Fixed issues with GisGeometry/Strategy classes. Addresses DOI-USGS#5612.

* GisGeometry was throwing an exception when isValid() was called and the geometry was indeed invalid
* GisGeometry - added buffer() method
* Strategy was updated to better manage geometries
* Strategy - Added RepairInvalidGeometry and InvalidGeometryAction to allow better user control over invalid geometries
* Strategy - Apply buffer(0) algorithm when an invalid geometry is detected
* Strategy - Added more debug output

isis/src/base/objs/GisGeometry/GisGeometry.cpp

@@ -207,15 +207,25 @@ namespace Isis {
    *
    *  First determines if it contains a geometry and then validates with the
    *  GEOS toolkit.
-   *
-   * @return bool True if valid, false if invalid or non-existant
-   */
+   *  
+   * @return bool True if valid, false if invalid or non-existant 
+   *  
+   * @history 2018-07-29 Kris Becker - If the geometry is invalid, it throws an 
+   *                        exception. Catch all exceptions an return proper
+   *                        status
+   */  
   bool GisGeometry::isValid() const {
     if (!isDefined()) {
       return (false);
     }
-
-    return (1 == GEOSisValid(this->m_geom));
+
+    int valid(0);
+    try {
+        valid = GEOSisValid(this->m_geom);
+    } catch (...) {
+        valid = 0;
+    }
+    return (1  == valid);
   }
 
 
@@ -601,9 +611,35 @@ namespace Isis {
     double ratio = inCommon->area() / this->area();
     return (ratio);
   }
+
 
-
-  /**
+/**
+ * @brief Compute a buffer around an existing geometry 
+ *  
+ * Add a buffer around a geometry with the defined enlargement factor. It is 
+ * common to use this as buffer(0) to fix geometries with self-intersections. 
+ * These cases are often identified by calling isValid() and getting a false 
+ * value returned. 
+ * 
+ * @author 2018-07-29 Kris Becker
+ * 
+ * @param width    With to enlarge or shrink polygon 
+ * @param quadsegs Numnber of segments to define a circle on corners
+ * 
+ * @return GisGeometry* Pointer to new GisGeometry with buffer applied
+ */
+  GisGeometry *GisGeometry::buffer(const double width,const int quadsegs) const {
+      // If there is no geometry, return a null geometry
+      if ( !isDefined()) {
+          return (new GisGeometry());
+      }
+
+    // Create the buffer around the geom
+    GEOSGeometry *geom = GEOSBuffer(m_geom, width, quadsegs);
+    return (new GisGeometry(geom));
+  }
+
+  /** 
    * @brief Computes the envelope or bounding box of this geometry
    *
    * This method computes the envelope or bounding box of the geometry in this

isis/src/base/objs/GisGeometry/GisGeometry.h

@@ -46,6 +46,11 @@ namespace Isis {
    *                           ISIS. Fixes #2398.
    *   @history 2016-03-04 Kris Becker - Completed the documentation and implmented the equals()
    *                           method.
+   *   @history 2018-07-29 Kris Becker - Added buffer() method; isValid() was
+   *                           throwing an exception if the geometry was invalid
+   *                           (e.g., self-intersecting geometry), which is now
+   *                           trapped and a false condition is properly returned.
+   * 
    */   
   class GisGeometry {
 
@@ -99,6 +104,7 @@ namespace Isis {
 
       double intersectRatio(const GisGeometry &geom) const;
 
