Hello all,
I've got a lot of parcel data sets I need to reproject, and I want to use the CSMapReprojector as this allows the use of ellipsoid heights, however I've just noticed that the tool is converting my true curves to densified lines. Is there any way around this? If I can't get it to work, then I won't be able to use the CSMR.
Thank you!
Could it be that the curves are defined by centerpoint and radius (ArcByCenterPoint)? You can verify this by looking at the geometry definition in e.g. the Inspector.
If so, the curves cannot always be preserved if the reprojection would deform the circle, thereby making it impossible to retain a strict curve definition.
More info about how FME handles arcs here:
http://docs.safe.com/fme/2018.1/html/FME_Desktop_Documentation/FME_Workbench/!FME_Geometry/Arcs.htm
Generally speaking, it's easier to retain the curve if they're defined by three points (ArcBy3Points) before reprojecting.
Hello @david_r,
Thank you for replying. My arcs are all 'Arc By Center Point With Ends', calculated that way from the original parcel definition. This would seem to be a derivation of the definition you're talking about, so subject to deformation. Unfortunately as these are legal parcels, I'm not sure I can validly convert them to ArcBy3Points without destroying the original traverses.
Sounds like I won't be able to use CSMR? Bother. Strangely, I reprojected the dataset using ESRI ArcMap, and the curves were preserved. I guess this will have to be my work around, although it takes much longer than FME!
By definition, an arc by 3 points can be 100% identical to any arc by center point with ends, but unfortunately it's not trivial converting arcs from one type of another with FME: you'll have to decompose all the aggregates, paths and polygons into their individual path segments, check for arcs and convert, then reconstruct all the geometries again.
I'm not sure how ArcGIS handles this, but is it maybe possible that it automatically converts the arcs to "by 3 points" when reprojecting? You could test this by viewing the result with FME.
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