Accept GDAL options and pass to driver on dataset creation.

include/pdal/GDALUtils.hpp

@@ -250,6 +250,7 @@ enum class GDALError
     InvalidDriver,
     DriverNotFound,
     CantCreate,
+    InvalidOption,
     CantWriteBlock
 };
 
@@ -296,9 +297,10 @@ class PDAL_DLL Raster
       \param numBands  Number of bands in the raster.
       \param type  Datatype (int, float, etc.) of the raster data.
       \param noData  Value that indiciates no data in a raster cell.
+      \param options  GDAL driver options.
     */
     GDALError open(int width, int height, int numBands, Dimension::Type type,
-        double noData);
+        double noData, StringList options = StringList());
 
     /**
       Close the raster and deallocate the underlying dataset.

io/gdal/GDALWriter.cpp

@@ -65,6 +65,8 @@ void GDALWriter::addArgs(ProgramArgs& args)
     args.add("radius", "Radius from cell center to use to locate influencing "
         "points", m_radius).setPositional();
     args.add("gdaldriver", "GDAL writer driver name", m_drivername, "GTiff");
+    args.add("gdalopts", "GDAL driver options (name=value,name=value...)",
+        m_options);
 }
 
 
@@ -130,7 +132,7 @@ void GDALWriter::done(PointTableRef table)
     raster.writeBand(m_grid->data("mean"), 3, "mean");
     raster.writeBand(m_grid->data("idw"), 4, "idw");
     raster.writeBand(m_grid->data("count"), 5, "count");
-    raster.writeBand(m_grid->data("den"), 6, "den");
+    raster.writeBand(m_grid->data("stdev"), 6, "stdev");
 }
 
 } // namespace pdal

io/gdal/GDALWriter.hpp

@@ -90,7 +90,7 @@ class Grid
             return (uint8_t *)m_mean.data();
         if (name == "idw")
             return (uint8_t *)m_idw.data();
-        if (name == "den")
+        if (name == "stdev")
             return (uint8_t *)m_stdDev.data();
         throw pdal_error("Requested invalid grid data '" + name + "'.");
     }
@@ -189,6 +189,10 @@ class Grid
 
     void update(int x, int y, double val, double dist)
     {
+        // See
+        // https://en.wikipedia.org/wiki/Algorithms_for_calculating_variance
+        // https://en.wikipedia.org/wiki/Inverse_distance_weighting
+
         size_t offset = (y * m_width) + x;
 
         double& count = m_count[offset];
@@ -217,6 +221,9 @@ class Grid
 
     void finalize()
     {
+        // See
+        // https://en.wikipedia.org/wiki/Algorithms_for_calculating_variance
+        // https://en.wikipedia.org/wiki/Inverse_distance_weighting
         for (size_t i = 0; i < m_count.size(); ++i)
         {
             if (m_count[i])
@@ -273,6 +280,7 @@ class PDAL_DLL GDALWriter : public Writer
     BOX2D m_bounds;
     double m_edgeLength;
     double m_radius;
+    StringList m_options;
     GridPtr m_grid;
 };
 

src/GDALUtils.cpp

@@ -491,7 +491,7 @@ Raster::Raster(const std::string& filename, const std::string& drivername,
 
 
 GDALError Raster::open(int width, int height, int numBands,
-    Dimension::Type type, double noData)
+    Dimension::Type type, double noData, StringList options)
 {
     if (m_drivername.empty())
         m_drivername = "GTiff";
@@ -527,9 +527,22 @@ GDALError Raster::open(int width, int height, int numBands,
         return GDALError::InvalidDriver;
     }
 
-    const char *options[2] = { "INTERLEAVE=BAND" };
+    std::vector<const char *> opts;
+
+    for (size_t i = 0; i < options.size(); ++i)
+    {
+        if (options[i].find("INTERLEAVE") == 0)
+        {
+            m_errorMsg = "INTERLEAVE GDAL driver option not supported.";
+            return GDALError::InvalidOption;
+        }
+        opts.push_back(options[i].data());
+    }
+    opts.push_back("INTERLEAVE=BAND");
+    opts.push_back(NULL);
+
     m_ds = driver->Create(m_filename.data(), m_width, m_height, m_numBands,
-        toGdalType(type), (char **)options);
+        toGdalType(type), const_cast<char **>(opts.data()));
     if (m_ds == NULL)
     {
         m_errorMsg = "Unable to open GDAL datasource '" + m_filename + "'.";