Polygon Global Snap

Running programmatically

Snaps the features of a polygon layer to another layer (Point, Polyline or Polygon)

Inputs

A polygon layer to be snapped
A snap layer - point, multipoint polyline or polygon
Snap tolerance
Snap options 1 (Snap What)
Snap options 2 (Snap To What)

Outputs

A polygon feature class - the vertices from the source layer will be moved to snap to the features of the Snap Layer (if within the snap tolerance)

Options:

Snap Options 1 (Snap What) - this options lets the user set which elements of the source polygonsto be used for snapping
- Vertices: All the vertices of the source polylines will be used.
- Insert Vertices: This option will get the vertices from the features of the snap layer and will insert new vertices into the source polylines. The new vertices together with the original ones will be used for snapping. This option is slower than the other ones, but gives the best snapping results especially if the polygons to be snapped have much less vertices than the ones from the Snap layer.
Snap Options 2 (Snap To What)
- Vertices: The polygons will be snapped to the nearest vertex of the nearest feature from the Snap layer
- Nearest edge: The polygons will be snapped to the nearest point of the nearest feature from the Snap layer
- Vertices and Edges: If there is a vertex closer than the snap tolerance to the polygons (their elements defined in Options 1) to be snapped, the polygon will snap to it, otherwise it will snap to the nearest edge.

Notes:

The polygons will be cleaned from overlaps. It is recommended that the Clean Polygons function to be used before the Snap Polygons to ensure a better control over the cleaning process.
The snap distance should be in the units of the spatial reference of the input dataset.
The Source and the Reference Datasets can have different spatial references as long as they have the same Geographic Coordinate systems.

Example:

Before Snap

After Snap - Option: Vertices

After Snap - Option: Nearest Edge

After Snap - Option: Vertices and Edges

Running Programmatically

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Parameters

Expression	Explanation
Function Name	SnapPolygons
<input dataset>	A String representing the input layer. Must be of Polygon type.
<Reference Dataset>	A String representing the layer to be used to snap to.
<output dataset>	A String - the full name of the output layer.
<Snap Tolerance>	A Double representing the Snap Tolerance (in the units of the spatial reference of the input dataset.
<Snap What>	Required. A String indicating what parts of the input polygons will be snapped. Possible values: Vertex - the vertices of the source polygons will be snapped. InsertVertex - the vertices from the features of the Reference Dataset will be inserted (if closer to the input dataaset) as new vertices into the source polygon boundaries. The new vertices together with the original ones will be used for snapping. This option is slower than the other ones, but gives the best snapping results especially if the polygons to be snapped have much less vertices than the ones from the Reference Dataset.
<Snap To What>	Required. A String indicating to what parts of the reference geometries the input polygons will try to snap. Possible values: Vertex - the input polygons will be snapped only to the vertices of the geometries from the reference dataset. All - the input polygons will be snapped to the vertices or nearest edge of the geometries from the reference dataset.
{Snap To Z}	Optional. A Boolean indicating whether the input geometries will snap the the Z values of the geometries from the Reference Dataset. Only if both dataset have Z values.

Running the function

ETGWPath used in the table below is the full path to ETGWRun.exe (E.G. "C:\Program Files\ETSpatial Techniques\ETGeo Wizards\ETGWRun.exe")

Language	Syntax
Python	subprocess.call([ETGWPath, "SnapPolygons", "input dataset", "Reference Dataset", "output dataset", "Snap Tolerance", "Snap What", "Snap To What", "Snap To Z"])
.NET using ETGWRun.exe	StartInfo.FileName = ETGWPath StartInfo.Arguments = "SnapPolygons" "input dataset" "Reference Dataset" "output dataset" "Snap Tolerance" "Snap What" "Snap To What" "Snap To Z"
.NET using ETGWOutX.dll	SnapPolygons(input dataset, Reference Dataset, output dataset, Snap Tolerance, Snap What, Snap To What, Snap To Z)
ArcPy	arcpy.SnapPolygons(input dataset, Reference Dataset, "output dataset" , "Snap Tolerance", "Snap What", "Snap To What", "Snap To Z")

Notes:

<> - required parameter
{} - optional parameter
See examples for Python , .NET or ArcPy
The argument separator for StartInfo.Arguments is space. If a string might contain a space, you need to double quote it.

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