Mass Highway Geodetic Control Site

[+choude]

Hello all,

 

For those of you looking for BMs in Massachusetts, the Mass Highway Department offers a website that maps out both NGS marks with PIDs as well as state marks (MAGS) that have been set all over the state. Very useful for finding references to those weird marks that show up when you're looking for something else.

 

The one downside to the site for us GPSr users is that the coordinates on the datasheets are all in UTM format. I haven't had the best of luck getting things converted, but I'm sure one of you out there knows more.

 

I was using a spreadsheet from http://www.uwgb.edu/dutchs/UsefulData/HowUseExcel.HTM but I couldn't get things to reconcile. I got as far as figuring out that I was in zone 19 and that something must be off in the units of measurement from the datasheets to the spreadsheet (a factor of 10 or so).

 

If anyone knows of a web based conversion or if you're more of the mind to play with the spreadsheet, drop a reply here.

 

Thanks!

[+Black Dog Trackers]

Well, seeing since no one else responded all day, I tried the first example in the referenced spreadsheet's tab called Batch Convert to UTM Lat-Lon and it worked OK compared to jeep.com's translator page. All the decimals weren't the same but it was good enough for our GPS units.

 

The Mass site gives UTM coordinates that don't agree with the NGS coordinates when a point is in the NGS database. Could it be that the Mass. site has a bad translation program?

[TerraVador]

You can translate the UTM coordinates here:

http://www.ngs.noaa.gov/TOOLS/utm.shtml

 

It looks likes most of the MHD points are in NAD27. After you translate from UTM to Lat/Lon, you will then have to do the datum shift to NAD83 here:

http://www.ngs.noaa.gov/cgi-bin/nadcon.prl

 

This looks like a very tedious way to do this, point by point. If someone has a better way, chime in.

[Gnikhog]

Actually the Mass Highway Geodetic Data Sheets identify location using the Massachusetts State Plane Coordinate system. You can convert these coordinates to the standard ddd mm ss.sssss format using the program spcs83.exe which can be found on the NGS website. The program can be used interactively or in batch mode. Be sure to read the accompanying user's guide!

 

My experience has been that these datasheets are useful for horizontal controls only as there are no coordinates provided for vertical controls - at least in my area. Also, beware of out-of date Data Sheets that are still in NAD27 (U.S. Survey Foot) format as these coordinates are not compatible with spcs83.exe

 

/John

[+choude]

Thanks Gnikhog! I couldn't figure out why the conversion kept coming up as a point near the equator!

 

It is a little tedious but I might whip up a quick perl script to pull the sheets and dump the data out. That's the nice thing about consistently formated data is that you can programmatically get what you want out of it.

[ArtMan]

It is a little tedious but I might whip up a quick perl script to pull the sheets and dump the data out.  That's the nice thing about consistently formated data is that you can programmatically get what you want out of it.

I hate when people talk about whipping up a little code. I've tried a couple of those teach-yourself-Perl books with no perceptible increase in my programming skills. Maybe I'm destined to be no better at computer languages than I've been at French, Spanish, Dutch, Czech, Arabic, Hebrew and American Sign Language. (sigh)

 

-ArtMan-

[holograph]

I hate when people talk about whipping up a little code. I've tried a couple of those teach-yourself-Perl books with no perceptible increase in my programming skills. Maybe I'm destined to be no better at computer languages than I've been at French, Spanish, Dutch, Czech, Arabic, Hebrew and American Sign Language. (sigh)

At least with programming languages, you don't have to learn pronuciation or understand the spoken word. You could also try Python, which is a little less idiosyncratic than Perl. Having said that, all the "extreme benchmarks" statistics gathering and data mining was done in Perl, which has some powerful features for extracting data from documents like datasheets.

 

Unfortunately, it seems to be true that any general-purpose language that is rich enough to do useful things is always rather complex, especially for beginners, because they have to learn all the conventional general programming idioms and patterns as well as a language's syntax. It definitely takes a substantial investment of time before it's possible to "whip up a little code".

[+Black Dog Trackers]

I've tried perl. I prefer gawk. Simplicity is elegant. I don't blame anyone for not liking perl.

 

To 'whip up' means thrashing a liquid so very hard that after a while you finally make foam.