Licensing options for this format begin with FME Professional Edition.
|
This format refers to the ArcSDE component of an Enterprise Geodatabase. It does not contain Geodatabase application logic, and therefore lacks many features available to a Geodatabase. Use the Esri Geodatabase Reader/Writer (ArcSDE Geodb) format to access a richer set of features available to an Enterprise Geodatabase. See the FME Knowledge Center for a more detailed comparison of Geodatabase and ArcSDE readers and writers. |
Version and Format Overview
This chapter describes FME's support for:
| ArcGIS 10.x and higher |
Other formats included in this chapter:
| SDE30 | Reader and Writer |
| SDERASTER | Reader |
| SDERASTERMAP | Writer |
| SDERASTERCATALOG | Writer |
Esri Spatial Database Engine (SDE) technology is a core component of ArcGIS products. It manages spatial data in a relational database management system (RDBMS). FME is an SDE client application capable of connecting to the SDE, regardless of the platform on which it is located.
Note: Throughout this chapter, SDE refers to clients using ArcSDE 10.x, unless otherwise stated. The same reader/writer is used to access all of these clients.
SDE enables an RDBMS to store both spatial and non-spatial data by providing a new “Shape” column type to the underlying RDBMS.
Overview
The SDE provides a seamless data model into which geographic data is stored. The SDE provides a relational data model organized around tables. In the FME, an SDE feature type1The terms “feature type” and “table” are used interchangeably throughout this chapter. is equivalent to an RDBMS table. FME can be used to read and write any RDBMS table whether or not it has a layer (vector spatial column) and whether or not it has a raster column. Spatial geometry in a table can be found in either a layer or a raster column.
FME’s SDE reader and writer take advantage of the unique capabilities of the SDE. The reader retrieves features from the SDE by constructing queries consisting of both spatial and/or non-spatial components. Since an SDE database may have a very large number of features, the query building capability is critical to ensure that the FME reader is capable of satisfying highly focused data requests. The SDE reader can also perform multi-table join queries, thereby exploiting the full power of the underlying RDBMS.
The writer takes advantage of the SDE’s transaction model to ease the task of importing data into the SDE. The SDE writer can also operate in Update, Delete, or Insert modes, enabling FME to be used as a key component in an SDE-based solution.
Note: Version support, spatial constraints, and multi-table joins are not currently supported for raster data.
Layer (Vector Spatial Column) Properties
A layer (vector spatial column) has the following properties:
-
Each layer has a spatial index that can be tuned specifically for it. The spatial index consists of between one and three two-dimensional (2D) grids. The sizes of the grid elements are ordered such that:
grid1 size < 4 X grid2 size (except if grid2 is set to zero)
grid2 size < 4 X grid3 size (except if grid3 is set to zero)
Tip: Since the SDE stores all coordinates as 64-bit integer coordinates with an implied decimal position, it is possible for precision to be lost or for overflow to occur when features are stored in the SDE. Care must be taken to ensure that the SDE dataset system units preserve the data precision and the range.
- A single relational table can only have 1 layer.
- All features in a layer must be either two- or three-dimensional (2D or 3D). Mixed dimensionality is not allowed in a layer
- Each layer has its own coordinate system, false origin, and scaling factor.
- The layer in a raster catalog is referred to as the ‘footprint’ column, and stores the bounding box of each raster in the catalog.
Raster Column Properties
A raster column has the following properties:
- A single relational table can only have 1 raster column.
- Each raster column has its own coordinate system. If the coordinate system is not specified, it will be stored as
UNKNOWN. - A raster column can either be a raster map storing all raster data in the table as a single raster in a single row, or as a raster catalog storing multiple rasters in multiple rows in the table.