Basemap does not have a valid spatial reference

Question

In ArcGIS Field Maps 24.1.3, I am unable to switch the basemap, despite both the map and basemap sharing the same spatial reference. When attempting to switch, I receive the following error message:
"The basemap does not have a valid spatial reference."

JonathanLebowitz · Answer

Hello. ArcGIS Field Maps will not recognize a coordinate system that is missing a WKID (i.e., authority is set to custom).

JavierML · Answer

Hi @PHATHEKATENGIMFENE ,

sorry for not answering on the weekend.

I see something strange in your screenshots. Your projected coordinate system looks as if it was "Custom". Normally, the projected coordinated system has a defined name, ID and Authority (normally EPSG). Yours doesn't.

It isn't my area of expertise, but I would guess that, after an update or transfering the layer too many times, the Coordinated System is not correctly recognised anymore. Could you try the following:

* Use the project tool to create a new layer with a valid Coordinated Sytem (you could try EPSG:3395, EPSG:4326, EPSG:4258,EPSG:3857 or even the 4148 you currently have)
(WGS 1984 World Mercator) and then upload the layers to Field Maps. You can even try and converting it once again into 
* If you can't reproject, use the tool Define Projection to set the Coordinating System to EPSG:4148 and then try to upload it.

Tell me if it worked or not at the end

2026-03-02_11h45_58.png

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PHATHEKATENGIMFENE · Answer

@JavierML   The basemap is a custom basemap and the layers are using WGS_1984_Transverse_Mercator.

layer.png

basemap.png

NICOSIAVISUM_BMODEL2010_countlocation.zip

vista_nicosia_nodes.zip