Tiler

Categories

Geometries

Related Transformers

2DGridAccumulator

2DGridCreator

RasterTiler

WebMapTiler

Splits input features into a series of tiles by specifying either tile size (in ground units) or total number of tiles.  

Jump to Configuration

Typical Uses

  • Tiling data for storage or processing efficiency

  • Tiling data to match the extents of other datasets to enable group processing

How does it work?

The Tiler accepts features with most types of geometry, including vector, raster, and point cloud. 2D and 3D features are supported, with the exception of surfaces and solids. The input features are divided into a series of rectangular tiles, according to parameter selections.

The extent of each tile may be described by:

  • Dimensions in Ground Units - where the height and width of the tiles are specified explicitly in the ground units of the features’ coordinate system, or

  • Number of Tiles - where the bounding box encompassing all features is divided by the specified number of columns and rows.

Features receive Row and Column number attributes identifying the tile they fall within. Rows and columns are numbered from zero (0) and the numbering may start in any corner.

Features are split where they cross tile boundaries. Elements that fall on tile borders may be duplicated in each tile.

Seed coordinates can be used to control tile position when Define Tiles By is Dimensions in Ground Units.

3D features are tiled as they overlay the 2D tiles. Where they are split, z values may be interpolated in a variety of ways. Measures may also be interpolated where required.

RasterTiler or Tiler?

The RasterTiler also tiles rasters, and may be appropriate if you wish to tile based on number of cells (pixels) per tile. This table compares the two:

  Tiler RasterTiler

Tiling extents

Cumulative over all features

Single feature

Type of data accepted

All types except surfaces and solids

Raster only

Tile size units

Ground coordinates

Pixel coordinates

Tile row numbering (0, 1,...)

Selectable

Top to bottom

Supports forcing equal-size tiles

No

Yes

Supports raster index attribute

No

Yes

Supports number of horizontal/vertical tiles attribute

No

Yes

Examples

In this example, we have a set of neighborhood polygons and want to divide them into four tiles.

Note the shape of the selected neighborhood.

The features are routed into a Tiler.

In the parameters dialog, Define Tiles By is Number of Tiles, and Columns and Rows are both set to 2.

Note that the defaults have column and row numbering starting from the lower left corner, with numbers added to new _row and _column attributes.

To better illustrate the tiling, the features are assigned colors according to their column and row numbers with a FeatureColorSetter.

The output features have been tiled, receiving row and column numbers. Features that cross a tile boundary, such as the neighborhood selected above, are split. Both parts keep their original attributes and receive different row and/or column numbers as appropriate.

In this example, we will tile a set of transit line features using a specific tile size. We want the resulting tiles to align with a separately-generated grid. Seed coordinates will be used to control the position.

Note that the features are in a UTM83-10 coordinate system, with ground units in meters.

The features are routed into a Tiler.

In the parameters dialog, Define Tiles By is Dimensions in Ground Units. Both the Width and Height are set to 1000 meters.

The Seed Coordinates are also set to 1000, which ensures the tile corners are placed predictably at coordinates that are multiples of 1000, rather than starting wherever the extents of the features fall.

To better illustrate the tiling, the features are assigned colors according to their column and row numbers with a FeatureColorSetter.

The output features have been tiled, receiving row and column numbers.

The tiled features align spatially with a grid generated separately with a 2DGridCreator, using a 1000-meter interval over a larger area than the transit lines’ extents.

Note the Min and Max Extents values for the grid cell - whole numbers, multiples of 1000. The tile boundaries fall on the same coordinates.

Usage Notes

  • Features in a latitude/longitude coordinate system may need to be reprojected prior to tiling. Consider using the Reprojector or other reprojection transformers. For temporary reprojection for defined tile size, the CommonLocalReprojector may be useful.

  • The Tiler does not create grid. For grid, see the 2DGridAccumulator or 2DGridCreator.

