MRAS

Go ahead and send me the .gpx file. I can generate the hh file from that. Also, send me the state(s) and counties that have the hh positions in the text. I will go ahead and mine them: marchershee@wildblue.net

On 4/10/08 539 additional hand-held postions for benchmarks were loaded into the NGSIDB. Keep 'em commin', keep 'em commin'...

I created a tool to extract geographic positions and create HH files from descriptive text. I'm going to do all of the counties in Maryland over the next several weeks. If anyone knows what states/counties have a lot of bench mark descriptions with geographic positions in the text, please let me know and I will mine them too.

The following Benchmarks now have upgraded Handheld GPS positions: EZ1592 EZ1590 FY1988 FY1989 EZ1635 EZ1630 HV8270 HU0734 HU1010 HV8270 HU2577 HU0637 HU2560 HU2561 Check them out!

Good news! Gethvlst V 5.05 is now available on NGS's website: http://www.ngs.noaa.gov/PC_PROD/pc_prod.shtml With Version 5.05, one can create a HH file directly from a .gpx file. After creating the HH file, there is a tool that will check the HH file against NGS's database to make sure there are no problems with it. What could be easier? I sent March's finds to NGS and they should be updated shortly. I am a little discouraged though. I was hoping on being inundated by HH files, but I have only received one so far from Paul. Send your HH files to: marchershee@wildblue.net

Sorry for the confusion. To most folks the term 'Bench Mark' means any geodetic control point (Horizontal or Vertical). To surveyors 'Bench Mark' is a control point of known elevation (Vertical control). Horizontal control points are usually triangulation stations, traverse stations, or GPS stations, and are shown to 5 decimal places of Lat/Lon. There are about 4 times as many vertical control points as there are Horizontal control points, at least in Maryland. The export procedure in Gethvlst creates a tab-dlimited text file for import into MapSource, which could then be uploaded into a GPS reciever, if Garmin ever decides to create an import routine from that type of file. I probably jumped the gun on that one. I am using MapSource V6.0 to download my receiver. I Then use 'Save As' in MapSource to create the tab-delimited text file. I then use the 'Tools>Convert Garmin to HH' within Gethvlst to convert the Garmin tab-delimited file to a HH.txt file. The last column is the agency code; use 'GEOCAC'. I retired from MDOT State Highway Admininstration in June of 2005, so most of my finds are shown as 'MDSHA'. Here are a couple that you can check out: HU0937, HU0938. Of the handful of 'loaders' that work at NGS, only two of them have used the Load_HH program that I am aware of. Both of them are busier than one-legged people in a butt-kicking contest. As it takes about 15 minutes to load a 'clean' HH.txt file, I would much rather send them a single file of 1000 points instead of having 1000 people send them files of a single point. For those recoveries that contain positions in the descriptive text, send me a list of PIDs for those points.

First, a little background. I am a licensed surveyor in Maryland with over 36 years of experience in recovering, plotting and using geodetic control. I am also a programmer under contract to NGS to provide windows-based software and training. In regards to recovering and positioning geodetic control: The load_HH process is completely independent from the recovery web page. You should enter a recovery note via the web page if it has been serveral years since the last recovery. However, you can update the position of the mark anytime, even if someone recovered it yesterday, last week, last month, or last century. Here is how it works: If the PID and designation match those in the NGS IDB and the hand held postion matches the database position within 10 seconds, and the precision of the new position is as good as or better than the precision of the IDB position, the position will be updated with the new HH position. As most bench marks have scaled positions, the GPS postion will be at least 10 times better. The load_HH process only updates the position of bench marks and can handle any number of marks. HH1 is for hand held positions determined by Differential GPS positioning (DGPS) and is expected to be accurate to less than one meter. This type of system usually costs from $2,000 to $15,000. HH2 is for Autonomous GPS positions (AGPS) which are expected to be accurate to less than ten meters. Most folks have HH2 equipment. If you are using a hand held GPS unit and software other than Garmin that can output a text file of PIDs, Designations, and positions, you can use the 'Tools>Convert delimited text file to HH' procedure in Gethvlst to create the HH.txt file. The HH.txt file is simply a pipe-character (|) delimited ASCII text file that can be created by any text editor. See Gethvlst documentation for file format.

To create the HH file: Download the reciever with MapSource. Next, click 'File>Export'. When the file box appears, select 'Text (Tab Delimited) and give it a file name. Next, start Gethvlst and click 'Tools>Convert Garmin to HH'. Select the file and click okay. For agency symbol, enter 'GEOCAC' and click 'Okay'. Send the HH.txt file to me and I will see that it gets posted to the database (it usually takes about a week or so, depending upon how busy they are). NGS has no automated way of updating the positions from the descriptive text, but they do have a program for updating the position from a HH.txt file. Once the position of a bench mark has been updated and you download the new data, it will plot a lot closer with Google Earth and Delorme Street Atlas than it did from the scaled position. If you want a good example, download the data for Talbot Co., MD.

If you want a free program that retrieves, sorts, plots, and works with geodetic control datasheets, this program is for you. It is called Gethvlst and can be downloaded from: http://www.ngs.noaa.gov/PC_PROD/pc_prod.shtml There is a routine in this program which can take a tab-delimited file from Garmin MapSource and create a hand-held input file. (Tools>Convert Garmin to HH) When getting a position on a bench mark, use the PID for the point name and the designation (exactly as it appears on the datasheet) for the note. If you send me the HH file, I will get the bench mark positions for the points you recover updated on the official datasheets. Make sure your Garmin is set to NAD83 and outputs in DDMMSS.s, DDDMMSS.s Note-The NGS on-line recovery page does not have a place for handheld positions. Please DO NOT put handheld positions in the recovery note! You can send your HH files to: marchershee@gmail.com