Simplify Your Workflow with the Spatial Join Tool
One of the benefits of GIS is the ability to summarize relationships between different types of data.
In this example, a relationship is determined between students and study sectors. Students being a point layer and study sectors being a polygon layer. Determining the number of students within each sector is easy to do by simply counting the visible points for each area. The is not always correct as some points can fall on top of each other. You can use the select by location tool to find the exact number of student within each sector, but this can become time consuming if you have a lot of areas to cover. The solution to this problem is the spatial join tool. This tool determines the spatial relationship between the polygons and points. A point count for each polygon is created and placed in the attribute table.
Here is a demonstration video:
Note: Videos are broadcast through youtube.com. Some browsers may block this content.
Download the video to your computer: ArcMap Spatial Join Tool
Buffering Features in ArcGIS
Buffering is a useful technique in GIS. It is referred to as a proximity tool in ArcToolbox. It can be applied to points, polylines, and polygons. Some valuable uses include: Right-of-ways, Tree diameters, Sex Offender Exclusion Zones, Study Areas, Impervious Surfaces from a Centerline, Evacuation Zone of Weather Events, etc.
To perform a single distance buffer:
1. Open the Buffer Tool – ArcToolbox >Proximity >Buffer
2. Fill Inputs
- Input Features (Points, Polylines, Polygons)
- Output Feature Class
- Linear Unit (Distance of Buffer) This can also come from a attribute field value.
The remaining entries are optional.
The new output layer from the buffer will be added to the map (circles around red dots).
To perform a multiple distance buffer:
1. Open the Multiple Ring Buffer Tool – ArcToolbox >Proximity >Multiple Ring Buffer
2. Fill Inputs
- Input Features (Points, Polylines, Polygons)
- Output Feature Class
- Enter each buffer distance.
The remaining entries are optional.
The new output layer from the buffer will be added to the map. Notice that I have used the dissolve option. This causes the buffer rings to dissolve based up distance.
