Geodatabase in Field-Map

Field-Map version X6 introduces a new way of handling spatial data.

Since Field-Map version 1, Field-Map references geographic data stored in shapefiles. Shapefiles are kept outside database tables in separate folders within a Field-Map project.

A geodatabase is an alternate way to store geographic information directly in the Field-Map database. It is a less “messy” way of organizing data than having multiple shapefiles in multiple folders. It means physical store of geographic information together with other attributes in datatables of the Field-Map database. This solution is often very advantageous; e.g. in case of using Field-Map Synchronization functionality, storing geographic information in the database smoothes data transfer. On top of this, it enables openning Field-Map projects in any other GIS application that provides data viewing, editing, and analysis.

Field-Map users can switch from shapefiles to geodatabase on the “General“ pane of “Field-Map Settings“.

Picture 1 – Field-Map Settings

Field-Map stores geographic information using well-known binary format (WKB) that is supported by various database engines and GIS programs. WKB is a standardized format for storing spatial objects in relational databases developed by Open Geospatial Consortium and defined in ISO/IEC standard. More information is available at http://www.opengeospatial.org/standards.

Field-Map stores geographic information in attributes named with “FMGIS_“prefix as BLOB (Binary Large Object – a collection of binary data stored as a single entity in a database table).

Picture 2 – Example of Field-Map data table

WKB, the standardized format for storing spatial objects in relational databases, can represent 18 distinct geometric objects starting from the geometry primitives (2D): point, line and polygon.

Field-Map point layers keep the geographic information in attribute called FMGIS_POINT.

Picture 3 – Example of Field-Map data table called "Points"

Field-Map line layers keep the geographic information in attribute called FMGIS_LINE.

Picture 4 – Example of  Field-Map data table called "Lines"

Field-Map polygon layers keep the geographic information in attribute called FMGIS_POLYG.

Picture 5 – Example of Field-Map data table called "Polygons"

Field-Map, as a forestry technology, introduces a tree layer. A single tree consists of a centre point, a circular polygon circumsribing DBH and a polygon circumsribing horizontal crown projection.

That is why a tree table has more FMGIS attributes:  FMGIS_POINT, FMGIS_POLYG and FMGIS_CROWNPROJ_POLYG.

Picture 7 – Example of Field-Map data table called "Trees"

OpenGIS applications that are compliant with the OGC OpenGIS Specifications have unlike Field-Map two significant limitations:

• only one geometry column per table is allowed
• a meta data table called GEOMETRY_COLUMNS with geometry definitions must be created; the GEOMETRY_COLUMNS table consists of three columns :
  • F_TABLE_NAME: name of the feature table containing the geometry column
  • F_GEOMETRY_COLUMN: The name of the geometry column in the feature table
  • GEOMETRY_TYPE: The type of the spatial object

To enable direct displaying FieldMap data in a OpenGIS software, Field-Map automatically creates:

• a set of views (virtual tables) for geographic layers with only one geometry column per view; if a Field-Map data table of a geographic layer contains more than one geometry column (polygon layers, tree layers, deadwood layers), more views are created for such Field-Map data table
• the GEOMETRY_COLUMNS meta data table with geometry definitions that references the views:
  • F_TABLE_NAME: Name of the Field-Map view containing the geometry column
  • F_GEOMETRY_COLUMN: Name of the geometry column in the Field-Map view
  • GEOMETRY_TYPE: The type of the spatial object

For each Field-Map point layer (Field-Map point layers include one geometry column) one view called wPointLayerName_point is created.

For each Field-Map line layer (Field-Map line layers include one geometry column) one view called wLineLayerName_line is created.

For each Field-Map polygon layer (that keep the geographic information in two geometry columns) two views called wPolygonLayerName_point and wPolygonLayerName_polyg are created.

For Field-Map tree layer (that keep the geographic information in three geometry columns) three views called wTreeLayerName_point, wTreeLayerName_BasalArea_polyg and wTreeLayerName_CrownProj_polyg are created.

Example: A Field-Map project consists of one tree layer, one deadwood layer, one point layer, one line layer, one polygon layer and a transect layer.

Picture 8 – Example of Field-Map pfoject structure

Picture 9 – Example of Field-Map project database – Data tables and Views

Picture 10 – Example of a Geometry_columns table