diff --git a/opm/core/utility/DataMap.hpp b/opm/core/utility/DataMap.hpp
new file mode 100644
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--- /dev/null
+++ b/opm/core/utility/DataMap.hpp
@@ -0,0 +1,32 @@
+/*
+  Copyright 2012 SINTEF ICT, Applied Mathematics.
+
+  This file is part of the Open Porous Media project (OPM).
+
+  OPM is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  OPM is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef OPM_DATAMAP_HEADER_INCLUDED
+#define OPM_DATAMAP_HEADER_INCLUDED
+
+#include <string>
+#include <map>
+
+namespace Opm
+{
+  /// Intended to map strings (giving the output field names) to data.
+  typedef std::map<std::string, const std::vector<double>*> DataMap;
+}
+
+#endif