Despite the very widespread false idea according to which the geodatabases file ( .gdb ) cannot be read and modified using tools within the Esri ArcGIS platform, recent versions of GDAL (and therefore using applications such GDAL- queQGIS ) are capable of, effectively, read and extract information from the geodatabases file . The geodatabase file format has become a very common format for storing and exchanging data space , in particular since it allows the storage of multiple data layers and that allows the storage of data layers exceeding the limits of others specifications . ArcGIS users, regularly, use geodatabases file when the attribute tables exceed the storage capacity of a shapefile attribute table ( a DBF file is limited to ~ 2 GB in size ).
The GDAL users who work with geodatabases file should know that GDAL includes henceforward a very robust open source, read- only driver for the geodatabase format file : OpenFileGDB . The specifications indicate that this driver is able to, efficiently, read the contents of databases with a large number of fields, without any dependent proprietary software.
An additional option allowing to interact with geodatabases file using GDAL is the FileGDB.FileGDB driver dependant on Esri’s File Geodatabase SDK , but it provides reading and writing access to geodatabases file. However, internal tests at geospatial @ UCLA said that for read-only geodatabase file operations, FileGDB driver can be many orders of magnitude slower than the OpenFileGDB driver .
Therefore those users who have to edit, regularly, geodatabases file should install and use the FileGDB driver, while users who need only to convert the contents of the geodatabase file to other formats should use the OpenFileGDB driver.
The QGIS users can read geodatabases file by draging geodatabases, ending with extension.gdb directly in the layers window. The geodatabase can appear as a folder and cannot be selected using the Add vector layers tool in QGIS. The contents of the geodatabase file appear in the layers window , and each layer can be exported to another format with the writing support in GDAL, including the shapefile format.
For large geodatabases whose content exceeds the limits of the shapefile specification we recommend using GDAL ogr2ogr command line interface to copy the content of a geodatabase file directly to a PostGIS database. Use the following command, by replacing the bracketed text with appropriate values for your configuration (the brackets should not be included in your order ):
ogr2ogr-progress – overwrite – skipfailures -f “PostgreSQL” PG: ” host = localhost user = dbname [ postgres ] = [ dbname ] password = [password]” “[ pathtofilegdb ]. gdb ” “[ tablename ]”
