New Base Maps

On 23-Apr-2005, new Base Maps were supplied from OS and implemented as the base layer on the Coventry Walks Maps.

These OS maps are now the eSiteStreet/Street View maps, replacing the Internet Street Mapping data used for the previous three years.  These new maps are similar in format to the previous ones, but differ in some detailed aspects.  In particular:

• They are (obviously!) more up to date
• The license conditions have changed, and new versions must be taken annually.  This costs more over time, but does mean the base will be more up to date.
• The maps are supplied at HALF the previous pixels/km, but this is fully compensated by being using a higher number of colours.  The end result is about the same, but it does mean they can (and are) supplied by download over the internet, avoiding the cost of making the CD-ROM and postage.
• The maps contain many more road names, with virtually every street now named, whereas before many minor streets were not named.  This results in c.6% increase in final file size.
• There are many more small ponds and woods marked, and a lot of building outlines updated.
• The notation of making public buildings and roads have a dark grey border, and private ones without a border has been much more consistently applied.
• Some text objects have been reduced to a smaller font. 

My processing of the maps has included:

• Reducing them to 50% (last time was to 25% - end result the same)
• Performing slight softening (less than last time, but still some needed to give best view at smaller scales, and give best compression)
• Increased contrast by 10%, reduced brightness by 10%. (end result about same as last time, but slightly higher colour saturation which I accepted)
• I have been able to avoid any "dither" being present in block colours on my master maps. (previously some dither was left in the areas of green woodland and brown buildings, which got further exaggerated during compression for publication.)
   
• Removed from my added layers any "base map updates" which are now on the OS map.
• In a few cases I have moved by text objects a little to avoid text objects which have moved on the base map so that conflicts have been created.  There are probably others which need moving, and these I will do as they are identified.
• Checked the end result as being acceptable.

I have adopted a revised Publishing Standards, in particular:

• Files are published as JPEG files as before.  However they have now been compressed at a PaintShop Pro factor of 40 (originally, I used 80 and then during 1994 progressively changed to 60).  This results in files ranging from about 340KB to about 620KB (till 23-Apr-2005 270KB to about 500KB, and originally 200KB to about 425KB) depending on the amount of information present.

I hope you find the end result an improvement on balance, with all the good aspects outweighing any reductions. 

Any comments please let me know.   webmaster@coventry-walks.org.uk.