[MUSIC]
Welcome back, everyone.
In this lesson, we're going to discuss my favorite tool in GIS,
the Spatial Join tool, and I'm going to show you how to use it
to attach data from one data layer to another by its location in space.
The Spatial Join tool is the proverbial Swiss Army knife of GIS.
I feel like you can make it do anything that you need it to do and that any sort
of question or tool that you might use, any of the many capable tools in our
toolbox for, you could probably make into a problem that Spatial Join can solve.
I think this so much that my coworkers kind of joke that I'm the Spatial Join
guy because whenever somebody comes into our office and asks for help with a GIS
problem, I'll say, well yeah you know you could probably do that with
a Spatial Join, and they're often times coming up with a more appropriate tool.
If you have one geoprocessing tool that you remember and
know how to use, I think Spatial Join should be it because it's so
capable of helping you in all sorts of situations.
To understand how a Spatial Join works,
I think it helps to understand what a standard Table Join is.
And a standard Table Join takes two data tables and brings them together and
attaches the attributes of one to another when they share a value in a common field.
So maybe they both have the same field but one has it in reference to the other table
so when you bring them together it says, well, do they both have the value five
in this field in one table, in this field in the other table?
Yes, okay then, attach all of the attributes in the record for
the second table to that record in the first table.
If that explanation doesn't make sense for you, just note that we are taking
data from one data table in specifically records from one data table and
appending it to the record from another data table based on some relationship.
And it can be an attribute relationship or
it can be a spatial relationship, like our Spatial Join tool.
Joins in general are incredibly powerful and
usually require some sort of sophisticated database management system to run them,
but Spatial Joins in particular are a really unique feature of as GIS,
a spatially aware database system of some sort.
I want to just give you one more comparison to help you understand what
we're going to do with the Spatial Join tool.
Remember we did this by location tool and we selected
features where they shared some sort of relationship to another set of features?
Well, we're using the same document here.
And what we're going to do with Spatial Join is basically the same thing.
Except for instead of selecting the features, we're going to take the features
that have that relationship and append attributes from one to the other.