Hello,
I'm currently working in a big railway project that uses a bespoke GCS.
I was following a forum post that explaining how to create a transformation. In the process the seed file "UserOverrideGeodeticTransformSeed.asc" needed to be altered.
The heading of the file contain the following text:
"# In case of absolute necessity it is possible to override the list or# order of the grid shift files for a specific datum transformation.# This should only be done if no other solution is available.# Bentley Systems would be glad to introduce new files directly# referenced by the built-in system dictionary as part of a refresh to# its software. Contact Bentley system through the normal support channel."
As you can imagine this new GCS is a big headache with all the legacy data.
Is there anyone in the position to help?
Thank you in advance for your time.
Regards,
Eurico
We are aware of the dhp11 SnakeGrid transformer http://www.dhp11.com/snakegrid.html. The project opted to use FME https://www.safe.com/fme/key-capabilities/data-transformation/.
None of this solutions work seamlessly. There is a few pros and cons on each software, some will break(drop) all elements or not process .pod files… and so on.
Both solutions have a patchy feeling, none is quite there, hence my quest for a better integrated solution. Besides we already use a software with the capabilities. For all sort of reasons if we have to buy another software, in the end of the day we are not being very efficient.
Eurico Inacio said:
None of those solutions work seamlessly
It looks like the missing component is a custom GCS for MicroStation that corresponds to the data translated by FME. Can FME generate that GCS?
If FME can't provide that information, you could commission someone to write a GCS generator for you. The API for MicroStation CONNECT includes GCS support.
Regards, Jon Summers LA Solutions
Jon,
Thank you for your help and time!
According to the replies, you are working with the HS2 Survey Grid (SnakeGrid).
The HS2 SnakeGrid (phase 1+2a) can now be defined within the Microstation GCS library using an NTv2 transform + Transverse Mercator projection. It will be available in Microstation update 13 however will require manual installation of the transformation files. MS CE Update 14 will have the files distributed.
Two GCS will be available: HS2_Snake_2002 and HS2_Snake_2015. These are essentially the same GCS - the difference is the transformation used for conversions into other GCS:
Note that the HS2TN02 transform is equivalent to using the HS2P1+14 SnakeGrid parameter file. If converting into lat/lon using HS2TN02/HS2P1+14 then these coordinates are only compatible for use with the legacy OS Active Network (OS Net v2001).
Hi Jim,
Thank you for your help on this subject.
I'm eager to try this new solution.