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Location of Davy Jones's Locker?
Today we used the 2 Distance Offset routine in Topcon MAGNET Field to locate a property corner. The resulting location might be Davy Jones’s locker.
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14 Replies
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What’s even more awkward is there’s a pincushion out there.
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Are you sure you should be using USft? Could be the scale difference from INTft.
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Did you figure out what you did wrong?
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@ peter-lothian
We always use USft. We’re located in Orange County, FL, USA.
MH -
@ Norman_Oklahoma
No. It was necessary to do the 2 Distance Offset routine because we had poor latency under a tree and could not maintain a fix. I waited several minutes for the rover to go from float to fix. The software glitch was repeatable. We ended up locating the 2 offset points as topo points and calculating the property corner manually.
MH -
The point you created is the near the origin of the Florida east state plane coordinate system, or the 0,0. It appears that your software did not know where the distances were to be taken from, so it used the origin, perhaps the points were not defined in your project.
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@ levelheaded
The day before we used the 2 Distance Offset routine, we were able to locate the point directly. We wanted to locate the point again because when we did a Point to Line Inverse it was 6.56′ offset from the line that we were holding. We knew that wasn’t the case because the point lined-up pretty closely to other located points. I always thought the Florida East SPC System had its origin in Tallahassee. I found something on the Internet concerning the grid origin, but I can’t’ attach it to this reply.
I don’t know why the points wouldn’t be defined in my project. We’ve never encountered this problem before. Could this be due to a problem within the network? I’m going to forward this post to our network provider.
MH -
@ levelheaded
The day before we used the 2 Distance Offset routine, we were able to locate the point directly. We wanted to locate the point again because when we did a Point to Line Inverse it was 6.56′ offset from the line that we were holding. We knew that wasn’t the case because the point lined-up pretty closely to other located points. I always thought the Florida East SPC System had its origin in Tallahassee. Why is the origin (24.200000, 81.000000, or 24°12’00.0″N 81°00’00.0″E) in the attached file located in India?
I don’t know why the points wouldn’t be defined in my project. We’ve never encountered this problem before. Could this be due to a problem within the network? I’m going to forward this post to our network provider.
MH -
28 north and 81 east will put you in India. lat 28 long 81 will put you in India. 28 north and 81 west will put you in Florida. lat 28 and long -81 will put you in Florida. You have to beware how the software defines lat longs. Some made for the western hemisphere assume a west longitude others make you enter the negative sign for western longitudes.
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@ lurker
Thanks for schooling me on latitude and longitude. I really want to know where the origin of the FL SPC System is so I can figure out what happened last week.
MH -
Maybe this will help…
PROJCS["NAD_1983_CORS96_StatePlane_Florida_East_FIPS_0901", GEOGCS["NAD83(CORS96)", DATUM["NAD83_Continuously_Operating_Reference_Station_1996", SPHEROID["GRS 1980",6378137,298.257222101, AUTHORITY["EPSG","7019"]], AUTHORITY["EPSG","1133"]], PRIMEM["Greenwich",0, AUTHORITY["EPSG","8901"]], UNIT["degree",0.0174532925199433, AUTHORITY["EPSG","9122"]], AUTHORITY["EPSG","6783"]], PROJECTION["Transverse_Mercator"], PARAMETER["latitude_of_origin",24.3333333333333], PARAMETER["central_meridian",-81], PARAMETER["scale_factor",0.999941176470588], PARAMETER["false_easting",200000], PARAMETER["false_northing",0], UNIT["metre",1, AUTHORITY["EPSG","9001"]], AXIS["Easting",EAST], AXIS["Northing",NORTH], AUTHORITY["ESRI","103254"]] -
@ jimcox
PARAMETER[“latitude_of_origin”,24.3333333333333]
PARAMETER[“central_meridian”,-81]
PARAMETER[“false_easting”,200000]
PARAMETER[“false_northing”,0]
UNIT[“metre”,1,
AUTHORITY[“EPSG”,”9001″]]
These are the same parameters as the attached part of the NOAA Manual NOS NGS 5. I see now that the false northing and false easting are in meters. We use USft as seen in an above screenshot. So, the origin is south and east of Key West. Converting the origin to USft we have 0.00000 northing and 656,166.66667 easting. Thanks for the data. I appreciate it.
MH -
I wrote “I always thought the Florida East SPC System had its origin in Tallahassee.” I was wrong. A township is identified by its relationship to the intersection of the Tallahassee Meridian (the central north-south axis) and the Base Line (the central east-west axis). All townships are either Northwest, Southwest, Northeast, or Southeast of the intersection in Tallahassee.
MH -
Easy to be confused until one starts looking at the SPC numbers. The 0,0 point is probably not even in the same State.
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