BIL, Band Interleaved by Line, is an ESRI format used for raster data. When exporting to BIL, .prj and .mapmeta files are written. See the Exporting topic.
To import from BIL format:
Choose File-Import from the main menu.
In the Import dialog browse to the location of the files and double-click on the .bil file.
A table and one or more images will be created.
Use Style to style an image if it shows terrain elevation or other non-photographic raster information.
BIL files may be accompanied by a prj file that gives projection information, in which case the system will automatically assign the correct initial projection. If no projection information accompanies the file or if the projection information is wrongly specified, we must launch Assign Initial Coordinate System in the Component pane to specify the correct initial projection for the imported component.
In the dialog seen above we can see that the BIL file we are using is accompanied by a prj file, so there is a good chance that the projection information will be correct upon import.
The particular BIL file imported contains a raster data set that codes vegetation types as one of 22 different pixel values. Using Style to color it with a palette we can create the above display, shown as a layer in a map together with a Bing streets image server data source background layer to provide context. We can see that the projection information provided by the .prj was correct, so the image created can be correctly overlaid in a geographic context.
Zooming in we see how the different pixel regions code for different types of vegetation.
The above BIL is relatively simple in that it provides a single band of data which is easy to color using Style to provide an understandable display. BIL files will often contain multiple data bands that use a very wide variety of values and which can sometimes require considerable tinkering to create an understandable display.
For an example, see the Example: Import BIL and Combine 3 Bands topic.
Projections - Take care to find any available commentaries or metadata information that may accompany the BIL files in use. BIL files, especially older ones, may use idiosyncratic ways of specifying projections that are different from modern practise and which will result in imports that do not correctly specify projection information. In that case, we will have to use whatever documentation we can find on the data set to learn what the correct projection should be so we can specify it using Assign Initial Coordinate System.
Z exports - Exporting will apply Z offset / scale values to pixels.
Assign Initial Coordinate System
Example: Import an ESRI ADF File and Apply Style and Hillshading
Example: Import BIL and Combine 3 Bands