Spatial Data Sources > Raster Data Sources > GDAL (Geospatial Data Abstraction Library)

This type of spatial data source allows you to read a wide variety of raster data formats. GDAL (Geospatial Data Abstraction Library) is an open source library specializing in raster data conversion and processing.

There can be one or more source image files (mosaic of images). The images of the mosaic can overlap and there can be holes in the mosaic.

When the data source is updated, if the option is activated, a pyramid of lower resolution images is created by JMap Server and stored in the image cache. The image cache is then used for high performance production of images on the fly at specific resolutions. Depending on the initial image sizes and parameters, the image cache size can become voluminous. Typically, the total image cache is about the same size as the original images. Available disk space must be sufficient before updating this data source. It is possible that the data format selected will not require the creation of a pyramid. In this case, the parameter will be ignored.

Parameters
Selected files	Select one or more image files to read. If many files are selected, they will be considered as a mosaic. The files must be georeferenced.
Cache path	The directory where JMap Server will store generated image files for the various resolutions. Default is JMAP_HOME/cache/raster.
Image interpolation	Method for producing images with reduced resolutions from images with higher resolutions. Default is "Cubic" and this method usually produces the best results.
Compute statistics (may take some time)	Statistics on image pixels simplify the analysis of these images. JMap extensions such as Imagery use these statistics to work. Calculating statistics can take several minutes and this option should only be activated when necessary. If you do not need statistics, do not enable this option.
Create a pyramid	Activates the creation of an image pyramid with several resolutions. This greatly improves performance for producing images on the fly.
Pyramid image interpolation	Method used to produce pyramid images. The default value is "Cubic" and this method usually produces the best results.