diff --git a/src/main/java/eu/simstadt/regionchooser/RegionChooserCommandLineInterface.java b/src/main/java/eu/simstadt/regionchooser/RegionChooserCommandLineInterface.java
index fb6469cbe05cba8347b05c697fc330a7f4fc0edb..abab71d4bfe57239cf2acc150b17fa15fc9c7d59 100644
--- a/src/main/java/eu/simstadt/regionchooser/RegionChooserCommandLineInterface.java
+++ b/src/main/java/eu/simstadt/regionchooser/RegionChooserCommandLineInterface.java
@@ -6,11 +6,19 @@
 import java.nio.file.Paths;
 import java.util.Scanner;
 import java.util.concurrent.Callable;
+import org.locationtech.jts.geom.Polygon;
+import org.locationtech.jts.io.WKTReader;
+import org.locationtech.jts.io.WKTWriter;
 import org.osgeo.proj4j.CoordinateReferenceSystem;
 import picocli.CommandLine;
 import picocli.CommandLine.Command;
 import picocli.CommandLine.Option;
 
+// Example usage:
+// --input /home/ricou/Desktop/CGSC_Repository/Würzburg.proj/LoD2_566_5516_2_BY.gml,/home/ricou/Desktop/CGSC_Repository/Würzburg.proj/LoD2_568_5516_2_BY.gml
+// --output /home/ricou/Desktop/output.gml
+// --wkt /home/ricou/Desktop/grombuhl.txt
+
 
 @Command(name = "region_chooser", mixinStandardHelpOptions = true, version = "regionChooser x.x", description = "Extracts a region from one or more citygmls.", sortOptions = false)
 class RegionChooserCommandLineInterface implements Callable<Integer>
@@ -36,6 +44,8 @@ class RegionChooserCommandLineInterface implements Callable<Integer>
 
 	@Override
 	public Integer call() throws Exception {
+		//TODO: Move as much logic to utils as possible, and test it.
+		//TODO: Use logger
 		CoordinateReferenceSystem localCRS;
 
 		if (espgId == null) {
@@ -43,6 +53,7 @@ public Integer call() throws Exception {
 		} else {
 			localCRS = RegionChooserUtils.crsFromSrsName("EPSG:" + espgId);
 		}
+		System.out.println("Coordinate system is " + localCRS);
 
 		String wktPolygon;
 
@@ -60,13 +71,20 @@ public Integer call() throws Exception {
 		}
 
 		if (!localCoordinates) {
+			final WKTReader WKT_READER = new WKTReader();
+			final WKTWriter WKT_WRITER = new WKTWriter();
 			// WKT coordinates are in WGS84, so should be first converted to srsName
+			Polygon wgs84Polygon = (Polygon) WKT_READER.read(wktPolygon);
+			wktPolygon = WKT_WRITER
+					.write(RegionChooserUtils.changePolygonCRS(wgs84Polygon, RegionChooserUtils.WGS84, localCRS));
 		}
 
 		System.out.println("WKT Polygon : " + wktPolygon);
 
 		StringBuilder sb = RegionExtractor.selectRegionDirectlyFromCityGML(wktPolygon, localCRS.toString(), citygmls);
 
+		//TODO: Check how many buildings are written. Warning if 0?
+
 		RegionChooserUtils.writeStringBuilderToFile(sb, outputCityGML);
 
 		return 0;