Geoprogressing Tools

The Buffer Tool

The Buffer Tool is a proximity function. When you use this geoprocessing tool, it creates a polygon at a set distance surrounding the feature(s). A buffer is a polygon or collection of cells that are within a specified proximity of a set of features.

buffer The buffer tool is a proximity function that sets a fixed or variable distance surrounding the feature(s).

Add a point, line or polygon feature.
Set a buffer distance.

The Clip Tool

A clip is an overlay tool that cuts out an input layer with the extent of a defined feature boundary. The result of this tool is a new clipped output layer.

clip The Clip Tool is a geoprocessing tool that extracts the input feature based on the extent of another polygon feature.

Add the feature to be clipped.
Set the extent to be clipped to using a polygon feature.

global horizontal irradiance (GHI)

The Merge Tool

The merge geoprocessing tool combines data sets that are the same data type (points, lines or polygons). When you run the merge tool, the resulting data will be merged into one.

merge The Merge Tool combines input features from multiple input sources. It creates a single, new, output feature class.

Add the features to be combined. Make sure they are the same data type
Run the tool. Voila, you have all the features in a single file.

The Dissolve Tool

The Dissolve Tool unifies boundaries based on common attribute values.

The dissolve tool aggregates neighboring boundaries based on common attribute values.

The Dissolve Tool merges neighboring boundaries based on common attribute values.

The Intersect Tool

The only exception is that attributes from all the data sets that overlap each other are preserved in the final data set.

The Intersect Tool performs a geometric overlap. All features that overlap in all layers will be part of the output feature class – attributes preserved.

Add multiple inputs. Different data types (points, lines and polygons) are accepted.
When features overlap each other, they will be in the output.

The Union Tool

The Union tool spatially combines two data layers. It preserves features from both layers at the same extents.

union The Union Tool maintains all input features boundaries and attributes when it is written to the output feature class.

Add features you want to union
Run the tool. More records will be generated, especially when there’s more overlaps.

The Erase (Difference) Tool

The input layer is what will be erased. The erase feature determines what will be erased.

erase The Erase Tool removes features that overlap the erase features. This geoprocessing tool maintains portions of input features falling outside the erase features extent.

Add features you want to erase
Select the features that you want to erase with.

Geospatial Analysis

Single Layer Analysis

Buffering

Constant width buffers require users to input a value by which features are buffered, such as is seen in the examples in the preceding paragraph.
Variable width buffers, on the other hand, call on a premade buffer field within the attribute table to determine the buffer width for each specific feature in the dataset.
Multiple ring buffers can be made such that a series of concentric buffer zones (much like an archery target) are created around the originating feature at user-specified distances.
Doughnut buffer and Setback buffer.In the case of polygon layers, buffers can be created that include the originating polygon feature as part of the buffer or they be created as a doughnut buffer that excludes the input polygon area. Setback buffers are similar to doughnut buffers; however, they only buffer the area inside of the polygon boundary.

different types Additional Buffer Options around Red Features: (a) Variable Width Buffers, (b) Multiple Ring Buffers, (c) Doughnut Buffer, (d) Setback Buffer, (e) Nondissolved Buffer, (f) Dissolved Buffer

Geoprocessing Operations

Single Layer Geoprocessing Functions

Multiple Layer Analysis

Overlay Operations

The point-in-polygon overlay operation requires a point input layer and a polygon overlay layer. Upon performing this operation, a new output point layer is returned that includes all the points that occur within the spatial extent of the overlay.
The polygon-on-point overlay operation is the opposite of the point-in-polygon operation. In this case, the polygon layer is the input, while the point layer is the overlay.
A line-on-line overlay operation requires line features for both the input and overlay layer. The output from this operation is a point or points located precisely at the intersection(s) of the two linear datasets.
The line-in-polygon overlay operation is similar to the point-in-polygon overlay, with that obvious exception that a line input layer is used instead of a point input layer.
The polygon-on-line overlay operation is the opposite of the line-in-polygon operation. In this case, the polygon layer is the input, while the line layer is the overlay.
The polygon-in-polygon overlay operation employs a polygon input and a polygon overlay. This is the most commonly used overlay operation.
Other methods
Spatial Join

A spatial join is a hybrid between an attribute operation and a vector overlay operation.Unlike the attribute operation, a spatial join determines which fields from a source layer’s attribute table are appended to the destination layer’s attribute table based on the relative locations of selected features.
When employing the proximity (or “nearest”) option, a record for each feature in the source layer’s attribute table is appended to the closest given feature in the destination layer’s attribute table. The proximity option will typically add a numerical field to the destination layer attribute table, called “Distance,” within which the measured distance between the source and destination feature is placed.
When using the containment (or “inside”) option, a record for each feature in the polygon source layer’s attribute table is appended to the record in the destination layer’s attribute table that it contains. If a destination layer feature (point, line, or polygon) is not completely contained within a source polygon, no value will be appended.
Overlay Errors

Although overlays are one of the most important tools in a GIS analyst’s toolbox, there are some problems that can arise when using this methodology.
Slivers are a common error produced when two slightly misaligned vector layers are overlain.
Error propagation arises when inaccuracies are present in the original input and overlay layers and are propagated through to the output layer.