I'm fairly new to ArcGIS and I have never used the interpolation tools before this project. I am generating an interpolated surface to show vine impacts on trees within a nature preserve using data collected in the field. When using IDW, the interpolated surface stops at the furthest points in my shapefile, and does not fill the entire preserve, leaving the corners empty. I can clip the surface to the boundary but the corners of the preserve are still not included in the interpolated surface. I thought perhaps this was the way this tool is meant to function but I did some reading and found maps where the surface extends past the points, so I figure there must be some way to do this with my data as well. My question is, how do I generate an interpolated surface that covers the entirety of my study area? I've posted a jpeg of my current map below. Any help would be greatly appreciated!