Esri Geodatabase (File Geodb Raster Catalog) Reader Parameters

After specifying the database connection, click the Browse button (...) to select tables for import. A connection window appears while the system retrieves the tables from the database.

Once the Select Tables dialog appears, you can select one or more tables. Click OK to dismiss the window and add the selected table name(s) to the Tables parameter.

This parameter is used to constrain the row selection in tables chosen in the Tables parameter.

The easiest method to construct a WHERE clause is by using the editor. Click the browse button (...) to open the editor, and use the SQL functions to construct the clause. You can also type a WHERE clause directly in the parameter field:

Examples
When querying integer and number data types: NUMLANES = 2 LENGTH > 2000

If the WHERE clause SQL is invalid, the translation will fail.

Use this parameter to expose Format Attributes in FME Workbench when you create a workspace:

• In a dynamic scenario, it means these attributes can be passed to the output dataset at runtime.
• In a non-dynamic scenario, this parameter allows you to expose additional attributes on multiple feature types. Click the browse button to view the available format attributes (which are different for each format) for the reader.

This parameter controls how Geodatabase aliases are used.

• None – Aliases are ignored.
• Replace Attribute Names with Aliases – (only applicable when adding a Reader) Attributes on feature types will be named for their aliases rather than their official names. A geodb_feature_class_alias attribute will be included on each feature. Use this mode when the target format should create feature types using the aliases as attribute names.
• Expose Aliases as Metadata Attributes – For each attribute read, a second <name>_alias attribute will be added that stores the alias for the attribute in question. A geodb_feature_class_alias attribute will also be included on each feature. Use this mode when the target format is Geodatabase and the aliases should be preserved during feature class and table creation.

A search envelope (also known as a bounding box) is a rectangular area that defines a geographic area. In FME, the easiest way to define a search envelope is to use search envelope parameters.

Defining a search envelope is the most efficient method of selecting an area of interest because FME will read only the data that is necessary – it does not have to read an entire dataset. Search Envelope parameters apply to both vector and raster datasets and can be particularly efficient if the source format has a spatial index.

Most FME readers have parameters to define the search envelope of data that is being read:

The parameters include the x and y coordinates of the bounding box as well as a parameter that defines the coordinate system.

How to Define the Bounding Box

Using the minimum and maximum x and y parameters, define a bounding box that will be used to filter the input features. Only features that intersect with the bounding box are returned. Note that the bounding box intersection is not a full geometry intersection (based on spatial relationships) that would be returned by a transformer like the SpatialFilter.

Note: If all four coordinates of the search envelope are left at 0, the search envelope will be disabled even if this option is checked.

Search Envelope Coordinate System

Specifies the coordinate system of the search envelope if it is different than the coordinate system of the data. The coordinate system associated with the data to be read must always be set if this parameter is set.

If this parameter is set, the minimum and maximum points of the search envelope are reprojected from the Search Envelope Coordinate System to the reader’s coordinate system prior to applying the envelope.

The underlying function for Use Search Envelope is an intersection; however, when Clip to Search Envelope is checked, a clipping operation is also performed.

• When checked (set to Yes), this option instructs FME to clip features to the exact envelope boundary. FME removes any portions of imported features being read that are outside the search envelope.
• When left unchecked (set to No), features that overlap the boundary will be included in their full (unclipped) form.

Clip to Search Envelope: No	Clip to Search Envelope: Yes
Any features that cross the search envelope boundary will be read, including the portion that lies outside of the boundary.	Any features that cross the search envelope boundary will be clipped at the boundary, and only the portion that lies inside the boundary will be read.
The search envelope includes the bounding box and the extent of the raster.	The search envelope includes only the area within the bounding box. The raster size will still match the bounding box, but the area without data will be filled with Nodata values to represent the absence of data, if the source raster has them. Raster Nodata may be a single value across all bands, a single value per band, or a separate alpha or transparency band that indicates the lack of data values (this is more common in images than other types of rasters).

Managed rasters, rasters stored within the Geodatabase, represent Nodata as a bit mask on each band. This parameter specifies how to handle these Nodata bit masks.

• None – Nodata bit masks will be ignored
• Single Alpha Band (default) – Nodata bit masks for each band are merged into a single additional alpha band named geodb_nodata.

If merged into a single alpha band, then the alpha band will contain a value of 0 (Nodata) at a given cell if and only if the corresponding cell of all the other bands is Nodata.

This parameter only affects managed rasters. Unmanaged rasters, rasters stored in files outside the Geodatabase, have Nodata represented as a Nodata value per band and do not have Nodata bitmasks.