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I am not a geography subject expert and maybe my this comparison make no sense as i don't have enough knowledge (one of the reason to ask this question here).

I have a project where I am doing conversion from unity co-ordinate system to GPS(Lat/Lon) using a library. The conversion working fine but now I got the environment model which is based on SnakeGrid and the same conversion is not accurate. So my question is how is a SnakeGrid based environment different from a latitude and longitude based coordinate system?

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    What do you mean by 'not accurate'? How are you doing the conversion? Which SnakeGrid are you working with? SnakeGrid is a map projection where spherical coordinates (lat/lon) are converted onto a plane (easting/northing), with the added benefit that there is zero map distortion. – JimT May 2 at 7:48
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    Isn't the real question, what is the difference between the unity coordinate system and your snakegrid projection? – nmtoken May 2 at 13:19
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    Unity appears to be 3D Cartesian: XYZ. There's a SnakeGrid converter here for 500 pounds for a year's license. Ask the data provider to convert it for you. – mkennedy May 2 at 18:59
  • @JimT "Not accurate" mean that there is difference between conversion. I am getting the converted value near the point, but not accurate. There is a difference maybe around 30-100 meters etc, – Muhammad Faizan Khan May 9 at 7:50
  • @mkennedy What it should convert? after spending 500 pounds:) – Muhammad Faizan Khan May 9 at 7:51
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SnakeGrid is a type of Snake Projection: a projected coordinate system with grid coordinates in metres Easting/Northing. There are many SnakeGrid coordinate systems available; each one is tailored to a particular project. The most typical project it is used on is long linear engineering projects such as rail infrastructure: for the designed route the Snake projection has virtually zero scale factor distortion at track level within a corridor of approx +/- 20km.

SnakeGrids are usually defined using a '.dat' parameter file. This file will enable conversions between latitude/longitude and SnakeGrid Easting/Northing. The SnakeGrid parameter file is compatible with SnakeGrid enabled software only. This includes:

  • SnakeGrid PointWise. A free desktop tool for converting between SnakeGrid E/N and lat/lon; for points and ASCII text. Requires the correct parameter file.

  • SnakeGrid Projector. A suite of plugins for FME for converting between SnakeGrid E/N and lat/lon for all formats that FME supports. Costs £500 on top of the FME licence costs. Requires the correct parameter file.

The above tools will also convert to/from SnakeGrid and UTM, US State Plane and British National Grid.

There are alternative methods of using Snake Projections using NTv2 transforms which are more generally compatible within geospatial software systems. This may or may not be available depending on which SnakeGrid you are working with.

Suggest going back to your data supplier for further information.

  • Thanks for the response but do i need to convert my project? – Muhammad Faizan Khan May 13 at 15:44
  • Only you can answer that depending on your project requirements. However if you need the SnakeGrid data in lat/lon then yes - you will need to convert it. – JimT Jun 14 at 14:18

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