Merge pull request #1383 from orbisgis/shapefile_empty_geom

Shapefile save empty geometry as null geometry

docs/CHANGELOG.md

@@ -1,3 +1,4 @@
 ## Changelog for v2.2.2
 - Read CPG file attached to the shapefile- 
-- Declare the schema for the spatial_ref_sys table
+- Declare the schema for the spatial_ref_sys table
+- Write empty geometry with the shapefile driver

h2gis-functions/src/main/java/org/h2gis/functions/io/shp/internal/ShapefileWriter.java

@@ -158,7 +158,7 @@ public void writeGeometry(Geometry g) throws IOException {
         shapeBuffer.putInt(++cnt);
         shapeBuffer.putInt(length);
         shapeBuffer.order(ByteOrder.LITTLE_ENDIAN);
-        if (g == null) {
+        if (g == null || g.isEmpty()) {
             shapeBuffer.putInt(0);
         } else {
             shapeBuffer.putInt(type.id);

h2gis-functions/src/test/java/org/h2gis/functions/io/shp/SHPEngineTest.java

@@ -34,6 +34,8 @@
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.Statement;
+
+import static org.h2gis.unitTest.GeometryAsserts.assertGeometryEquals;
 import static org.junit.jupiter.api.Assertions.*;
 
 /**
@@ -450,6 +452,23 @@ public void linkedShpSpatialIndexFlatQueryTest() throws SQLException {
         }
     }
 
+    @Test
+    public void exportImportEmptyGeometry() throws SQLException {
+        Statement stat = connection.createStatement();
+        stat.execute("DROP TABLE IF EXISTS GEOTABLE");
+        stat.execute("create table GEOTABLE(idarea int primary key, the_geom GEOMETRY(POINT))");
+        stat.execute("insert into GEOTABLE values(1, 'POINT (0 0)'::GEOMETRY),(2, 'POINT EMPTY'::GEOMETRY);");
+        // Create a shape file using table area
+        stat.execute("CALL SHPWrite('target/points_withempty.shp', 'GEOTABLE', true)");
+        stat.execute("CALL SHPRead('target/points_withempty.shp', 'IMPORT_GEOTABLE')");
+        ResultSet res = stat.executeQuery("SELECT THE_GEOM FROM IMPORT_GEOTABLE ORDER BY idarea;");
+        res.next();
+        assertGeometryEquals("POINT(0 0)", res.getObject(1));
+        res.next();
+        assertNull(res.getObject(1));
+        res.close();
+    }
+
     @Test
     public void readSHPWithCPGFileTest() throws SQLException {
         Statement st = connection.createStatement();