if you want to see how the program is written.

This program is written in QB64 basic and is designed to be as small as possible. Put the executable in the same directory as your raw file because you have to type in the raw file name. The program creates a second file with the same name and adds “Pack” which is the stripped-down version of the raw file. As an example an input file named “RichCo.rw5” will create a file named “RichCoPack.rw5”

Running the program, the output for this raw file would look like this:

LS,HR0.000
GPS,PN0284E09,LA40.030075609518,LN-95.351404448716,EL253.7282,--2 424

The program puts a “revised” rod height in (zero), and then leaves only the GPS shot. This is the basis for the file to submit.

I record all the accuracy data so my raw files get pretty large. I create a “Packed” file every couple of months and keep the unedited raw file for archive purposes.

Once you have a packed raw file run it through WinDMS-DDEG selecting conversion 15. The GPS, PN line structure is stripped off and leaving the Point, Latitude, Longitude, Height, Description. Verify the point number is the correct point ID and rename the text file to the requested format (LSnumber-Date-Frame.txt) and submit!

Hope this helps. If you spot a mistake or want more information let me know. If you have similar routines that you use with equipment other than Carlson let me know. Thanks.

Thursday, September 15, 2016

Setting up a Leica CS15 Controller to use LDP parameters

Mike Caniglia with TD2 and Dan Kahm with A&D have taken the time to create how-to files to create and import LDP parameters for the Leica CS15 Controller. The Create Parameter how-to is here and the Import Parameter how-to is here. The TRFSET.DAT file which contains parameters for all the counties except Hall, Platte and Lancaster may be downloaded here.

Thanks to both for taking the time to do all this.

Thursday, July 21, 2016

Setting up your SurvCE data collector to work in an LDP

As most of us aren't used to getting set up to work strictly in an LDP system, there's a number of things that maybe aren't especially clear about how to get Carlson set up.  We're used to using a ground-to-grid scale, or maybe a localization file.

The end-goal of an LDP is that neither a scale nor a localization is necessary.  The only conversion is from Lat/Long to local North/East.  Scale, rotation and coordinate conversion is all handled solely by the projection parameters.

A quick how-to for getting set up and working in the LDP is here.

Wednesday, June 29, 2016

SurvCE 5.0 - adding new projections

The linked documents will show you how to add the LDP parameters to SurveCE V 5.01.

A Lambert Conformal Conic 1 SP for Adams is here.
A Transverse Merecator for Antelope is here.

You can also download the parameter files using the "SurvCE parameter files" link. The files can then be loaded into your data collector and Carlson Survey desktop.

The actual pages from the SurveCE manual are here.

A brief article from Mircea Neacsu explaining the difference between WGS84 and GRS80 is here. The article is dated but the information is still relevant.

I would appreciate any help with posting similar information for Leica, Trimble, Topcon, Sokkia, Spectra, etc. Contact me if you can help.