Whilst you may not believe me this is the most important map of the lot, because it gives you what you have to start with. This map will give you all your constraints and problem areas to be designed around. This will make you think outside the square on how your can achieve your dream. The more detail you can place on this map the easier it will be to design what you want later and avoid any nasty little complications which arrive unexpectedly later. 

Where to gather the information

Base Map: The lands Department or Central mapping Authority (depending on where you live). These people can supple a wide range of maps of your property all in different scales, and for different purposes e.g., vegetation maps, soil, contour, photographic and land use. It is always worthwhile approaching your local council to see what they have and are willing to supply especially on zoning and planning.

Examples

​The map on the left is my own property and as you can see, or perhaps not see, it has no contours marked on it. This is because, in the area I live in contours are only marked on maps at 5 metre intervals. This does not mean my block is flat and I needed to use other tools to get the contours on my block.
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What is not marked in either of these maps is where any buildings or any infrastructure is placed at the moment.
This is where Google becomes your friend. 
In Google maps you will get an over head shot of reasonably current conditions on your piece of land. 

Note the difference. Yes one is a more metropolitan area and one is defiantly country but you may have to face this problem also.
Because the contours on it are too far apart. It looks as if I have a flat block and that is not true. When you compare it to the second map, the one I use for my PDC you become aware of contour lines and how important they are in the overall scheme of things. Too far apart and you are left with the wrong impression and it means you will manually have to measure your topography, walk your landscape more often to get a better feel for the land under your feet, especially when it comes to placement on a block.

Now you need to combine these two things together so they need to be in the same units of scale. After you have that done then they will very nicely overlay and to do this you need to use either a light box or a window to trace the structures onto you base map. What you will end up with is this.

Your Base Map should end up looking something like this.
Please note: This is a 10 acre property and I have not displayed all the contour lines on this map, but have noted where they are in 5 metre increments to the side of the map. I did this so I could have a more clear vision of what was there at the time I was working on the brief. 
​Also note I have marked in the flow of traffic around the property. Not just motorised but also the way people moved.