BMGReprojector
Reprojects feature coordinates from one coordinate system to another using the Blue Marble Geographic Calculator library.
Parameters
This transformer allows you to specify the coordinate transform through a parameter settings dialog containing controls similar to those found in the Blue Marble Desktop. The controls use the coordinate system definitions (data source), shift data files and workspace settings from a required local installation of the Desktop.
Click the browse buttons next to the text fields to select a source coordinate system, and optionally the source coordinate units of measure, vertical reference and vertical coordinates units of measure. Whenever the user changes the coordinate system, the units of measure is set to the new system's specified units and any vertical reference is cleared. Right-click on the text fields to view the selected object's definition in the Blue Marble data source.
Click the browse buttons next to the text fields to select a destination coordinate system, and optionally the destination coordinate units of measure, vertical reference and vertical coordinates units of measure. Whenever the user changes the coordinate system, the units of measure is set to the new system's specified units and any vertical reference is cleared. Right-click on the text fields to view the selected object's definition in the Blue Marble data source.
Click the browse button next to the text field to select a datum shift between the currently-specified coordinate systems. Selecting a datum shift is necessary when the two coordinate systems have different horizontal datums.
Note: Whenever you change one of the coordinate systems, the datum shift is cleared; you should re-select it before closing the dialog.
Right-click on the text field to view the datum shift's definition in the Blue Marble data source.
The Interpolation Type affects only raster data. Cell values are interpolated in order to change the raster to the specified size.
Nearest Neighbor is the fastest but produces the poorest image quality.
Bilinear provides a reasonable balance of speed and quality.
Bicubic is the slowest but produces the best image quality.
Average 4 and Average 16 have a performance similar to Bilinear and are useful for numeric rasters such as DEMs.
The Cell Size applies only to raster features.
Square Cells: The number of rows and columns as well as the spacing will be changed to maintain approximately the same cell ground area and form square cells where the horizontal and vertical cell sizes are equal.
Like the Square Cells option, Preserve Cells will change both the number of rows and columns and the spacing to maintain cell ground area, but will also try to preserve the original cell aspect ratio, taking into account any warping caused by the reprojection.
Stretch Cells: The cell size of the raster will be adjusted to maintain the same number of rows and columns in the reprojected raster as there were in the input raster.
Usage Notes
The BMGReprojector is supported on the 32-bit Windows edition of FME only.
Any coordinate system set on the input features is ignored. A user-specified source coordinate system is required.
Vertical transformations may require specific grid shift files that are available at www.bluemarblegeo.com.
This transformer works with both raster and vector data, and is not affected by raster band and palette selection.
Licensing
This transformer requires the following licenses from Blue Marble Geographics to be installed:
- Blue Marble Geographic Calculator. For more information, see http://www.bluemarblegeo.com/products/geographic-calculator.php.
- Blue Marble FME Reprojector. This plugin is installed with FME Desktop, but requires a special license to use. For more information, contact info@bluemarblegeo.com.
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.
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.
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.
These functions manipulate and format strings. | |
Special Characters |
A set of control characters is available in the Text Editor. |
Math functions are available in both editors. | |
Date/Time Functions | Date and time functions are available in the Text Editor. |
These operators are available in the Arithmetic Editor. | |
These return primarily feature-specific values. | |
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
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Enabled once you have clicked on a row item. Choices include:
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Cut, Copy, and Paste
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Enabled once you have clicked on a row item. Choices include:
Cut, copy, and paste may be used within a transformer, or between transformers. |
Filter
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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
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Import populates the table with a set of new attributes read from a dataset. Specific application varies between transformers. |
Reset/Refresh
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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.
FME Community
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