+      GisGeometry *buffer(const double width=0.0, const int quadsegs=16) const;
       GisGeometry *envelope( ) const;
       GisGeometry *convexHull( ) const;
       GisGeometry *simplify(const double &tolerance) const;

isis/src/base/objs/Strategy/Strategy.cpp

@@ -725,7 +725,18 @@ namespace Isis {
 
     // Got a geometry.
     if ( !geom.isEmpty() ) {
-
+
+        // Get decision keys
+        bool repairGeom = toBool(keys.get("RepairInvalidGeometry", "true"));
+        QString geomAction = keys.get("InvalidGeometryAction", "disable").toLower();
+        if ( !QString("disable error continue").contains(geomAction) ) {
+            if ( isDebug() ) {
+              cout << "  Invalid value for InvalidGeometryAction (" << geomAction 
+                   << ") - set to disable!\n";
+            }
+            geomAction = "disable";
+        }
+
       //  Process arguments  Allows creation specialized geometry as well
       if ( keys.exists("GisGeometryArgs") ) {
         QStringList args = keys.allValues("GisGeometryArgs");
@@ -743,7 +754,65 @@ namespace Isis {
       if ( !geom.isEmpty() ) {
 
         QScopedPointer<GisGeometry> geosgeom(new GisGeometry(geom, GisGeometry::type(gisType)));
-        if ( geosgeom.isNull() || !geosgeom->isValid() ) return (false);
+        if ( geosgeom.isNull() ) {
+            if ( isDebug() ) {
+                cout << resource->name() << " geometry failed to construct\n";
+            }
+            if ("continue" == geomAction) return (false);
+            if ( "disable" == geomAction ) {
+                resource->discard();
+                return ( false );
+            }
+
+            // Throw an error
+            QString mess = resource->name() + " failed to construct geometry!";
+            throw IException(IException::Programmer, mess, _FILEINFO_);
+        }
+
+        // Check validity and take appropriate action
+        if ( !geosgeom->isValid() ) {
+
+          QString geomError = geosgeom->isValidReason();
+          if ( isDebug() ) {
+              cout << "  Geometry error: " << geomError << "\n";
+          }
+
+          // Attempt repair if requested
+          if ( repairGeom ) {
+            if (isDebug()) {
+              cout << "  " << resource->name() << " geometry is invalid..."
+                    << "attempting buffer(0) to fix it!\n";
+            }
+            geosgeom.reset( geosgeom->buffer(0) );
+            if ( isDebug() ) {
+              if (geosgeom.isNull() || !geosgeom->isValid() ) {
+                 cout << "  Geomtry could not be repaired!\n";
+              }
+              else {
+                cout << "  Geometry was successfully repaired!\n";
+              }
+            }
+          }
+
+          // Now check state and take final action regarding a failed
+          // geometry 
+
+          if (geosgeom.isNull() || !geosgeom->isValid() ) {
+            if ( isDebug() ) {
+                cout << "  All efforts to convert geometry failed!\n";
+            }
+            if ("continue" == geomAction) return (false);
+            if ( "disable" == geomAction ) {
+              resource->discard();
+              return ( false );
+            }
+
+            // Throw an error
+            QString mess = resource->name() + " failed to construct geomtry - Error: " +
+                            geomError;
+            throw IException(IException::Programmer, mess, _FILEINFO_);
+          }
+        }
 
         npointsOrg =  npoints = geosgeom->points();
         QString gisTolerance  = translateKeywordArgs("GisSimplifyTolerance", 

isis/src/base/objs/Strategy/Strategy.h

@@ -15,6 +15,7 @@ find files of those names at the top level of this repository. **/
 #include <QString>
 
 // SharedResource and ResourceList typedefs
+#include "GisGeometry.h"
 #include "Resource.h"
 #include "PvlObject.h"
 
@@ -80,6 +81,12 @@ namespace Isis {
    *                          replacements in reverse order fixes this issue.
    * @history 2016-03-07  Tyler Wilson - Corrected documentation, and created a
    *                          unit test to test most of this classe's methods.
+   * @history 2018-07-29 Kris Becker - Fixed errors in importGeometry() where an 
+   *                          exception was being thrown when checking for valid
+   *                          Geometry. It now checks for this case and runs
+   *                          buffer(0) to attempt to fix the geometry. This is
+   *                          typically a self-intersection error that can be
+   *                          repaired with a buffer(0) operator.
    */
 
   class Strategy {