Documentation images (solves #308) (#335)

* fix incorrect and incomplete coordinate systems (resolves #308)

* add readme to documentation
the readme contains a description of creating and editing vector images

Author: SchreinerKarl

doc/README.md

@@ -0,0 +1,32 @@
+Documentation
+============
+The vector images for the open-simulation-interface documentation are provided in the .svg-format.
+
+## Creating vector images
+Objects such as roads, vehicles, signs, etc. that are embedded in the graphics are based on realistic high detailed 3D models.
+The overall scene and 3D objects are modelled using the 3D modelling software [Blender](https://www.blender.org/).
+The Freestyle SVG Exporter from Blender is used to convert the modelled 3D scene into vector graphics.
+
+The Freestyle SVG Exporter add-on from Blender can be activated via the Render user settings. 
+The GUI for the Exporter is located in the Render tab of the Properties Editor. After rendering, the exported .svg file is written to the output path.
+
+For more information about Blender's Freestyle SVG Exporter add-on see:
+ [docs.blender.org](https://docs.blender.org/manual/en/latest/render/freestyle/export_svg.html)
+
+Following settings are used for exporting:
+Freestyle SVG Export:
+Frame, Round;
+LineThickness = Absolute, 1.000px;
+
+Freestyle Line Set: 
+Visibility = Visible, 
+Edgetype = Inclusive, 
+Silhouette = true,
+Border = true;
+
+## Editing vector images
+
+The exported 3D vector graphics can be opened and edited with any image editing program. (e.g. [Inkscape](https://inkscape.org/de/))
+The vectors and labels are placed accordingly.
+The graphics should generally be kept in a grayscale style.
+RGBA code for grey: b3b3b3ff