Spatial Data Sources > Raster Data Sources

This type of spatial data source can read georeferenced TIFF image files. JMap supports two types of georeferenced tiff images: tiff files with tfw files (the tfw files contain georeferenced data) or geotiff files (georeferenced data inside image file).

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, lower resolution images are created by JMap Server and stored in the image cache (pyramid of images). The image cache is then used to produce images on the fly at specific resolutions with optimal performance. Depending on the initial image sizes and parameters, the image cache can become voluminous. Typically, the space used by the cache is the same size as the original images. Available disk space must be sufficient before updating this data source.

Note: This type of data can also be read by the GDAL data source with the same performance. This data source is kept for compatibility with existing configurations.

Parameters
Selected files	Select one or more image files to read. If several files are selected, they will be considered as a mosaic. The files must be georeferenced.

The other parameters don't need to be modified most of the time.

Reader options
Cache path	The directory where JMap Server will store generated image files for the various resolutions. Default is JMAP_HOME/cache/raster.
Interpolation type	Method for producing images with reduced resolutions from images with higher resolutions. Default is bicubic and usually gives the best results.
Compression type	Type of compression of the lower resolution images in cache. Default is none and offers the best performances but uses more disk space.

Resolutions
Resolutions	Number of lower resolution images to prepare and resolution ratio in relation to the higher resolution images. Default is 8 with each image resolution divided by 2. All these resolutions form the pyramid of images.