With a simple modification we can pass to 'org.geotools.gce.geotiff.GeoTiffFormat' even URLs as sources. We can change the method 'public GridCoverageReader getReader(Object source)' as follow: ... import java.net.URL; import java.net.URLDecoder; ... public GridCoverageReader getReader(Object source) { if (source instanceof CatalogEntry) { source = ((CatalogEntry) source).resource(); } GridCoverageReader reader = null; if (accepts(source)) { if (source instanceof URL) { URL url = (URL) source; try { final String pathname = URLDecoder.decode(url.getFile(),"UTF-8"); reader = new GeoTiffReader(this, new File(pathname), null); } catch (Exception e) { reader = null; } } else { reader = new GeoTiffReader(this, source, null); } } return reader; } And the method 'public boolean accepts(Object o)' as follow: public boolean accepts(Object o) { boolean goodfile = false; if (o instanceof CatalogEntry) { o = ((CatalogEntry) o).resource(); } goodfile = o instanceof File; if (goodfile) { goodfile = GeoTiffReader.isGeoTiffFile((File) o); } else if (o instanceof URL) { URL url = (URL) o; try { final String pathname = URLDecoder.decode(url.getFile(),"UTF-8"); goodfile = GeoTiffReader.isGeoTiffFile(new File(pathname)); } catch (Exception e) { goodfile = false; } } return goodfile; }