I have a site plan for a development in the City of Pittsburgh. A Note states the following: "...coordinates are referred to the meridian of the Department of City Planning, Pittsburgh, PA, as obtained from unadjusted D C. P traverse points."?ÿ Additional info on the plan: R 336/15, N 117011.89/E 115723.57 and R 336/15, N 116529.68/E 115362.98
The N and E coordinates look like SPC system, however, they convert to somewhere near Cincinnati. Please assist.
I would assume there was some sort of monumentation at points R336/16 and R336/15. If you can't find them, you will have to talk to the DCP.
Or hope @john-hamilton replied to your post.
The N and E coordinates look like SPC system, however, they convert to somewhere near Cincinnati. Please assist.
1951? These would have to be NAD27 based coordinates. I have no idea about Pennsylvania, but in Oregon the '27 and '83 coordinate systems have dramatically different false northings/eastings in their definitions to make the?ÿ coordinates for a given point dramatically different in the 2 systems.
@mark-mayer
But neither NAD27 nor NAD83 SPC in the Pittsburgh area are anywhere close to those numbers. They are about 22.2 miles north and 21.9 east of the coordinate origin. If the coordinates are in Pittsburgh, that puts the origin well inside Pennsylvania so it can't be SPC and has to be a local system.
http://www.briem.com/files/PittsburghGeodeticSurveyHistory.pdf?ÿ
Page 14 (page 20 in pdf reader) of the report gives the geographic coordinates of the grid origin of the 1925 system. It's a fascinating read, filled with editorial comments.
Maybe not very helpful, but it does explain the low numerical values of the given coordinates.
@mathteacher
Thank you. On first read, this document appears to provide the explanation.
@mathteacher
Congratulations on your Google prowess. I made a brief search but didn't pursue it far.
Some crude calculations would put one the points listed in the original post in or north of Allegheny Arsenal Park.?ÿ Is this right??ÿ The calculations came out north of the park, but I'm uncertain what to do about a convergence angle, and the park seems much more likely than the housing development, unless that was also part of the arsenal grounds at the time.
Nice find Math Teacher.?ÿ
The coordinates look like a 100,000 100,000 type of local control.?ÿ
They put lots of effort setting up the original network, if I worked there I would want to tie into it and have it available.
Much like NAD27 it will be a monument controlled system, imperative to have the nearest monuments for any project if you really wish to use it as a basis.?ÿ
?ÿ
@bill93
I took a bit of a different approach and calculated the distance and grid azimuth from the origin to R336/16, roughly 4.4 miles and 43 degrees. Then I just dumbly used that to measure to a point in Google Earth. Far from exact, but it seems to be in or near Highland Park Historic District.
LOL! Nothing like mixing unknown datum with Web Mercator and declaring victory!
I think I found point 15 on a data sheet, but it has been reported as destroyed. No similar data sheet for 16.
KX1471 DESIGNATION - 15
?ÿKX1471* NAD 83(1986) POSITION- 40 29 01. (N) 079 56 58. (W) SCALED
...
KX1471 HISTORY - Date Condition Report By KX1471 HISTORY - UNK MONUMENTED PA6600 KX1471 HISTORY - 1941 GOOD CGS KX1471 HISTORY - 19920401 DESTROYED USGS KX1471 KX1471 STATION DESCRIPTION KX1471 KX1471'DESCRIBED BY COAST AND GEODETIC SURVEY 1941 KX1471'AT PITTSBURGH. KX1471'AT PITTSBURGH, ALLEGHENY COUNTY, ABOUT 3.8 MILES EAST ALONG KX1471'PENN AVENUE AND BUTLER STREET FROM THE PENNSYLVANIA RAILROAD KX1471'STATION, IN THE NORTHEAST CORNER OF THE FOUNDATION OF A BUILDING KX1471'LOCATED AT 5438 BUTLER STREET, AND 10 FEET SOUTH OF THE SOUTH KX1471'CURB. A DEPARTMENT OF PUBLIC WORKS BRONZE DISK, STAMPED 15. KX1471 KX1471 STATION RECOVERY (1992) KX1471 KX1471'RECOVERY NOTE BY US GEOLOGICAL SURVEY 1992 KX1471'SURFACE MARK REPORTED DESTROYED.
?ÿ
The street address is northwest of my crude computation.?ÿ To get nearer, I need to rotate my computation ~5 degrees.?ÿ MathTeacher would need a lot more rotation.
I'm not sure about the "northeast corner", as the streets are not cardinal, and this could be the easternmost corner of a former building.?ÿ Plotting the bearing and distance on Google Earth gets near another street, and if I lived close I would search the building fronts along both sides of that street for a possible disk 15 that C&GS didn't measure.
This seems to be the area in 1944, kind of the upper left-hand corner of the sheet:?ÿ https://digital.library.pitt.edu/islandora/object/pitt%3A081e1944/viewer
Hard to know how things look today and there are lots of assumptions, but the grid seems to fit if you look at sheet 3 https://digital.library.pitt.edu/islandora/object/pitt%3A003e1932/viewer
The address for all of the sheets is: https://digital.library.pitt.edu/islandora/search/dc.title%3A%283%29?f%5B0%5D=RELS_EXT_isMemberOfCollection_uri_ms%3A%22info%5C%3Afedora%5C/pitt%3Acollection.294%22&islandora_solr_search_navigation=0
I used the search field "Title" and the number of the sheet as the search term. PDF page 43 of the Pittsburgh Geodetic Survey History shows the sheet numbers where some of the stations can be found. I used sheet 90 as the starting point and then used the join numbers at the corners and sides to navigate to the sheet that contains the given points.
This is an excellent research site and seeing the time lapse between sheets was amazing. Hope this helps.
?ÿ
?ÿ
?ÿ
Yes, the neighborhood is northeast of Allegheny Arsenal Park, on the other side of Allegheny Cemetery. The plan is attached. My apologies for not sharing this sooner. I was simply trying to decode the coordinates.
?ÿ
Confused again -- I meant search for 16.
Wow!?ÿ That is a fantastic plan to look at.?ÿ I've certainly tried to use worse.?ÿ The Department of City Planning certainly had their standards well thought out or the engineer and surveyors had their corporate drafting standards well thought out.
?ÿ
Kudos to all you sleuths on RPLS!?ÿ ?????ÿ