FANDOM


Here we go, I've made a start. I have decided upon the highest resolution image of Tamriel I could find, which is this one...

400px-Temp_file_5749948_1356233009.jpeg

The full sized image is 2560x1440 pixels, at 4.3MB in size. Sure, it's not a large as the one I mentioned in my previous post, but that one also includes more ocean and outlying islands, which ultimately reduces the resolution of Tamriel itself. Here is the raster image loaded as a layer in Qunatum GIS...

400px-Screenshot1_raster_layer.png

Those who use QGIS will notice that I have only got the digitizing tools on my toolbar for now, along with the Improved Polygon Capturing v1.0 plugin toolbar. This plugin allows me to easily add parts to a polygon feature, such as Vvardenfell to Morrowind, or City Isle to Cyriodiil, without needing invisible join lines.

The next step was to add a new vector layer to my QGIS project, and to digitize very rough polygons for the provinces of Tamriel. The underlying attributes are currently just the province name and the race that hails from it. Here is a sample of the rough polygons, showing the area arounf City Isle in Cyrodiil...

400px-Temp_file_5749948_1356234739.png

As you can see, the polygons so far are extremely rough, not following the coastlines that closely at all. The next step, and one of the most time-consuming steps, is to tidy up these polygons. There are many problems the amateur cartographer encounters during the digitizing step. Most of them are caused by the resolution of the raster image. Here is an example...

400px-Screenshot3_digitizing_issues.png

For a start, if the source raster image contains bitmapped text, such as the above example, it can often alter the coastline where a text character intersects with the coastline. Also, artifacting in a compressed JPEG image can make it difficult to know where the edge of the coastline is. Furthermore, the width of the outline of the coastline can prove to be confusing: do I digitize to the edge of the bold, black line, or do I digitize to the center of it? Finally, how many points should I add along each segment of the polygon? Should I add a point for each pixel, or for each logical segment, or for each side of each pixel? The more you zoom in on the raster image, the more you realize just how far off your digitizing is.

Here is a zoomed-in version, showing that I have decided on digitizing each side of each pixel. Now the problem is, how dark does a pixel have to be before it is deemed "land" instead of "water"? This is a great example of the problem I had mentioned above, about artifacts and anti-aliasing in a JPEG or bitmap image...

400px-Screenshot4_aliasing.png

Today I have spent quite a lot of time digitizing the coastline of my new map. Here are the results so far. In the image below, the closer the red X handles are together, the tidier the coastline will be. Places where the red X handles are closer together show where I have been working on my map today...

400px-Screenshot6_progress_so_far.png

When you hide the background raster image, and the node editing handles, you end up with something like this...

400px-Screenshot7_progress_so_far.png

As you can see, it is huggely time-consuming. I've barely finished off the the coasts of Lake Rumare and City Isle in Cyrodiil, let alone the rest of Tamriel. I have spent probably 6 hours on this so far today, since begining the project in Quantum GIS.