Plotting of the Data

The following outlines the various steps from gathering the information, to the plotting of the data and measuring the ice extent:

1. The search for ice reports and compilation of a text document in a chronology of events.
   

2. For each year the geographical coordinates for every ice sighting, differentiating between pack ice and icebergs for each month, were entered into a spreadsheet. Where coordinates were not given but could be calculated through some reference point this was done. Each entry was denoted by a 1 or a 0, which instructs the mapping program to display each sighting as a discrete point or connected to other point by a line.
   

3. A print (.prn) file was exported from each spreadsheet for each month for each type of ice so that for each typical year there were 6 print files: pack ice and icebergs for each of the months January/February (combined), March and April.
   

4. The ice information for each month was plotted on a map showing the Northwestern Atlantic. The software mapping program used was Versamap 140, available over the Internet, in which the background map was replaced by the appropriate area of the CIA map also available on the Internet. Red crosses and lines were used to denote pack ice sightings, traverses and edges, and green triangles to denote iceberg sightings and traverses through groups of icebergs.
   

5. The maps were saved as PCX files, one for each month, i.e. 3 per year.
   

6. The maps were brought in to Paint for editing. Obvious erroneous ice sightings and traverses were eleted and a red boundary line was drawn indicating the approximate ice edge based on the plotted information and any other information given in the sources.
   

7. The edited map was saved as a 16 colour BMP file.
   

8. Within Paint, the Straight of Belle Isle was sealed off and the area contained within the red boundary line was coloured blue. These "blue" maps were saved as a separate file.
   

9. A procedure was created within Matlab in which each "Blue" map could be read and the blue area calculated. This was done for each map for each year, the results being exported as an ASCII file.
   

10. A Web page including tables was created.
    

11. The BMP files were converted into GIF files for access through the tables.
    

12. The text was converted to HTML and entered as descriptive passages to the maps.
    

13. The print files were merged on an annual basis, edited and converted to HTML for easy access as data files.