diff --git a/hoot-core/src/main/cpp/hoot/core/algorithms/perty/PermuteGridCalculator.h b/hoot-core/src/main/cpp/hoot/core/algorithms/perty/PermuteGridCalculator.h
new file mode 100644
index 0000000..c3fb9a4
--- /dev/null
+++ b/hoot-core/src/main/cpp/hoot/core/algorithms/perty/PermuteGridCalculator.h
@@ -0,0 +1,88 @@
+/*
+ * This file is part of Hootenanny.
+ *
+ * Hootenanny 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.
+ *
+ * This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * --------------------------------------------------------------------
+ *
+ * The following copyright notices are generated automatically. If you
+ * have a new notice to add, please use the format:
+ * " * @copyright Copyright ..."
+ * This will properly maintain the copyright information. DigitalGlobe
+ * copyrights will be updated automatically.
+ *
+ * @copyright Copyright (C) 2015, 2016, 2017, 2018, 2019 DigitalGlobe (http://www.digitalglobe.com/)
+ */
+#ifndef PERMUTE_GRID_CALCULATOR_H
+#define PERMUTE_GRID_CALCULATOR_H
+
+// hoot
+#include <hoot/core/util/OpenCv.h>
+#include <hoot/core/util/Units.h>
+
+// geos
+#include <geos/geom/Envelope.h>
+
+// Qt
+#include <QString>
+
+namespace hoot
+{
+
+/**
+ *
+ */
+class PermuteGridCalculator
+{
+public:
+
+ static std::string className() { return "hoot::PermuteGridCalculator"; }
+
+ virtual ~PermuteGridCalculator() { }
+
+ /**
+ * Calculates a permutation grid and the values in that grid for a given envelope. The number of
+ * rows and columns are returned in rows and cols.
+ */
+ virtual cv::Mat permute(geos::geom::Envelope env, int& pointRows, int& pointCols) = 0;
+
+ /**
+ * Seeds the permutation process. By default a seed is generated based on time. The seed should
+ * be non-negative or -1 to generate a seed based on time.
+ */
+ void setSeed(int seed) { _seed = seed; }
+
+ /**
+ * Sets the systematic error. This is the sigma value for Sx and Sy. The same sigma value is used
+ * for all values in each matrix. See [1] for more information.
+ */
+ void setSystematicError(Meters sigmaX, Meters sigmaY) { _sigmaSx = sigmaX; _sigmaSy = sigmaY; }
+
+ void setCsmParameters(double D) { _D = D; }
+
+ void setGridSpacing(Meters gridSpacing) { _gridSpacing = gridSpacing; }
+
+ virtual QString toString();
+
+protected:
+
+ Meters _D;
+ Meters _gridSpacing;
+ int _seed;
+ Meters _sigmaSx, _sigmaSy;
+};
+
+}
+
+#endif // PERMUTE_GRID_CALCULATOR_H