I thought so.
In this thread I will show you exactly how to do this by providing you with information gathered from the top experts in this field.
As such please Do NOT post your maps in this thread!
Note: After some of the recent updates and the announcement of GW2 I've decided to move to Lord of the Rings Online as I tried it in beta and it's pretty cool. If you do see me on it will just be me popping in, but don't be shy, say hello. ^_^
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In Cantha there will be areas that have fog on them that seem like you should be able to uncover, but you won't be able to. That's ok. You only need to uncover the areas that you can uncover; you won't be able to unfog the entire map. Thus the first step in becoming a Grandmaster Cartographer is of course to clear the fog from as much of the map as you can without having to hunt around for specific spots. There are a few keys to achieving this:
1) Hug the walls!!! Every single area you go to, including outposts. Hug the Walls! This means that you need to travel around the edge of each and every area you come to. So you are basically tracing an outline of the border of each area. This will not only uncover most of the fog within the area, it will also uncover bits of fog that are outside of the explorable area. Most areas that people miss are found by extreme wall hugging. So no matter what area you are in, grab a wall and show it some love.
2) Make sure that you enter every mission area to explore within it's borders. This includes places like Fort Aspen, The Jade Quarry, The Aurios Mines, Amatz Basin, Zos Shivros Channel, and Altrumm Ruins. The only one you don't have to worry about is the Dragon's Throat, but you still need to explore the outpost and surrounding areas.
3) Hug The Walls!!!
4) Most "Enter Mission" areas have an explorable area that you can only access once you have completed the Enter Mission. Make sure that you explore these as well, as they will often have areas that were inaccessible during the mission, such as with the Tahnakai Temple, or areas that are completely outside of the mission area, such as with Nahpui Quarter. Also do not be content to simply do the mission and leave the exploring for the explorable area, as some missions do not have explorable areas, like Vizunah Square, or have areas that are not accessible within the explorable areas. To be sure you must Explore Everywhere!
5) Hug The Walls!!!
6) When hugging the walls, Walk Slowly! If you run it, you can easily skip over little corners and juts that you would have hit had you walked, and these are usually the places that people miss. You can also accidentally skip over these areas if you are not facing the wall that you are exploring. Facing the wall allows you to get the precise angle you need to ensure you have hit every nook you can. Otherwise you can pass them up even when going slowly. You should also do this by using the keyboard, as mouse walking is extremely inaccurate when hugging walls.
7) You should probably try hugging the walls...
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If you do all of these things, all of the time, you should actually come out with 100% explored once you have completed the game and have accessed all the areas.
However, no one is perfect and it is very easy to miss many of the more difficult spots. In fact most people end up missing the same exact spots. It's rather rare for someone to be close to completing the title and have missed an area that most people get. So if you even loosely followed my seven steps above you should have at least 98+% with your initial exploration of the game, through to the end.
It may not seem like much, but you will find that the last 2% you are missing will be split into so many different tiny spots, that you will often find a bit of fog you hadn't uncovered only to discover that you don't even get .1% for your effort. I've uncovered 4-5 areas like this before I got .1% out of it. Though you are more than likely to need a lot less, that's potentially 100 little spots you could be missing, spread through out the entire map.
So how do you go about finding all of these little spots that will make up your 2%? I'm glad you asked.

Leighwyn is by far the player that has helped the most people on this board reach their 100% title. The following are the methods that he has used to find the last few percentages that he and many others have needed to get their title. This is also the method that requires the least amount of external program assistance.
All we need is a 100% map to compare to (broken down in sections):
1
2
3
4
5
6
7
8
Full Map
Note: The broken down maps are mine and the full one is Leighwyn's, so it's likely that one may have more or less spots uncovered than the other, though they are both at least 103% cleared (Meaning we have cleared more than enough area to get the title).
Open guild wars and enter the game with a character that has completed Factions (Game completion is required for this title). You should then put the game into windowed mode by clicking the middle icon in the top right corner, to the left of the "x." Now press the "U" key in order to open the mini map display. Next, drag the mini-map to the top left corner of your screen, then click on the bottom right corner of the min-map and drag it down and out to expand it, fully covering your entire window with the mini-map. It should look something like this:
Windowed Mode.jpg
Now open the 100% map that you saved from above in "Window's Picture and Fax Viewer" (or whatever program you have that will allow you to zoom in on the photo). If you have Windows XP then it should do this automatically when you simply open the file.
