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Unrecognized spatial reference systems (SRS) and rights-of-way

In some cases, the automatic scan may fail to fill in the coordinate system and/or the convex envelope. To identify the data concerned, nothing could be simpler:

As the technology used is FME, we need to ensure that the projections are entered in such a way as to be correctly read by theETL.

Case 1 (majority): one right-of-way, no SRS

In most cases, the problem is that FME does not recognize the coordinate system. This does not mean that the system could not be read and used by FME. In short, FME uses the system definition, but does not recognize it.

A right-of-way, no SRS

To correct this problem, you need to tell FME how to recognize this system. There are two possible scenarios:

The system is referenced with an EPSG code

Go to the Reproject/Exceptions folder (in the FME installation directory), and edit the file corresponding to the format used. Then find the paragraph concerning the country of the coordinate system. Then, as for systems already present in the document, add a new line for the system to be added.

Editing the esriwkt.db file

Examples

Lambert93 coordinate system (EPSG 2154) for ESRI formats (Shapefile, Geodatabases...) is not recognized:

  1. Open esriwkt.db,
  2. Find the French paragraph,
  3. By default, several definitions already exist for the Lambert93 system;
  4. Add your definition by copying it from the .prj file.

Tip: if you don't have a .prj file (stored in geodatabases, for example), you can easily create one by right-clicking/save as...

The RGF93 / CC42 (EPSG 3942) coordinate system for the Oracle format is not available recognized :

  1. Open the oracle.db document,
  2. Find the French paragraph,
  3. Add the following line: ORACLE|RGF93.CC42|3942.

The system is not referenced and has no EPSG code

The SRS will not be shown, but the convex envelope will still be drawn.

Case 2: neither right-of-way nor SRS

If the plug has no right-of-way, it means that reprojection could not be carried out, which means that FME does not have the original system.

No SRS, no right of way

This can happen with data formats that don't correctly handle coordinate systems, as is the case with CAD files for example.

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