Hi!I am trying to transform a dxf-file from SWEREF99 13 30 to SWEREF99 TM. I simply set the coordinatesytem to the one I want in the writer and executes. The result is a file that is more than ten times as big as the original. Why is this?Thankyou.

Change coordinatesystem in a dxf?

Hi @tobiasp, can you try using the FME's quick translator?

Hi! The new file still comes out much larger. I just dont understand why changing the coordinatesystem will make the filesize go from ~10 mb to more than 200? Is this normal? : )

Regarding the large file, there is a parameter that "Explode Blocks into Entities"

This would increase the file size.

Hi Tobias,

DXF files are basic text files, so have you had a look inside them with a text editor ? Maybe the answer is obvious just from looking at them ?

Cheers

Hi @tobiasp,

When I look at the definitions of both coordinate systems, they are quite similar. The only differences between them are the central meridian ("13 30" has 13.5 while "TM" has 15) and the scale factor. "SWEREF99 13 30" has a scale factor of 1 (so no scaling occurs), whereas "TM" has a scale factor of 0.9996. This might be the cause of your "exploding" file size: all coordinates that were integers before become doubles now and all floating point coordinates that were rounded to (let's say) 3 decimals might end up with a lot more.

What you could try (to see if the file size gets any smaller) is to make a workspace with a DXF reader, followed by a Reprojector (or CsmapReprojector if the file contains Z values) transformer set to convert to "SWEREF99 TM" and then a CoordinateRounder where you round to 3 decimals for example (if mm resolution is good enough). Finally, add a DXF writer and set the Coordinate System to <Not Set>, so it will take the one set by the Reprojector.

Hope this helps!

Hi @tobiasp,

When I look at the definitions of both coordinate systems, they are quite similar. The only differences between them are the central meridian ("13 30" has 13.5 while "TM" has 15) and the scale factor. "SWEREF99 13 30" has a scale factor of 1 (so no scaling occurs), whereas "TM" has a scale factor of 0.9996. This might be the cause of your "exploding" file size: all coordinates that were integers before become doubles now and all floating point coordinates that were rounded to (let's say) 3 decimals might end up with a lot more.

What you could try (to see if the file size gets any smaller) is to make a workspace with a DXF reader, followed by a Reprojector (or CsmapReprojector if the file contains Z values) transformer set to convert to "SWEREF99 TM" and then a CoordinateRounder where you round to 3 decimals for example (if mm resolution is good enough). Finally, add a DXF writer and set the Coordinate System to <Not Set>, so it will take the one set by the Reprojector.

Hope this helps!

And also try what @mark_1spatial suggests (uncheck the reader parameter "Explode Blocks into Entities"). Although that setting should be switched off by default when doing a DXF-DXF Quick Translation. But when you make a workspace, it's switched on.

Regarding the large file, there is a parameter that "Explode Blocks into Entities"

This would increase the file size.

I knew this problem could be solved by unchecking a box somewhere! Thankyou very much!

Hi @tobiasp,

When I look at the definitions of both coordinate systems, they are quite similar. The only differences between them are the central meridian ("13 30" has 13.5 while "TM" has 15) and the scale factor. "SWEREF99 13 30" has a scale factor of 1 (so no scaling occurs), whereas "TM" has a scale factor of 0.9996. This might be the cause of your "exploding" file size: all coordinates that were integers before become doubles now and all floating point coordinates that were rounded to (let's say) 3 decimals might end up with a lot more.

What you could try (to see if the file size gets any smaller) is to make a workspace with a DXF reader, followed by a Reprojector (or CsmapReprojector if the file contains Z values) transformer set to convert to "SWEREF99 TM" and then a CoordinateRounder where you round to 3 decimals for example (if mm resolution is good enough). Finally, add a DXF writer and set the Coordinate System to <Not Set>, so it will take the one set by the Reprojector.

Hope this helps!

Hi! Interesting theory, I will have a look at this even if my problem was solved by changing the parameter. Thanks for your time!

Hi @tobiasp,

When I look at the definitions of both coordinate systems, they are quite similar. The only differences between them are the central meridian ("13 30" has 13.5 while "TM" has 15) and the scale factor. "SWEREF99 13 30" has a scale factor of 1 (so no scaling occurs), whereas "TM" has a scale factor of 0.9996. This might be the cause of your "exploding" file size: all coordinates that were integers before become doubles now and all floating point coordinates that were rounded to (let's say) 3 decimals might end up with a lot more.

What you could try (to see if the file size gets any smaller) is to make a workspace with a DXF reader, followed by a Reprojector (or CsmapReprojector if the file contains Z values) transformer set to convert to "SWEREF99 TM" and then a CoordinateRounder where you round to 3 decimals for example (if mm resolution is good enough). Finally, add a DXF writer and set the Coordinate System to <Not Set>, so it will take the one set by the Reprojector.

Hope this helps!

You are right, the file does come out smaller, but still a lot bigger than the original file.

Yeah, I already expected that the file wouldn't be that much smaller. Mark's suggestion makes the biggest difference!

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