Tutorial - Creating Maps from Internet Data

I've been asked to provide details on how to create maps in RealMaps using vector data. Here is an example for the Virgin Islands. This whole process took less than 15 minutes on my Revo :-

Step 1 : Go to the Coastline Extractor web site and enter the geographic range of interest. Make sure that the MapGen format is selected and decide whether you want the data zipped or not. It's always a good idea to enable at least a 'Quick Plot' to ensure that you've got the right area.

Step 2 : Press the submit button and after a short pause you are presented with a screen like this :-

Step 3 : Download the data and unzip it if required. Transfer to the Psion if downloaded on another machine. The \Documents\Maps\Overlays directory is ideal.

Step 4 : Run RealMaps and select 'Create' from the file menu. Enter the geographic range. Normally you should leave the Aspect Def set to 'Correct'. Put in an approximate desired display size - note that the created map usually takes far less memory on disk than it does to display. Tap 'OK'

Step 5 : Have a look at the calculated size and use the adjust button if you want to redefine.

I often put in a set scale once I've got an idea, eg. here I've decreased the map size a bit so that it's 1500 pixels/degree.

Step 6 : Tap the 'Create It' button to bring up the save file dialog. Leave the 'Load and Def Ref' option set to 'Yes' so that RealMaps will create the map reference points for you.

Step 7: Select the downloaded coast data in the Overlay (TXT) option. Choose the line width and also the 'File Layout'. Important note : the MapGen format is long-lat NOT the default lat-long layout.

Step 8 : Wait while the coast data is drawn and once completed, use the 'Save Modifications' option from the 'Add' menu. This automatically patches the map so that it can be distributed.

Additional information such as place names can also be obtained and overlaid in the same way. Alternatively, names can be added using the Annotation function alongside a guide or atlas.

You can view the map here or download it in MBM format (17KB). [NB: if you are using my MBM2BMP utility then you will need to right-click the 'download' link and select 'Save Target As']

By the way, I've deliberately broken one of my own rules here to illustrate a FAQ - this map is a very big jump from World2.MBM (8 pixels/degree). There are very few points on World2.MBM that fall inside this bounded area, so if you were actually going to use this map, it would be a good idea to create an intermediate one - otherwise zooming in could be very tricky !.

Last updated 19 February 2000

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