Question

How to plugin a local projection grid into FME?

  • 17 October 2017
  • 3 replies
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Badge +4

We have a locally customized projection grid in Chile, presented as (X,Y) values in an Excel spreadsheet. How can I plugin the grid into FME to be recognized?


3 replies

Userlevel 2
Badge +12

A good place to start is in this documentation:

About Coordinate Systems

Userlevel 2
Badge +17

Hi @ag,

There are two different ways you can apply the XY transformation grid:

1. The simplest way is to use the grid as input for the RubberSheeter transformer. This transformer will apply the grid adjustments to the source data using an inverse distance weighting. However, this is a specific operation that must be included in all the workspaces doing the reprojection.

2. You can create your own NTv2 grid file that can be used by FME's reprojection. FME uses only the binary version of the NTv2 grid, but the Australian utility GDay can convert from an ascii NTv2 grid to a binary. The GDay documentation also includes the definition for the ascii version of NTv2, so you can create an FME workspace to convert from your Excel file to the ascii file, using the Text File writer. This is much more work, but the result is easier to use within your workspaces.

Badge +4

@DaveAtSafe and @erik_jan, thanks a lot for the information. Very helpful.

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