ArcMap Desktop Introduction: Proximity and distance measurement

The Proximity toolset includes:

• Near: For each feature in the input layer, the Near tool finds the nearest feature in same or another layer. Adds attributes such as distance to attributes of input table. Works with points, lines, polygons. Online help.
• Generate Near Table:  A tool similar to above, but creates a new table rather than adding to existing attributes. Online help.
• Point Distance: Works only with point layers. For each point in the input layer, this tool finds the distance to every other point in the same or another point layer.  Results are recorded in a new table. To limit the number of calculations, using a Search Radius is recommended for large datasets because the output table can get really big. Online help.
• Buffer: Creates buffer polygons (a new layer) around input features to a specified distance. An optional dissolve can be performed to combine overlapping buffers. Online help. Also see a more technical discussion of how it works, including a discussion of geodesic buffering used with unprojected geographic coordinate systems (degrees longitude and latitude) and why this might be appropriate.
• Multiple Ring Buffer: Creates multiple buffers at specified distances around the input features (i.e., rings around features). These buffers can optionally be merged and dissolved using the buffer distance values to create non-overlapping buffers. Online help.
• Create Thiessen Polygons: Creates Thiessen polygons (proximal zones or Voronoi cells) from point input features. Any location within a Thiessen polygon is closer to its associated point than to any other point input feature. Online help.

• Select by Location: You can access this dialog from the Selection menu in ArcMap, or using the Select Layer by Location tool.  Adds, updates, or removes a layer's selection based on a spatial relationship to features in another or the same layer.  Relationship examples include Within a Distance, Intersect, Contains, Within, etc.  Online help.| Graphic examples and comparison of relationships.| On using this procedure between features in the same layer.
• Measure Tool:   Click cursor on this tool in the toolbar in ArcMap to turn the cursor into this tool. Allows you to measure distances along a line. areas of polygons, and other basic measurements. Some calculations require your map to use a projected coordinate system. Online help
• Calculate Geometry: Calculates geometric values for features. Adds values to a field in the layer's attribute table (right-click the field to bring up this option).  Includes, depending on the type of feature (points, lines, polygon): Area or Perimeter (polygons), Length (lines) , X- or Y-coordinate of centroid (polygons or lines) or of point, X- or Y-coordinate of start or end point of lines. Online help: Overview | Detailed  You first will probably want to add new blank fields to your table. Online help.