Invert polygon

[PeterGardner]

I have a polygon of a geographical area. I want to shade the area outside it. Despite having read various posts on the subject I can't work out how to do this in ArcGIS Pro. I am a relative beginner on the ArcGIS Pro so any 'straight forward' explanation would be appreciated.

[DuncanHornby]

Outside goes to where...infinity. How do you map the edge infinity? You can't! Create a new polygon layer , create a rectangle that encompasses everywhere you are going to map. Then use the editor clip tool to clip out your polygon, the resulting polygon you can shade. Never clipped out a hole from a polygon then read the help file here.

[PeterGardner]

Duncan
Many thanks for your helpful response. I have read the help file for clipping, but am still unclear of the settings. If I click "clip all editable features" and Discard (Remainder) which says it should just delete the areas that intersect, which should be right, but it deletes everything. If I don't select "clip all editable features" it is stuck Selecting Features for the last four and a half hours.  It is frustrating for something I can do in 15 seconds in QGIS.

[DuncanHornby]

Sounds like you have not got the sequence right, here is a video to show you how to create a polygon with a hole which you can then use to shade/mask data outside the polygon of interest.

Click on it to enlarge.

[PeterGardner]

Duncan
Many thanks. Each time I clip it deletes the duplicated area out of the original map rather than out of the rectangle. I am trying to colour the sea around Britain, each database I can find of the sea is not precise enough for my purposes so I am using the Ordnance Survey Boundary Line data which runs down to the low water mark. 

Thanks
Peter

[DuncanHornby · Accepted solution]

I can take a polygon layer representing the UK and clip out the UK from a bounding rectangle, as shown in my video, so not sure what you are doing wrong because it can be done.  If you are processing whole layers, because until you showed your UK example you had not actually told anyone that this was the case which seems like quite an important bit of information to miss out... then consider using the ERASE geoprocessing tool instead.

[PeterGardner]

Duncan
Many thanks, the erase tool works really well. I apologise for not being sufficiently clear at the beginning, I thought "polygon of a geographical area" was a sufficient description, the problem may have been coming from QGIS where doing this is described as "Inverted Polygons". Many thanks for your patience getting me to the solution.

[jcarlson]

Go into the map properties, there's a tab for clipping. Select "clip to an outline", then pick your layer. That's it!

Or did you mean something else by "shade", like fading the other areas?

[PeterGardner]

Josh
Thanks for your response. What I want to do is colour the area outside. If I am not mistaking what your example does it leaves the area outside blank. 

[jcarlson]

Well, it would be incredibly hacky, but what about duplicating your map layers, excluding some from the clip, and changing the display? Here's imagery added twice, but the non-clipped version has 50% transparency.

It's a far cry from Q's "inverted polygon" symbology style, that's for sure.

An opposite strategy would be getting a global-coverage layer like Jon Nelson's global blank basemap, then using layer masking to mask out the area of interest.