Add support for string to/from dimension type conversion.

io/GDALWriter.cpp

@@ -68,6 +68,8 @@ void GDALWriter::addArgs(ProgramArgs& args)
         m_options);
     args.add("output_type", "Statistics produced ('min', 'max', 'mean', "
         "'idw', 'count', 'stdev' or 'all')", m_outputTypeString, {"all"} );
+    args.add("data_type", "Data type for output grid (\"int8\", \"uint64\", "
+        "\"float\", etc.)", m_dataType);
     args.add("window_size", "Cell distance for fallback interpolation",
         m_windowSize);
     args.add("nodata", "No data value", m_noData, -9999.0);

io/GDALWriter.hpp

@@ -86,6 +86,7 @@ class PDAL_DLL GDALWriter : public FlexWriter
     double m_noData;
     Dimension::Id m_interpDim;
     std::string m_interpDimString;
+    Dimension::Type m_dataType;
 };
 
 }

pdal/DimUtil.hpp

@@ -170,7 +170,6 @@ inline Type type(std::string s)
     return Type::None;
 }
 
-
 /// Extract a dimension name of a string.  Dimension names start with an alpha
 /// and continue with numbers or underscores.
 /// \param s  String from which to extract dimension name.
@@ -187,6 +186,24 @@ inline std::size_t extractName(const std::string& s, std::string::size_type p)
     return Utils::extract(s, p, isvalid) + 1;
 }
 
+inline std::istream& operator>>(std::istream& in, Dimension::Type& type)
+{
+    std::string sval;
+
+    in >> sval;
+    type = Dimension::type(sval);
+    if (type == Dimension::Type::None)
+        in.setstate(std::ios_base::failbit);
+    return in;
+}
+
+inline std::ostream& operator<<(std::ostream& out, const Dimension::Type& type)
+{
+    out << Dimension::interpretationName(type);
+    return out;
+}
+
 } // namespace Dimension
+
 } // namespace pdal