Import multiple WorldImages in a single GeoServer store

Question

I downloaded tiles from Copernicus EU DEM. Each tile is made of four files :

$ ls *E30N30*
eu_dem_v11_E30N30.TFw
eu_dem_v11_E30N30.TIF.aux.xml
eu_dem_v11_E30N30.TIF
eu_dem_v11_E30N30.TIF.ovr

I guess these are WorldImage files ? Now I am trying to create a store from them in GeoServer. However the WorldImage store type only seems to accept single WorldImages, and the ImageMosaic store type fails to load data with

Could not list layers for this store, an error occurred retrieving them:
Failed to create reader from file:///data/source/Copernicus_EU_DEM_v1.1 and hints
Hints: REPOSITORY = org.geoserver.catalog.CatalogRepository@433abb55
_EXECUTOR_SERVICE = java.util.concurrent.ThreadPoolExecutor@13eb5bc5[Running, pool size = 0, active threads = 0, queued tasks = 0, completed tasks = 0]
System defaults:
FILTER_FACTORY = FilterFactoryImpl
FEATURE_FACTORY = org.geotools.feature.LenientFeatureFactoryImpl@2081b1a2
LENIENT_DATUM_SHIFT = true
FORCE_AXIS_ORDER_HONORING = http
COMPARISON_TOLERANCE = 1.0E-8
GRID_COVERAGE_FACTORY = GridCoverageFactory
TILE_ENCODING = null
STYLE_FACTORY = StyleFactoryImpl
FORCE_LONGITUDE_FIRST_AXIS_ORDER = true

(I had a similar issue with another dataset earlier because the dataset directory was missing write access for tomcat user. This is not the same case here, the permissions are right.)

How am I supposed to load these tiles ?

Answer 1

The problem is most likely that GeoServer can't work out the projection of the world image files. If you import them individually it will ask you for the projection before displaying them. In the case of an image mosaic there is no provision for asking you for the projection of each tile (it would take too long).

So you have a variety of possible solutions:

1. Add a .prj file to each of the tifs to tell GeoServer what the projection is - I wrote a blog post about a small tool I wrote to do this.

2. Use GDAL tools to convert the files to a "real" GeoTiff with the projection correctly set. Something like:

   gdal_translate -a_srs epsg:xxxx in_file.tif out_file.tif 
   

3. Stuff all the tifs into a VRT (setting the projection with -a_srs), convert that to an image mossaic (or pyramid) using gdal_retile.