Creating random points only within multipart polygon and none outside using ArcMap

Question

I am currently using a shapefile consisting of an area smaller than the entire study boundary ie. I want this to to be my overall study area. I used a raster to polygon tool and converted it to a shapefile and used the Dissolve tool to create a multipart polygon.

Now when I am creating random points and specify the constraining feature class, it is creating random points outside the polygons I possess as well. Attached is a screenshot of random points all over, instead of just within the polygons.

Answer 1

Another option is the Sampling Design Tool, which gives you the option of how to place random points...inside any feature or by specifying the number of random points in features with specific attributes.

Answer 2

I post this answer here because QGIS is free software and my approach is very easy to use. I tried out it with the multi part shapefile of next image where, at its attributes table, I created the field n_points with the number of random points to generate (1000).

In the Menu Bar of QGIS, Vector -> Research Tools -> Random Points, to get the Random Points Tool:

it was marked "Use value from input field" and selected n_points as input field. It was also selected the name of output shapefile. After OK, I got the following result where 1000 random points are only within a multi-part polygon and none outside.

Answer 3

What you are asking is a very common process. As you are looking for a tool for ArcGIS to automate this process your first "port of call" should always be the ArcGIS Code Sharing website, a 2 second search on that threw up the Generate Random Points tool.

Now I've not personally used this but it may behave oddly because you dissolved your data into a multipart. So are you wanting to sample each part or each constituent polygon? If it is the polygons you want to sample a set number of times the I would recommend you exploded them out into single parts again and feed that into this tool.