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 compressed SVG files

You can create your own SVG/SVGZ files by using graphics software such as Inkscape, CorelDraw, Adobe Illustrator, etc.

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.

Inkscape is a free and open source vector graphics editor application. Itsstated 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 runson Mac OS X (under X11), other Unix-like operating systems, and Microsoft Windows. Inkscape has multi-lingual support, particularly for complex scripts, somethingcurrently lacking in most commercial vector graphics applications. You can download Inkscape from: https://inkscape.org/en/ or www.inkscape.org

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 too 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.

Troubleshooting

Some comments on SVG files:


CorelDraw

We have previously used CorelDraw successfully, but not X5. SedLog will not recognise the CorelDraw X5 SVGZ format. It does recognise the X5 SVG format but does not show the ornament. There are several options in X5 that allow you to alter settings when creating the SVG/Z format but we have altered several without success.


Adobe Illustrator

This successfully created both SVG and SVGZ files that SedLog was able to read. I compared settings for the SVG file by opening it in a text editor, and also looked at the settings defined by Illustrator. They appear to be the same as CorelDraw is using, so why CorelDraw fails and Illustrator succeeds is not clear.

Users of Adobe Illustrator CS6 suggest you should reduce the size of the artboard so that it is the same size as (or only slightly larger than) the symbol graphic. It also looks like the maximum size for an SVG image to fit the entire symbol is about 42x42 pixels, but to match the existing symbols 20x20 px is a good size


Inkscape

The SVG file (the default format) worked perfectly. The SVGZ file this worked perfectly too. When saving include the extension (.svg/.svgz) in the file name or the file did not seem to appear. Inkscape is a good solution – it works and is free.


Errors

Some users have reported an error when trying to import new symbols into SedLog 3.1, "Unable to read this file: <filepath.svg>."

To solve this problem, you can download and run the installer again, but first do the following:

1. right-click on the installer file (sedlog-3.1-setup.exe),

2. select the "Compatibility" tab,

3. check the box "Run this program in compatibility mode for:" and select "Windows XP (Service Pack 3),"

4. check the box "Run this program as an administrator."

Run the installer. You should now be able to create and import SVG graphics using the instructions.


See Also

Add new litholgies/symbols to SedLog