Handle case that target WKT is null

Author: Tom Brauer

vortex-api/src/main/java/mil/army/usace/hec/vortex/geo/Resampler.java

@@ -92,8 +92,15 @@ public VortexGrid resample(){
             envSrs = new SpatialReference();
         }
 
-        SpatialReference destSrs = new SpatialReference(targetWkt);
-        destSrs.MorphFromESRI();
+        Dataset dataset = RasterUtils.getDatasetFromVortexGrid(subset);
+
+        SpatialReference destSrs = new SpatialReference();
+        if (targetWkt != null) {
+            destSrs.ImportFromWkt(targetWkt);
+            destSrs.MorphFromESRI();
+        } else {
+            destSrs.ImportFromWkt(dataset.GetProjection());
+        }
 
         Dataset dataset = RasterUtils.getDatasetFromVortexGrid(grid);
         Dataset resampled = resample(dataset, env, envSrs, destSrs, cellSize, method);