To continue the discussion of graphical conventions used in the drafting of boundary survey maps, here's an example of a map I produced earlier this year in connection with yet another lawsuit. What was at issue in the lawsuit was the proper location of the roughly 125 feet of boundary between two lots in a subdivision platted in the 1950's on a variable-level lake. Naturally, the record subdivisions plat was not any marvel of clarity and the quality of surveying that produced it was sub-marvellous as well. For the purposes of arbitration, I generated a two-part map accompanied by a report.
One part of the map was this sheet:
The detail of the map in the vicinity of the line in dispute was this:
The second part consisted of the monument descriptions and the line and curve annotations, together with all of the record calls for those lines and curves appearing in prior conveyances.
Even in the absence of the table of monument descriptions, note how the double-circled symbol for a controlling monument readily shows the logic of the construction of the various lines and explains why the construction was not forced to use other monuments of later origin inconsistent with the original surveys that marked the various boundaries.
PUTTIN' ON THE POPCORN HERE....
CARRY ON. 😀
It appears that the previous surveyor left you enough information to retrace (and potentially mark on the ground), his interpretation of where the 670' elevation contour lies by using only 2D measurements. How would the future surveyor place your correct contour on the ground? Was that information irrelevant to the survey, or is the information provided elsewhere on your mapping?
> It appears that the previous surveyor left you enough information to retrace (and potentially mark on the ground), his interpretation of where the 670' elevation contour lies by using only 2D measurements. How would the future surveyor place your correct contour on the ground?
Well for starters, the 670 ft. elevation contour "as established from the US Geological Survey benchmarks" (or words to that effect) was the boundary of the tract conveyed to the subdivider. Here is how the original surveyor of the subdivision represented the 670 ft. elevation on the plat the sudivider executed in 1950:
Note that Lots 5 and 3 are shown as having a common corner on what is explicitly labeled as the 670 contour.
Then, after selling only one lot, the subdivider executed a resubdivision plat in 1953. Note that the meanders of the 670 ft. contour are shown somewhat differently along the boundary of Lot 5 but both Lots 3-B and 5 have a common corner on the 670 ft. contour according to the resub plat.
In other words, the surveyor who laid the subdivision out in 1950 and 1953 missed the 670 ft elevation contour by about 125 ft. at the common corner of Lots 5 and 3-B. The question was how to locate the line between the two lots that the plat showed to have only one common corner, but so that it actually did run to the boundary of the land subdivided, the 670 ft. contour "as established from the US Geological Survey benchmarks". The delineation of the 670 ft. contour on both the 1950 and 1953 plats was in gross error and was properly viewed merely as a meander line at best.
I notice you provide every course with a line #. I assume that is so they can be easily referenced in court proceedings?
Gawd Almighty Kent, that's the ugliest North Arrow I've seen since ACAD 3 or so.....
🙂
> I notice you provide every course with a line #. I assume that is so they can be easily referenced in court proceedings?
The L# was mainly to key to the table of line annotations in Part Two of the map that also gave the multiple record courses and distances along various of the lines shown.
In the case of the erroneous meanders of the 670 ft. elevation contour located by a prior survey, the L# also provided a way to declutter the map by removing all the bearings and distances along the erroneous meanders to some other part of the map. Those meanders were simply an incorrect location of the 670 ft. NGVD29 contour and held no information other than demonstrating that one particular corner was what I show it to be on the map.
:good: :bad: :good:
LOL
> Gawd Almighty Kent, that's the ugliest North Arrow I've seen since ACAD 3 or so.....
Well, it's true it will never make it into the Country Music Hall of Fame or the nearest tattoo parlor. :>
BTW, just to supply some other details that may be of interest, here is a plot of boundaries of the tract that formed the lakeward part of the land subdivided in both 1950 and 1953. This is a plot of the tract boundaries overlaid on a satellite image taken on a date when the lake level was nominally at elevation 670 ft. So you can see that the corners on the meander line surveyed before 1950 actually do fall very close to the 670 ft. contour, but do a very poor job of capturing its sinuosities.
and here is the same tract overlaid on an aerial photo taken in 1951 after the first subdivision. The lake level was well below 670 when the subdivision was laid out in 1950 and it wasn't until it actually reached a level near the normal full level of 681 that lot sales finally took off.
In 1953 when the resub plat was made, the lake was nearly full and the 670 ft. contour was about eleven feet under the waters of the lake, which explains why the engineer who laid the subdivision out used the edge of the lake at nearly full for his meander line.
Thank you for the station and offset detail. The idea is something I will use from now on when presented with opportunity.
Doh! (slapping my forehead) I think just got it.
Drawing a circle around a filled-in circle is akin to underlying a word in a sentence for emphasis. And (comparatively) I was arguing whether or not you should tell the reader why you underlined a certain word. :-$
Some of us are just slower than others (not mentioning any names)
> Drawing a circle around a filled-in circle is akin to underlying a word in a sentence for emphasis.
Yes, that's the idea. The filled-in circle inside the second circle gets reduced in size a bit so that the overall graphic weight of the double circle symbol is just sufficiently greater than the single circle to readily distinguish it.
