 This video will show you how to transform your vector datasets from one coordinate system to another in ArcGIS using the project tool. It's important to note that prior to using the project tool, you should have a dataset that has a known defined coordinate system. If your coordinate system is unknown or not defined correctly, you shouldn't be using the project tool. Moving over to ArcGIS, you can see I've got a project open and I've got a base map loaded. It's the world light gray base map that has both a reference layer and a map layer. I've also got the Vermont State boundary and the National Forest Service trails for the entirety of the United States. By zooming in and clicking on one of the trail segments, we can explore its attributes. We see information on everything from the trail name to its grade, width and other attributes. Down at the very bottom there's a field called shape length. This is the length of each segment. You'll notice in this case the units aren't very meaningful and that has to do with the coordinate system of this particular vector dataset. A different way of exploring the attributes for the trails is to open up the actual attribute table. This allows us to see the attributes for each and every single trail line segment. If we scroll all the way to the end, we once again see that shape length field, which is the length of each trail segment. We can use the statistics tool to look at the overall statistics for all trail segments. These numbers in the attribute table and the summary statistics aren't meaningful at all unless we know the units they are referring to and those units come from the coordinate system being used for the particular dataset. We can access that by right clicking on the dataset, going into the properties, clicking on the source tab and then exploring the spatial reference information. We see that the trails dataset is in a geographic coordinate system, which is no good for making linear measurements. If we want to get the length of all the National Forest System trails in Vermont, we're going to need to get it into a different coordinate system using the project tool. But before we do that, we're going to clip the trails down to the extent of the state of Vermont. We're going to do this by going into our geoprocessing tab and using the clip tool. The clip narrows down the extent of one vector dataset based on the extent of another vector dataset. So in this instance of the run of the clip tool, I'm clipping the National Forest trails down to the Vermont state boundary, creating a new feature class, a new dataset called NFSTrailsVT. Once the clip geoprocessing tools finish running, I've got a new vector dataset in my map called NFSTrailsVT. You can see that that dataset is the National Forest trails clip down to the Vermont boundary. You can also see that the dataset is located within my geodatabase in my ArcGIS Pro project. This is the permanent storage location for that dataset. If we go into its properties, we see that its coordinate system is the same as the source data, which is to say a geographic coordinate system using the NAT83 datum. If we look at the coordinate system for the Vermont state boundary, we see that it's Vermont state plane NAT83 with the unit of meters. This is the standard coordinate system for all mapping within the state of Vermont. So for this project in which our goal is to summarize the length of National Forest trails in Vermont, it makes sense to use the project tool to project the National Forest system trails clip to the state of Vermont from the geographic coordinate system to the Vermont state plane coordinate system. The project tool works by transforming the coordinate system in the input layer and creating a brand new output layer. In this case, I've selected the output coordinate system to match the Vermont state boundary, but I also have the option of going in, browsing, and choosing a coordinate system either from the layers in my project or from the full list of coordinate systems supported by ArcGIS. After the project tool has finished running, you'll see that I've got a new layer in my ArcGIS Pro project called NFS trails VT state plane. This is the National Forest trails in Vermont state plane coordinate system. Going into the properties of that layer and exploring the spatial reference, we see that the project tool did exactly as it was supposed to do. It created a new layer with the Vermont state plane coordinates. Let's explore the attribute table of this projected layer. Scrolling across, we see that we still have that shape length field. This is the length of each and every trail segment that's automatically calculated by ArcGIS. We see the numbers are a lot larger now. They're no longer in decimal degrees, which is a meaningless unit. They're in meters because the coordinate system for our layer is in Vermont state plane at 83 meters. As a result, the summary statistics are also much larger and now in a meaningful unit that we can use to draw conclusions about the length of all National Forest trails within the state of Vermont. Just as we did before, we're going to zoom in and click on one of our trail segments. Scrolling down through the attributes, we see that it has a shape length field, but because this is the projected layer, we see that the linear units are in meters because we projected it to Vermont state plane meters. In this tutorial, we showed you how to use the project tool to transform the coordinate system of a data layer from a geographic coordinate system to a projected coordinate system. In this example, that was necessary because we wanted to measure the length of all trails within the state of Vermont and a geographic coordinate system is not suitable for measurements, so we needed to have our data in a projected coordinate system.