How to create new lithologies/symbols

SedLog allows the user to import new lithologies and symbols in SVG/SVGZ format (see Add new litholgies/symbols to SedLog). SVG (Scalable Vector Graphics) is an XML specification and file format for describing two-dimensional vector graphics, both static and animated. It is an open standard created by the World Wide Web Consortium's SVG Working Group. SVGZ are compessed SVG files.

You can create your own SVG/SVGZ files by using a vector graphics software such as Inkscape, CorelDraw, Adobe Illustrator, Adobe Photoshop etc. Inkscape is a free and open source vector graphics editor application. Its stated goal is to become a powerful graphic tool while being fully compliant with the XML, SVG and CSS standards. Inkscape is primarily developed for Linux, but it is cross-platform and runs on Mac OS X (under X11), other Unix-like operating systems, and Microsoft Windows. Inkscape has multi-lingual support, particularly for complex scripts, something currently lacking in most commercial vector graphics applications. You can download
Inkscape from: www.inkscape.org.

SVG/SVGZ format is a vector graphics image format as opposed to a raster graphics image. Computers can store images either: a) as a raster graphics image or bitmap, or b) as a vector graphics image. Bitmaps are matrices of pixels and appear jagged when rescaled or printed. Vector graphics use geometrical primitives such as points, lines, curves, and polygons to represent images and continue to look the same when rescaled or printed.
Examples of raster graphics image or bitmap file formats are: JPEG, GIF, BMP and PNG. Examples of vector graphics image formats are: SVG/SVGZ, PDF, EPS/PS, AI(Adobe Illustrator) and CorelDraw.

You can use also
Inkscape to convert patterns or symbols saved in other formats such as AI, PDF, JPEG, GIF, BMP, PNG, etc to SVG or SVGZ. If the file you want to convert is a bitmap (raster image) then first you have to use Inkscape to converted it to vector format before you save it as SVG. To do this first open the bitmap using Inkscape. Then select the loaded bitmap by clicking the Select All option from the Edit menu. From the Path menu select Trace Bitmap (see figure 1 below). A dialog box with various options will appear (see figure 2 below). Select the Colors option (if you not select this option the resulting image will be black and white) and press OK. The vector version of the image will be created on top of the original bitmap image. Select the vector version and move it a little to reveal the original (bitmap). Select the bitmap and remove it. Save the image as SVG. You may need to play around with various options until you get it right. 




Figure 1.




Figure 2.

NOTE: Make sure that the bitmap you provide is not to small. The bigger the bitmap the better the results of the tracing will be. To rescale or modify a bitmap you can use GIMP (GNU Image Manipulation Program) a free cross-platform software for editing and creating raster images. You can download GIMP from: www.gimp.org

For more information how to use Inkscape please consult the Inkscape manual.


See Also

Add new litholgies/symbols to SedLog