GDAL – Accessing File Geodatabase (.gdb) Rasters via GDAL in Python

file-geodatabasegdalpython

I'm working on a tool that converts raster layers to arrays for processing with NumPy, and ideally I would like to be able to work with rasters that come packaged in a .gdb without exporting them all (especially if this requires engaging ArcGIS or ArcPy).

Is this possible with the OpenFileGDB driver?

From what I can tell this driver seems to treat raster layers the same as vector layers, which gives you access to some data about the layer but doesn't give you the ReadAsArray functionality.

Best Answer

Reading and writing file geodatabase rasters is not supported by the File Geodatabase API as of July 2015. According to this 2010 Esri blog File Geodatabase API details:

Rasters (Raster Dataset, Raster Catalog, Mosaic Datasets and Raster Attributes) are not supported with the initial release of the File Geodatabase API.

Additionally, according to an Esri Staff member on a Geonet discussion (June 2015):

Currently we do not have any plans on supported access to raster data via the File Geodatabase API. If you feel this is needed, please add it to the Esri Ideas site and it will be considered for a…

Related Solutions

Python GDAL – Access Feature Classes in File Geodatabases

You're almost there. This is on Windows 7, Python 2.6.5 32bit, and GDAL 1.9.0:

>>> from osgeo import ogr
>>> driver = ogr.GetDriverByName("FileGDB")
>>> ds = driver.Open(r"C:\temp\buildings.gdb", 0)
>>> ds
<osgeo.ogr.DataSource; proxy of <Swig Object of type 'OGRDataSourceShadow *' at 0x02BB7038> >
>>> ds.GetLayer("buildings")
<osgeo.ogr.Layer; proxy of <Swig Object of type 'OGRLayerShadow *' at 0x02BB7050> >
>>> b = ds.GetLayer("buildings")
>>> sr = b.GetSpatialRef()
>>> sr
<osgeo.osr.SpatialReference; proxy of <Swig Object of type 'OSRSpatialReferenceShadow *' at 0x02BB7080> >
>>> sr.ExportToProj4()
'+proj=utm +zone=15 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs '
>>>

Once you open the FGDB, then use GetLayer to get at your featureclass.

[GIS] Reading data from raster band with Java and GDAL

There are a few ways to read the data. Forgive me, but I am not familiar with the java bindings and syntax. One method is to use GDALRasterBand->ReadBlock():

http://gdal.org/classGDALRasterBand.html#a09e1d83971ddff0b43deffd54ef25eef

That reads in the internal block defined by the driver, which is one scanline for the aaigrid driver. See the example in the documentation. To do this manually, similar to your example, use GDALRasterBand->RasterIO(), which appears to be wrapped in java with ReadRaster(). Loop over the raster GDALDataset->GetRasterYSize() times and read in one line:

double[]data = new double[nXSize];
for(int i = 0; i < nYSize; i++)
{
    band.ReadRaster(0, i, nXsize, 1, data);
    //do something with your data
}

You can change the size of your input window for whatever you would like to get from your data. For example, as above, use a 3x3 window on the ReadRaster() call to calculate slope and aspect. I just found a link to the javadoc here:

http://gdal.org/java/

Best Answer

Related Solutions

Python GDAL – Access Feature Classes in File Geodatabases

[GIS] Reading data from raster band with Java and GDAL

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