Next, zoom in on the map until the image is roughly (or exactly if possible) the same size as your mini-map. Once they are the same size, you can begin the comparison process. Simply line up your mini-map with the same area on the 100% map, so that they are in the exact same position. They should overlap perfectly. Now when you switch back and forth between them, you should see the exact same area in the exact same place, like this:
Mini-map
100% Map
Tab back and forth between the two while staring at the borders of the area. If you are missing a spot in that area, your eye should notice the slight difference between your mini-map and the 100% map and go straight to it. Take note of the exact area you are missing and then go get it. If you do this with your entire map, you should have no problems finding the last 2% or so that you need to get your title.
Make sure to use the U mini-map and not the full map that you get when you press "M." The full map contains clouds that will obscure your vision and mess with your eyes when trying to pick out color and shape variances. It will also show the outpost emblems which can obscure areas that you need.
Another thing to note is that it is much easier to set up your 100% map to the area you want to examine, and then move your mini-map to line up with it, as you can easily drag the map surface back and forth on the mini-map in order to line things up. Also in case you weren't aware, and many people aren't, you can use your mouse's wheel button to zoom in on your mini-map to have a closer look at specific spots.
This method is far superior to having both maps side by side and simply looking back and forth, as your eyes will not hold the images as readily and you will lose a lot of information in the back and forth movements. If you use Leighwyn's method and rapidly switch out the images, any spots you are missing should jump right out at you.
Here are some additional tips for this method suggested by Leighwyn:
1) Sometimes when comparing maps, the only thing that appears different is the shadowing. A big example of this is the region between the SW and SE corners of Nahpui explorable and mission area, respectively. That little region of empty space has the slightest change in shadowy hue when you fully reveal it. Another example of this rare phenomenon is the western edge of the Jade Brotherhood, docks, headquarters, island, thingamabob, which is clearly seen on a zoomed out map (the wonderful line glitch) but on a zoomed in map, only changes the water ever so slightly.
2) The fast-swapping technique works well on zoomed-out Canthan maps, but only in areas that have external edges and that aren’t in Kurzick territories. This is probably the quickest way to find where there are missing spots on the Island and Jade Sea areas.
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A variation of this method, which I believe is the one that Leighwyn is currently using, is to save pictures of your own map and compare it to the 100% map with an image program. If you have an image program and know how to use it, simply open the 100% map in your program and then open an area of your map as another layer that lines up with the 100% map. Then switch back and forth between the layers. Sometimes putting Guildwars into windowed mode will warp the color a bit, so this method may allow you to pick up things you hadn't noticed in windowed mode. If you don't know how to do this, then stick to the first method.
The image program that Leighwyn suggests is IrfanView, it's free to download here:
http://www.irfanview.com/
Make sure to unclick the google software when installing, unless you want it.
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Dougal Kronik uses another method, which was introduced to the boards by LuXa, to find spots people are missing on the map. This method is very popular with Tyrian cartographers, but less so with Canthan, as the nature of the Canthan map makes this method less effective than it is with Tyria.
In order to use this method you must have an image program with the proper functions and know how to use them. This is a method only for those who understand what I am talking about when reading this. If you don't understand it, then you should use the first and most effective method.
You need one of the following 100% zoomed out maps. Choose the resolution that works best for you:
1024 x 768
1280 x 1024
1600 x 1200
It may take awhile to download, as these are bitmap files, which are needed in order to make the most out of this particular method.
Note: These are my maps using a Tyrian character. The Monastary Overlook/Boardwalk area is not normally available to Non-Canthan characters, however, you do not need this area to get 100%. Though there are events in game that will open this area for foreign characters, one of these being The Dragon Festival.
Since I can't explain the process any better than LuXa has, I will simply link to her explanation of the method. Just use my Canthan Maps above instead of the Tyrian maps that she links to. Here it is:
LuXa's Method
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If you have used this guide and found success with it, please make a post here and let me know about it. Also feel free to post a small screenshot (Don't warp the thread) here of your character with the Grandmaster title, if you used this thread to achieve it. ^_^
If you use what's in this thread to the fullest and still come up short, or if you really can't go through the hassle of earning the title yourself, then please read the next post below this one. Also the third post down is a Q&A post that I will be updating regularly with common questions concerning the Grandmaster Cartographer Title, so check it out if you get stuck.
If you couldn't get the title using the information on this thread, please let me know what else you needed so I can add it here. And of course any other suggestions for changes or additions are more than welcomed.
I would like to dedicate this thread to the people that made it possible and from whom I gathered much information contained within: Leighwyn and Shyft the Pyro, (Most of all), RoadKill97, TCfish, Laibeus Lord, Theos, Dougal Kronik, Zephro, LuXa, and Asrial.