Preserve scale and offset when processing las file

point_io.cpp

@@ -314,6 +314,40 @@ PointSet *fastPlyReadPointSet(const std::string &filename) {
     return r;
 }
 
+#ifdef WITH_PDAL
+template <typename T>
+bool pdalReadLasMeta(pdal::MetadataNode &lasforward, std::string name, T &val) {
+    pdal::MetadataNode m = lasforward.findChild(name);
+    if (m.valid()) {
+        val = m.value<T>();
+        return true;
+    } else {
+        return false;
+    }
+}
+
+void pdalReadLasScaleOffset(pdal::PointTable *table, PointSet *pSet) {
+    pdal::MetadataNode lasforward;
+    lasforward = table->privateMetadata("lasforward");
+    if (!lasforward.valid())
+        return;
+    bool success = true;
+    pSet->scales = std::make_unique<std::array<double, 3>>();
+    success &= pdalReadLasMeta(lasforward, "scale_x", pSet->scales->at(0));
+    success &= pdalReadLasMeta(lasforward, "scale_y", pSet->scales->at(1));
+    success &= pdalReadLasMeta(lasforward, "scale_z", pSet->scales->at(2));
+    if (!success)
+        pSet->scales = nullptr;
+    success = true;
+    pSet->offsets = std::make_unique<std::array<double, 3>>();
+    success &= pdalReadLasMeta(lasforward, "offset_x", pSet->offsets->at(0));
+    success &= pdalReadLasMeta(lasforward, "offset_y", pSet->offsets->at(1));
+    success &= pdalReadLasMeta(lasforward, "offset_z", pSet->offsets->at(2));
+    if (!success)
+        pSet->offsets = nullptr;
+}
+#endif
+
 PointSet *pdalReadPointSet(const std::string &filename) {
     #ifdef WITH_PDAL
     std::string labelDimension;
@@ -336,6 +370,10 @@ PointSet *pdalReadPointSet(const std::string &filename) {
     s->prepare(*table);
     const pdal::PointViewSet pvSet = s->execute(*table);
 
+    if (driver == "readers.las") {
+        pdalReadLasScaleOffset(table, r);
+    }
+
     r->pointView = *pvSet.begin();
     const pdal::PointViewPtr pView = r->pointView;
 
@@ -492,6 +530,18 @@ void pdalSavePointSet(PointSet &pSet, const std::string &filename) {
     pdal::Stage *s = factory.createStage(driver);
     pdal::Options opts;
     opts.add("filename", filename);
+    if (driver == "writers.las") {
+        if (pSet.scales != nullptr) {
+            opts.add("scale_x", pSet.scales->at(0));
+            opts.add("scale_y", pSet.scales->at(1));
+            opts.add("scale_z", pSet.scales->at(2));
+        }
+        if (pSet.offsets != nullptr) {
+            opts.add("offset_x", pSet.offsets->at(0));
+            opts.add("offset_y", pSet.offsets->at(1));
+            opts.add("offset_z", pSet.offsets->at(2));
+        }
+    }
     s->setOptions(opts);
     s->setInput(reader);
 

point_io.hpp

@@ -40,6 +40,8 @@ struct PointSet {
 
     #ifdef WITH_PDAL
     pdal::PointViewPtr pointView = nullptr;
+    std::unique_ptr<std::array<double, 3>> scales = nullptr;
+    std::unique_ptr<std::array<double, 3>> offsets = nullptr;
     #endif
 
     template <typename T>