Creating Boxes and Rectangles

Creating rectangular geometry is a common task. These transformers do so in a variety of ways.

Transformer

Function

Creator

Creates one or more new features with box geometry of a specific size and position (when Geometry Object is Box).

2DBoxReplacer

Replaces an existing feature’s geometry with a box of a specific size and position.

BoundingBoxAccumulator

Creates one rectangle that encompasses all features received.

BoundingBoxReplacer

Individually replaces the geometry of each feature with a rectangle that covers its extents.

RasterExtentsCoercer

Individually replaces the geometry of each raster feature with a rectangle that covers its extents (with various Extents Type options).

BoundsExtractor

Extracts the coordinate values that describe an individual feature’s bounding box (or cube) and stores them as attributes.

2DGridAccumulator

Creates a series of regularly-spaced rectangles that span the extent of all features received (when Type of Grid to Create is Polygons).

2DGridCreator

Creates a series of regularly-spaced rectangles of a specific size and position (when Type of Grid to Create is Polygons).

Tiler and RasterTiler

Do not create actual rectangles, but chop features into a series of rectangular tiles, specified in a similar fashion to the 2DGridAccumulator.

Configuration

Input Ports

Features with geometry to be tiled. Point, curve, area, raster, and point cloud geometries are supported.

Output Ports

Features tiled as specified in parameters.

Any geometries that were unused during tiling.

Features without valid geometry are output via this port, as are features that are invalid in a way that prevents tiling - a geometry that extends to infinity, for example.

The Invalid Parts Handling parameter determines what is output through the port.

If Reject Parts Only is selected then only the parts that caused the feature to be invalid will be output through the <Rejected> port.

If Reject Whole Feature is selected the entire feature will be output through the <Rejected>port.

Rejected features will have an fme_rejection_code attribute with one of the following values:

INVALID_PARAMETER_TILE_WIDTH
INVALID_PARAMETER_TILE_HEIGHT
INVALID_PARAMETER_SEED_COORDINATE_X
INVALID_PARAMETER_SEED_COORDINATE_Y
INVALID_PARAMETER_NUMBER_OF_HORIZONTAL_TILES
INVALID_PARAMETER_NUMBER_OF_VERTICAL_TILES
INVALID_GEOMETRY_NON_SPATIAL
INVALID_GEOMETRY_NOT_FINITE
INVALID_GEOMETRY_TYPE

Rejected Feature Handling: can be set to either terminate the translation or continue running when it encounters a rejected feature. This setting is available both as a default FME option and as a workspace parameter.

Parameters

Group By

The input features may be partitioned into groups based on attribute values.

One tiling operation is performed for each group.

If Group By is not specified, all input features will be processed together.

Complete Groups

Select the point in processing at which groups are processed:

When All Features Received

This is the default behavior. Processing will only occur in this transformer once all input is present.

When Group Changes (Advanced)

This transformer will process input groups in order. Changes of the value of the Group By parameter on the input stream will trigger processing on the currently accumulating group. This may improve overall speed (particularly with multiple, equally-sized groups), but could cause undesired behavior if input groups are not truly ordered.

There are two typical reasons for using When Group Changes (Advanced) . The first is incoming data that is intended to be processed in groups (and is already so ordered). In this case, the structure dictates Group By usage - not performance considerations.

The second possible reason is potential performance gains.

Performance gains are most likely when the data is already sorted (or read using a SQL ORDER BY statement) since less work is required of FME. If the data needs ordering, it can be sorted in the workspace (though the added processing overhead may negate any gains).

Sorting becomes more difficult according to the number of data streams. Multiple streams of data could be almost impossible to sort into the correct order, since all features matching a Group By value need to arrive before any features (of any feature type or dataset) belonging to the next group. In this case, using Group By with When All Features Received may be the equivalent and simpler approach.

Note  Multiple feature types and features from multiple datasets will not generally naturally occur in the correct order.

