Esri Geodatabase (File Geodb Raster Dataset) Reader Parameters

Geodatabase

Click the browse button to select a File Geodatabase.

Constraints

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.

  • Features – The reader outputs features stored within tables.

  • Metadata – Provides the ability to read table-level metadata. In this mode, the reader outputs one feature per feature type. The geodb_type of the feature is geodb_metadata and the entire XML metadata document belonging to the Geodatabase table is found in the attribute geodb_metadata_string.

Where applicable, the following attributes are also supplied:

Attribute

Description

fme_feature_identifier

The name of the object ID field.

fme_contains_spatial_column

Indicates whether the table has a geometry column (feature class).

fme_geometry{0}

The types of geometry the feature class contains.

fme_dimension

Indicates whether the feature class is 2D or 3D.

If the table is a feature class, the geometry of the metadata feature returned is a polygon, representing the extents of the feature class, and the coordinate system of the feature class is also set on the feature.

When reading metadata, the feature type parameters are used to determine which feature types should have metadata read from them.

Mosaic Parameters

A Mosaic Dataset is a collection of rasters that can be combined to produce a single raster image for viewing or analysis. This parameter provides options to combine the rasters to produce the desired result. They do not apply to raster datasets. The options are based on the mosaic options provided for mosaic datasets in ArcGIS. See Esri documentation for a more detailed explanation.

The following values are supported:

  • None – Rasters will be ordered in the order they appear in the mosaic dataset catalog table.
  • By Attribute – Rasters will be ordered by how close the value of the attribute given by Order Field is to the value supplied in Order Base Value.
  • Closest to Center – Rasters are ordered by how close they are to the center of the combined image.
  • Lock Raster – Only those rasters given in Lock Raster ID will be combined in the order listed
  • North-west (default) – Rasters are ordered by how close they are to the north-west of the combined image.
  • Seamline – Rasters will be combined using the existing seamlines.

When the value of Mosaic Method is set to By Attribute then this parameter specifies which field in the mosaic dataset’s attribute table will be used to compare values.

When the value of Mosaic Method is set to By Attribute then rasters will be ordered by how close the value of the field given by Order Field is to the value given in this parameter.

This parameter lists the ObjectIDs as a comma-separated list that will be used to give the order of the rasters when the value of Mosaic Method is set to Lock Raster.

Gives the option to reverse the order the rasters will be combined.

  • Ascending – Those ordered first will be placed on top.
  • Descending – Those ordered first will be placed on the bottom.

It is possible for more than one raster to overlap in any given area. The mosaic operator specifies how the cells in the overlapping area are combined:

  • First – The cell from the first raster is chosen.
  • Last – The cell from the last raster is chosen.
  • Min – The cell with the smallest value is chosen.
  • Max – The cell with the largest value is chosen.
  • Mean – The average of all the cells is chosen.
  • Blend – Overlapping cells will blended together based on a weight-based algorithm that uses the distance of the cells to the edge within the overlapping area.
  • Sum – The total value of all the pixels added together from overlapping raster datasets.

Schema Attributes

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.

Spatial

Coordinate systems may be extracted from input feature data sources, may come predefined with FME, or may be user-defined. FME allows different output and input coordinate systems, and performs the required coordinate conversions when necessary.

How FME Processes Coordinate Systems in the Workspace

If a coordinate system is specified in both the source format and the workspace, the coordinate system in the workspace is used. The coordinate system specified in the source format is not used, and a warning is logged. If a source coordinate system is not specified in the workspace and the format or system does not store coordinate system information, then the coordinate system is not set for the features that are read.

If a destination coordinate system is set and the feature has been tagged with a coordinate system, then a coordinate system conversion is performed to put the feature into the destination system. This happens right before the feature enters into the writer.

If the destination coordinate system was not set, then the features are written out in their original coordinate system.

If a destination coordinate system is set, but the source coordinate system was not specified in the workspace or stored in the source format, then no conversion is performed. The features are simply tagged with the output system name before being written to the output dataset.

For systems that know their coordinate system, the Coordinate System field will display Read from Source and FME will read the coordinate system from the source dataset. For most other input sources, the field will display Unknown (which simply means that FME will use default values). In most cases, the default value is all you'll need to perform the translation.

You can always choose to override the defaults and choose a new coordinate system. Select More Coordinate Systems from the drop-down menu to open the Coordinate System Gallery.

Changing a Reprojection

To perform a reprojection, FME typically uses the CS-MAP reprojection engine, which includes definitions for thousands of coordinate systems, with a large variety of projections, datums, ellipsoids, and units. However, GIS applications have slightly different algorithms for reprojecting data between different coordinate systems. To ensure that the data FME writes matches exactly to your existing data, you can use the reprojection engine from a different application.

Note  To use this feature, you must have a supported GIS application installed on your system (for example, Esri ArcGIS®).

To change the reprojection engine, Select Workspace Parameters > Spatial > Reprojection Engine. In the example shown, you can select Esri (but the selection here depends on your installed applications):

For more information, see the links below:

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:

Screenshot with blank search envelope min and max x and y parameters

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.

Clip to Search 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 left unchecked (set to No), features that overlap the boundary will be included in their full (unclipped) form.
  • 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.

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).

Advanced

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.