Mosaic Plugin

This format make use of a shapefile to act as a kind of index, the features in this shapefile list the filename of the “images” to display and the location in which they should be displayed.

Reference

Maven:

<dependency>
  <groupId>org.geotools</groupId>
  <artifactId>gt-imagemosaic</artifactId>
  <version>${geotools.version}</version>
</dependency>

Example

An example data set looks something like:

bluemarble.shp
bluemarble.prj
bluemarble.properties
... a bunch of raster files ...

  • Shapefile file

    The schema of your shapefile is important:

    You MUST have a attribute called “location”, this will be used to look up the raster files

  • PRJ file

    The usual projection file associated with a shapefile, using the WKT format for a CoordinateReferenceSystem.

  • Properties File

    The property file is REQUIRED and use to provide a bunch of settings:

    Example bluemarble.properties:

    #
#Thu Jan 11 14:53:30 CET 2007
Name=modis
ExpandToRGB=true
Levels=10000.0,10000.0
LevelsNum=1
Envelope2D=-3637013.0,-1158091.0 1019969.0,4092819.0
NumFiles=3

    Where the following are required:

    • Name

    • ExpandToRGB: true if we need to expand the color model from indexed to rgba

      • If all your images use the same indexed palette you can set this to false and get a large performance gain

    • Levels: list of resolutions

      • Format: level_0_x_resolution, level_0_y_resolution, level_1_x_resolution, level_1_y_resolution

      • This measure of resolution describes how big each pixel is in real world units

      • Sample calculation: envelope.getLength(0) / image.getWidth()

      • You can define several levels in order to capture overview files if you have them

    • LevelsNum: the number of levels mentioned above

    • Envelope2D: bounds in the CRS specified in the .prj file

    • Format: minX,minY maxX,maxY

    • NumFiles: should be the same as the number of features in your shapefile