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Map Source and Format

This page describes:

 

Source of Basic Maps

These maps are based on Ordnance Survey eSiteStreet/Street View .  The electronic data and the internet licence were obtained from:

   eMapSite - details from http://www.emapsite.com/  . 

These maps form a good basis for the footpath maps - key good points from my viewpoint are:

The disadvantages of using these in preference to a street map such as the AA Street by Street or the Geographers A-Z maps are:

News Apr-2008 :

A new update of the base maps has now been supplied and incorporated.  This is the first update since Apr-2005, but at last it has come!  Indeed I'm impressed that this version is now more up to date than the version OS have on their OpenSpace product, and has corrected a number of inaccuracies on the 2005 and earlier versions.  As well as using the new updated base maps, I have used a sharper version so that it is easier to read road names etc. - it does however increase file sizes a bit, which with additional data (e.g. "back-entry" roads to housed and more roads and buildings on new estates) and all now at compression factor of 30 will slow down loading, but with most users now on broadband I feel this is the correct current compromise.

It is recommended that a paper street map is obtained to give detail support in finding names of roads.  All these maps include a grid derived from the UK National grid, and most street maps show this as 500 metre squares lining up in position (but not the same grid letters/numbers) with the maps published on this site.

Sources of Path Information

The path information comes from many sources, including:

Whatever the original source, I have tried to walk the route, and bring the data in line with what is actually on the ground now.  Where this has not been possible yet, I have an intention to walk the route as soon as possible.

 

The Map Grid

The map grid follows the popular notation for street plans of using letters from west to east, and numbers from north to south.  A continuous sequence across all maps (rather than starting again at A1 on each sheet) is used to ease navigation on the "All Maps" page.

The relation of the grid to the National Grid Reference System is illustrated on a small scale map overlayed with excel spreadsheet grid.  This also shows the relationship to the Warwickshire Definitive Map sheets, and to the Coventry boundary.  This is available in:

   

Format of Master Files

Master files are in PaintShop Pro v.7 format.  A multi-layer format is used:

Most paths are drawn 6 pixels wide in order to show clearly on screen or A4 print, but are reduced to 5, 4 or 3 pixels in areas where finer detail is desirable. 

 

Format and Date of Published Files

Files are published as JPEG files.  Each is the same size as the Master file (2250x1500 pixels) and compressed at a factor of 30.  They are saved as mapnn.jpg file names, where nn is the number of the map.  This results in files ranging from about 487KB to about 923KB (was 340KB to about 620KB before Apr-2008) depending on the amount of information present.

The size and compression chosen result in maps of reasonable detail, but keep the file size just about acceptable from the point of view of:

The date at the top of the individual HTML print full map pages is the date printed for your own records, and the date at the bottom is the date the HTML page was last changed.  Sorry if this is confusing!  If you want to see the date a map last changed, try http://www.coventry-walks.org.uk/maps/ and look at date for mapnn.jpg (where nn is map number).  I tried finding a reliable way to get that date automatically displayed on the print full map page, but have failed so far (if anyone knows a method, please let me know).

See "Print Maps" Page for hints on printing.

 

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