Tiler

If Group By attributes are selected, features with the same values in the Group By attributes are placed into the same set, and clipping occurs in each set independent of other sets.

Process At End (Blocking): This is the default behavior. Processing will only occur in this transformer once all input is present.

Process 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.

Considerations for Using Group By

There are two typical reasons for using Process 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 Process At End (Blocking) 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.

Tile Size: This option enables the Tile Width and Height parameters, which allow you to specify the width and height of each tile in ground units.

Number of Tiles: This option enables the Number of Horizontal and Vertical Tiles parameters, which allow you to specify the number of tiles that will be produced.

These parameters are required when the Tiling Type is Tile Size, and allow you to specify the size of each tile in ground units (for example, 100m x 100m).

Note: If the source is a raster, does not have a coordinate system and is not georeferenced, then the raster extents and spacing are adjusted to default values. The horizontal and vertical spacing are set to one column and one row, respectively, and the origin is set to (0,0).

Note: IMPORTANT: If attributes are used for the Tile Width or Tile Height parameters, the value will be taken from the first feature to enter the transformer. An error will occur if this feature does not have these attributes.

These optional parameters specify a "seed point" from which tiles will be generated. Note that it is permissible to specify a value for only one of these parameters—not necessarily both.

These parameters are required when the Tiling Type is Number of Tiles, and allow you to specify how to tile the input data (for example, 5 horizontal tiles and 5 vertical tiles).

The minimum distance between geometries in 2D before they are considered equal, in ground units. If the tolerance is None, the geometries must be exactly identical to be considered equal. If the tolerance is Automatic, a tolerance will be automatically computed based on the location of the input geometries. Additionally, a custom tolerance may be used.

Chooses a starting corner for the purposes of numbering rows and columns. Also, when Tiling Type is Tile Size, the last row and/or the last column may extend beyond the bounds of the input features; here the “last” row or column is the one opposite the Starting Corner.

This parameter allows elements along the border of more than one tile to be duplicated and added to each tile that they touch.

This parameter specifies how to deal with geometries that have a measure, but are missing at least one value, or that have z values, but are missing at least one value. None (Drop Values) will cause the incomplete measure or z values to be removed. Compute will look at the values on either side of the missing value, and then provide an estimate. Additionally, the missing values can be filled in by a custom default value.

In any mode, if no value is given for the z values, the output will be 2D. If no value is given for a measure, the measure will be removed.

When using the Compute mode to compute missing measure values, measures can be considered Continuous, and linearly interpolated from their neighbors, or they can be Discrete, and taken exactly from the nearest neighbor.

If set to Yes, then contiguous lines that constitute the boundary of the output features will be left as separate segments in a path. The default is No, which means that such lines will be joined into longer lines in the output unless they have different properties (for example, traits, measures, and geometry name).

Each feature output from the Tiler will have a row and a column attribute added, specifying the zero-based row and column that the feature fell into.  Row 0, Column 0 corresponds to the tile in the bottom-left corner.