How to clear\define the coordinate system of a particular layer in catalog of ArcPro?

[RoryAshton]

I hope @JamalNUMAN found a solution to this...

I'm using ArcMap 10.6 for university projects and after importing data to explore, I want to remove it and go back to the "Blank Slate" with Unknown Units to then explore other data.

Currently, I have to open a new blank template or seeming risk my next imported data be projected onto the (now) default coordinates of the data that has been removed?

any help is really appreciated! I'm still very inexperienced with the software 😑

[BojanŠavrič]

You can always change the coordinate system of your map. In your ArcMap project, go to Layers -> Properties. In Data Frame Properties window, open Coordinate System tab, navigate to Layers folder and select a coordinate system of the layer you wish to explore.

If you still wish to clear a coordinate system of your Data Frame, under "Coordinate System" tab, go to "Add Coordinate System" and select "Clear." "Apply" or "OK."

Please note that if your Data Frame does not have specified a coordinate system, a lot of things might not work, and some tools might produce incorrect results. Clearing a coordinate system form a Data Frame can be useful, but it is also dangerous. 

[RoryAshton]

Thanks, @BojanŠavrič.

So my understanding is that when I clear the Data Frame's coordinate system, the units shown in the bottom right of the window (below) are just a "relic" of the previous data and have no impact on any importing and defining the coordinates of subsequent shapefiles/geodatabases.

(i.e. adding new data and then defining its coordinate system will not be impacted by a previously clearing of the Data Frame's coordinate system)

Thanks again for the speedy reply! Really trying to avoid creating large uni projects on maps that have the wrong foundational structure.

[BojanŠavrič]

When you clear Data Frame's coordinate system, ArcMap reads any data as it would be provided in Map's units, defined in Data Frame Properties -> General. It will completely ignore data's coordinate systems and there will be no projection on-the-fly. The same data, one in meters and one in US Feet will be offset for a lot and data in geographic coordinates will be very very small, located in null-island. Basically nothing will line up.

When you add more data after clearing a coordinate system, that will overwrite your previous selection and your Data Frame's coordinate system will be the one of your new data. Since Define Projection tool does not add new data, I assume this tool does not overwrite the cleared coordinate system, but Project tool most likely does. I suggest you add all your data you wish to explore before clearing a coordinate system.

As I mentioned above, clearing a coordinate system from your map is risky and you really need to know what you are doing. Tools do not work properly and it might lead to data corruption. Therefore, ArcMap overwrites cleared coordinate system every time it can.

[LindaWilliams1]

When you add items from the Catalog pane, you can right-click and select Add to New Map. The new item will open in the new Map (named Map1, Map2, ...) view with its own coordinate system. If you add the item to the current map its projection will be transformed on the fly. You can then remove the original map view using the Catalog pane or View to keep your project tidy.

[RoryAshton]

Thanks, @LindaWilliams1, I think that might be for ArcPro? I can't seem to find it on ArcMap 10.6 (as below)

[JamalNUMAN]

What we wanted here is to have the “clear” option as it’s used to be in ArcMap.

The idea is here:

How to clear\define the coordinate system of a particular layer in catalog of ArcPro?

[JamalNUMAN]

Correct. It's for Pro

[JamalNUMAN]

Thank you BojanŠavrič for the input

At the end of the day, the “clear” tool needs to be available for those who prefer to use it. It’s not compulsory for users who like to work without it. This way, we have them both happy!