As with many scenarios, testing different approaches in your workspace with your data is the only definitive way to identify performance gains.

Define Tiles By

Select a tile sizing method:

Dimensions in Ground Units

Specify an exact tile size in ground units.

Number of Tiles

Divide the features’ extents into a specified number of equal tiles.

Starting Corner

Select the corner for the origin of the tiling. Column and row numbering starts at 0,0.

When Define Tiles By is Dimensions in Ground Units, the last column and/or row may extend beyond the bounding box of the input features. The last column/row is opposite the selected Starting Corner.

Dimensions in Ground Units

When Define Tiles By is Dimensions in Ground Units:

Width(X)

Specify the tile width along the x axis, in the ground units of the feature’s coordinate system.

Height(Y)

Specify the tile height along the y axis, in the ground units of the feature’s coordinate system.

Seed Coordinate X

(Optional) Seed coordinates define a point from which the tiles are offset.

They may lie inside or outside the extents of features being tiled.

Seed coordinates can be used in conjunction with Width(X) and Height(Y) to align the tiles with grids or other features, or ensure that cell boundaries fall on particular types of numbers (multiples of 1, 100, or 1000, for example).

Either X, Y, or both coordinates may be seeded.

If neither is specified then the seed point is the Starting Corner.

Seed Coordinate Y

(Optional) See Seed Coordinate X.

If any of these values are supplied via an attribute or expression, the values used are taken from the first encountered feature of the group. Values from subsequent features are ignored

When tiling rasters without coordinate systems or georeferencing, ground units are one (1) per cell and the origin is 0,0.

Number of Tiles

When Define Tiles By is Number of Tiles:

Columns

Specify the number of tiles desired along the x axis.

Rows

Specify the number of tiles desired along the y axis.

If any of these values are supplied via an attribute or expression, the values used are taken from the first encountered feature of the group. Values from subsequent features are ignored

Tolerance

Specify the minimum distance between geometries in 2D before they are considered equal, in ground units:

  • Automatic (default): Tolerance is automatically computed based on the location of the input geometries.

  • Custom Value: Specify an explicit tolerance value.

Duplicate Elements on Tile Borders

Features on the border between tiles may be duplicated so that they appear in both tiles:

  • Yes: Duplicate.

  • No (default): Do not duplicate.

Missing Z Values

Select a method for interpolating z values required after tiling:

  • Planar Interpolation defines a plane based on the input area. Missing values are filled in by mapping the coordinate onto the plane.

  • Linear Interpolation considers values on either side of the missing value and interpolates.

  • None (Drop Values) removes all z values from the features and outputs it in 2D.

  • Custom Value assigns a specified value.

Missing Measure Values

Select a method for handling features that have some measures, but are missing at least one value after tiling:

  • Linear Interpolation considers values on either side of the missing value and interpolates.

  • Nearest Vertex will take the value of the measure from the nearest vertex.

  • None (Drop Values) will cause the incomplete measure values to be removed.

If no value is given for a measure, the measure will be removed.

Invalid Parts Handling

If a feature has geometry with an invalid part:

  • Reject Parts Only: Only the parts that caused the feature to be invalid will be output through the <Rejected> port.

  • Reject Whole Feature: The entire feature will be output through the <Rejected> port.

Preserve Feature Order

This parameter controls the order in which features exit a transformer.

When a transformer has more than one output port, features usually exit one port at a time. At times, it may be useful to keep the order that features arrived in, switching from port to port as necessary. This allows feature order to be preserved, though at a potential cost in processing efficiency.

Select a method for feature ordering.

Per Output Port (Default)

Only preserve the input order of features as they occur within the group of features exiting a given output port.

All features exiting an output port retain their ordering relative to each other (within the group), but not relative to features exiting other output ports.

This option is generally the most efficient, where large chunks of features will exit an output port together (taking advantage of bulk mode).

