Page History

...

The file format was documented by ESRI online. (PDF version) and supports integer (1- to 32- bit) pixel values in signed or unsigned format, in either little- or big endian storage order. The 1- and 4- bit integer pixel formats have not been implemented (yet) as they seem less useful for FEWS, but the rest of the documentation is fully implemented.

Note: It is assumed that your data is using unsigned integers, unless the keyword "pixeltype" is used and its value is"signedint".

BIL files in FEWS

In the Public Interface (PI interface) of FEWS, an implementation of the BIL format is also provided, as documented here.

...

This new implementation is fully compliant with the ESRI technical specifications and can be configured with the new "BILBIPBSQ" identifier, whereas the existing PI implementation of FEWS BIL files uses the identifier "BIL".

Using NoData for missing values

In the header files (*.HDR) which normally come with a BIL / BIP / BSQ file, a NoData field can be used to define the numerical value which has been assigned to pixels for which there is no valid data.  This field is not mentioned in the ESRI documentation but it's usage is very common, as follows:

	NODATA -999

The result if this example is identical to defining <missingValue>-999</missingValue> in the import configuration.

Using NBLOCKS for time series

...

	copy /b step1.bil+step2.bil+step2step3.bil+step4.bil 4steps.bil

...