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

• ImageMosaicFormat (javadoc)
• ImageMosaicJDBCReader (javadoc)
• Image Pyramid Plugin
• Using the ImageMoasic plugin

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 CoordianteReferenceSystem.

• 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