How to project the basemap in BNG?

[GladBiotel]

Hello everyone, for a research project, I need to work with the British National Grid projection but the basemap is in WGS1984, how can I reproject the basemap in BNG ? Thank you very much

[JayantaPoddar]

Are you referring to an Esri Basemap (Esri Basemaps are in Web Mercator)? You can't reproject an Esri basemap.

But, if you are working on ArcGIS Desktop, you could transform the basemap on the fly to a desired Projection system. You could follow these steps.

1. Open a blank Map Document.

2. Add a data (with BNG projection) to the data-frame/ or change the Projection System to BNG from Data-Frame Properties.

3. Add the desired Basemap to ArcMap.

If prompted, choose an appropriate Transformation method.

In case it is a different basemap, please provide further details about it. Also let me know if you are working on a different platform.

[shan_sarkar]

Glad,

1. Are you working with ArcGIS Desktop or consuming the service in some application?
2. Are you referring the ArcGIS Online basemaps?

AGOL basemaps are available with WGS 1984 Web Mercator (Auxiliary Sphere) WKID 102100 and this available as read only for all user globally. Hence we cannot permanently project the basemaps to another spatial reference, however, you can change the projection of the basemap by changing on-the-fly projection ArcMap data frame properties (If viewed in ArcGIS Desktop) or can be changed from code side (is it is being consumed in some application)

I hope this helps!

~Shan

[GladBiotel]

Thank you to you 2, it works almost but my points with the basemap in BNG are now located in the sea instead of being located above London.

With the WGS1984 projection system, the points are well located. So it is not a problem of coordinates.

Someone knows why ?

 

[JayantaPoddar]

Could you zip and attach a sample of the point Feature, so that we could check? It must be using BNG projection system I guess.

[GladBiotel]

Thank you very much for your help.

Here are my points in a Google Doc.

Feuille de calcul sans titre - Google Sheets 

[GladBiotel]

The points coordinates were obtained with a GPS Garmin.

[GladBiotel]

And sorry, maybe it is a silly question but since monday, I can't find a solution !

[JayantaPoddar · Accepted solution]

I feel the Lat./Lon. values in the excel sheet, are based on GCS_WGS_1984.

Follow these steps and let me know if the points are overlaying correctly or not.

1. Import XY data tables to ArcMap and convert the data to a shapefile . While importing, use "GCS_WGS_1984" as the spatial reference.

2. If required, reproject the above point shapefile to British National Grid using Project tool.

[GladBiotel]

Thank you very much, It worked, I solved my problem !