As features exiting different output ports may not be strictly output in the order they arrived, output ordering may be unpredictable.

Across Output Ports

Strictly preserve the input order of features, regardless of which output port they exit. Features will be output singly in the same order they arrived, switching from port to port as necessary. This option is generally less efficient as the processing gains of bulk mode are less likely to apply - however, feature order is predictable.

Column

Name the attribute to contain column numbers, relative to the Starting Corner. Numbering starts with 0.

Row

Name the attribute to contain row numbers, relative to the Starting Corner. Numbering starts with 0.

Editing Transformer Parameters

Using a set of menu options, transformer parameters can be assigned by referencing other elements in the workspace. More advanced functions, such as an advanced editor and an arithmetic editor, are also available in some transformers. To access a menu of these options, click beside the applicable parameter. For more information, see Transformer Parameter Menu Options.

Defining Values

There are several ways to define a value for use in a Transformer. The simplest is to simply type in a value or string, which can include functions of various types such as attribute references, math and string functions, and workspace parameters. There are a number of tools and shortcuts that can assist in constructing values, generally available from the drop-down context menu adjacent to the value field.

Using the Text Editor

The Text Editor provides a convenient way to construct text strings (including regular expressions) from various data sources, such as attributes, parameters, and constants, where the result is used directly inside a parameter.

Text Editor

Using the Arithmetic Editor

The Arithmetic Editor provides a convenient way to construct math expressions from various data sources, such as attributes, parameters, and feature functions, where the result is used directly inside a parameter.

Arithmetic Editor

Conditional Values

Set values depending on one or more test conditions that either pass or fail.

Parameter Condition Definition Dialog

Content

Expressions and strings can include a number of functions, characters, parameters, and more.

When setting values - whether entered directly in a parameter or constructed using one of the editors - strings and expressions containing String, Math, Date/Time or FME Feature Functions will have those functions evaluated. Therefore, the names of these functions (in the form @<function_name>) should not be used as literal string values.

String Functions

These functions manipulate and format strings.

Special Characters

 A set of control characters is available in the Text Editor.

Math Functions

Math functions are available in both editors.
Date/Time Functions Date and time functions are available in the Text Editor.

Math Operators

These operators are available in the Arithmetic Editor.

FME Feature Functions

These return primarily feature-specific values.

FME Parameters

FME and workspace-specific parameters may be used.
Creating and Modifying User Parameters Create your own editable parameters.

Dialog Options - Tables

Transformers with table-style parameters have additional tools for populating and manipulating values.

Row Reordering

Enabled once you have clicked on a row item. Choices include:

  • Add a row
  • Remove a row
  • Move current row up one
  • Move current row down one
  • Move current row to top
  • Move current row to bottom

Cut, Copy, and Paste

Enabled once you have clicked on a row item. Choices include:

  • Cut a row - delete and copy to clipboard
  • Copy a row to the clipboard
  • Paste a row from the clipboard

Cut, copy, and paste may be used within a transformer, or between transformers.

Filter

Start typing a string, and the matrix will only display rows matching those characters. Searches all columns. This only affects the display of attributes within the transformer - it does not alter which attributes are output.

Import

Import populates the table with a set of new attributes read from a dataset. Specific application varies between transformers.

Reset/Refresh

Generally resets the table to its initial state, and may provide additional options to remove invalid entries. Behavior varies between transformers.

Note: Not all tools are available in all transformers.

Reference

Processing Behavior

Group-Based

Feature Holding

Yes
Dependencies None
Aliases  
History  

FME Community

The FME Community is the place for demos, how-tos, articles, FAQs, and more. Get answers to your questions, learn from other users, and suggest, vote, and comment on new features.

Search for all results about the Tiler on the FME Community.

 

Examples may contain information licensed under the Open Government Licence – Vancouver and/or the Open Government Licence – Canada.

Keywords: raster grid clip subset tile extent bound limit Tessellate Tessellation pointcloud