Using IDW tool in ArcGIS Desktop

Question

In ArcGIS Desktop 10.7 we have IDW tool, but when you want to work with it you should need two layers such as : Some points and a closed polyline (Boundary) as following:

then using IDW:

but I have a problem. my data is not point is a polyline (Actually is a line joining points of equal rainfall on a map in a given period) as following:

How should I use IDW tool?

This is because I don't have the lines in the first box of IDW tool:

Answer 1

I have found a solution! I think I should convert the feature to points by using "Feature Vertices to Points" Tool in

Data Management Tool > Feature.

why? bcoz in the real world we have discrete data not continues so the polylines are actually some simple lines between some points.

the definition of "isohyetal": is a line joining points of equal rainfall on a map in a given period.

the points are actually are the vertices of the polylines.

as you see the polylines have been converted to some points.

now we should use IDW tool:

to choose "Z value field" in above you should find the rainfall column in the attribute table of the shapefile:

the next step on the IDW window you should click on the Environment Button and then click on the "Raster Analysis" to choose your closed Boundary:

now you see the result:

good luck