TopoJSON: do not advertize Z capabilities

Author: rouault

ogr/ogrsf_frmts/geojson/ogr_geojson.h

@@ -132,6 +132,11 @@ class OGRGeoJSONLayer final : public OGRMemLayer
         m_bSupportsMGeometries = bSupportsMGeometries;
     }
 
+    void SetSupportsZGeometries(bool bSupportsZGeometries)
+    {
+        m_bSupportsZGeometries = bSupportsZGeometries;
+    }
+
   private:
     OGRGeoJSONDataSource *poDS_;
     OGRGeoJSONReader *poReader_;
@@ -141,6 +146,7 @@ class OGRGeoJSONLayer final : public OGRMemLayer
     GIntBig nTotalFeatureCount_;
     GIntBig nFeatureReadSinceReset_ = 0;
     bool m_bSupportsMGeometries = false;
+    bool m_bSupportsZGeometries = true;
 
     //! Write options used by ICreateFeature() in append scenarios
     OGRGeoJSONWriteOptions oWriteOptions_;
@@ -303,6 +309,11 @@ class OGRGeoJSONDataSource final : public GDALDataset
         m_bSupportsMGeometries = bSupportsMGeometries;
     }
 
+    void SetSupportsZGeometries(bool bSupportsZGeometries)
+    {
+        m_bSupportsZGeometries = bSupportsZGeometries;
+    }
+
     virtual CPLErr FlushCache(bool bAtClosing) override;
 
     CPLErr Close() override;
@@ -339,6 +350,8 @@ class OGRGeoJSONDataSource final : public GDALDataset
     CPLString osJSonFlavor_;
 
     bool m_bSupportsMGeometries = false;
+    bool m_bSupportsZGeometries = true;
+
     //
     // Private utility functions
     //

ogr/ogrsf_frmts/geojson/ogrgeojsondatasource.cpp

@@ -755,7 +755,7 @@ int OGRGeoJSONDataSource::TestCapability(const char *pszCap)
     else if (EQUAL(pszCap, ODsCMeasuredGeometries))
         return m_bSupportsMGeometries;
     else if (EQUAL(pszCap, ODsCZGeometries))
-        return TRUE;
+        return m_bSupportsZGeometries;
 
     return FALSE;
 }

ogr/ogrsf_frmts/geojson/ogrgeojsonlayer.cpp

@@ -507,7 +507,7 @@ int OGRGeoJSONLayer::TestCapability(const char *pszCap)
     else if (EQUAL(pszCap, OLCMeasuredGeometries))
         return m_bSupportsMGeometries;
     else if (EQUAL(pszCap, OLCZGeometries))
-        return TRUE;
+        return m_bSupportsZGeometries;
     else if (EQUAL(pszCap, OLCStringsAsUTF8))
         return TRUE;
     else if (EQUAL(pszCap, OLCFastGetExtent) ||

ogr/ogrsf_frmts/geojson/ogrtopojsonreader.cpp

@@ -495,6 +495,7 @@ ParseObjectMain(const char *pszId, json_object *poObj,
                     OGRGeoJSONLayer *poLayer =
                         new OGRGeoJSONLayer(pszId ? pszId : "TopoJSON", nullptr,
                                             wkbUnknown, poDS, nullptr);
+                    poLayer->SetSupportsZGeometries(false);
                     OGRFeatureDefn *poDefn = poLayer->GetLayerDefn();
 
                     const auto nGeometries =
@@ -569,6 +570,9 @@ ParseObjectMain(const char *pszId, json_object *poObj,
                 {
                     *ppoMainLayer = new OGRGeoJSONLayer(
                         "TopoJSON", nullptr, wkbUnknown, poDS, nullptr);
+
+                    (*ppoMainLayer)->SetSupportsZGeometries(false);
+
                     apoFieldDefn.emplace_back(
                         std::make_unique<OGRFieldDefn>("id", OFTString));
                     oMapFieldNameToIdx["id"] = 0;
@@ -629,6 +633,8 @@ void OGRTopoJSONReader::ReadLayers(OGRGeoJSONDataSource *poDS)
         return;
     }
 
+    poDS->SetSupportsZGeometries(false);
+
     ScalingParams sParams;
     sParams.dfScale0 = 1.0;
     sParams.dfScale1 = 1.0;