How Do I Build My Own Maps?

We at Adit Limited were very aware of the difficulty that most individuals experience when confronted with the task of building a map. We developed AditMap as a resource for building and maintaining effective maps in a simple and logical manner. AditMap was developed before the wide availability of maps and mapping resources we have today. Maps were (and for many still are) expensive to acquire and can involve the user in the complex issues of copyright and licensing.

AditMap has become popular with a large group of non specialised map users and makers because it helps apply a wide range of freely available resources to the task of mapping, recording, analysing and presenting data. You do not need even a low cost tool such as AditMap to build maps or to apply the techniques described here but such a tool can simplify the task enormously.

No apologies for referring to the capabilities of AditMap frequently in this section but do bear in mind that the techniques and issues raised are of general interest and application as well.

The simplest map that can be created with AditMap is a blank area. All it needs is the entry of a location and a scale. What use is a blank map? Well, it can be used straight away to plot data. There may be no topographical features but the data plot on the blank map might well be all that is required to analyse the relationships between the data. In practice, it is probably necessary to add something else. We might need something to help the user of the map understand the scale of the relationships. It might also be that other key topographical features are also important to understanding the data relationships.

The next simplest map form might be a scanned image or picture – again where the location and scale is understood. This is also where we might get drawn into the difficult area of copyright. Clearly we can use any image such as a hand drawn sketch map or a photograph we have taken ourselves without contravening any one else’s legitimate copyright.

One should check of course, but in all probability it would be legitimate to use a scanned image from a map in your possession provided that you only intended it for personal use. The difficulties arise where you want to share or publish your map. Many web sites make map images freely available for non-commercial use although it would be best to check the “small print” in each case to ensure that you understand what the copyright holder defines as commercial use. Commercial users may have to bite the bullet and investigate the availability of suitable maps on a paid for basis.

The other problem with general purpose map images is that they are probably already stuffed with features and details that are not necessary for your map. To effectively communicate your purpose the best maps have only the features necessary and carry little in the way of extraneous information or detail.

The major problem with all scanned or downloaded images is that they are just that. They are difficult to re-size without losing or distorting detail. It is just about impossible to merge more than one image (unless specifically designed to do so) to produce a single map or to re-scale a map based upon a picture or image. Our ideal computer based map would be constructed using vectors. A mathematical definition of a vector would be “a variable quantity that has a magnitude and direction and can be resolved into components that are functions of the co-ordinates”. Simply put, the information used to construct a map based upon vectors is a description of how to draw the map and not just a picture of the result. Re-scaling a vector map is a simple process – one simply modifies the instructions used to construct the map. Merging instructions from more than one map is again a straightforward process and this can allow the construction of large and detailed maps from small sets of components.

So where do we get the vectors or instructions required to draw our map?

1.They can be purchased from a wide range of sources plus there are some free resources on the Internet

2. They can be constructed from survey information based upon site measurements or even the output from a low cost hand held GPS (Global Positioning System).

3. Allowing for copyright issues they can be derived from other maps or they can be based upon your own sketch maps and photographs. For computer based mapping this can involve the use of graphic tablets, digitisers or automated line tracing facilities such as those provided by AditMap and some “high end” CAD software programs.

It is worth remembering that some image files such as PostScript carry vector information as well as (or instead of) purely pictorial data. Some computer based mapping tools such as AditMap can read some or all of the vector information from a PostScript (or EPS) file and thus directly create a vector map from key elements of the image file.