[OSM-dev] Developers requested to help provide "completeness" tools

Andy Robinson (blackadder-lists) ajrlists at googlemail.com
Mon May 12 11:59:42 BST 2008


Posted to talk and dev

This post really follows on from my consideration of Completeness metrics. A
number of experienced OSMers who have mapped out there areas have either
contacted me directly or posted through the lists about areas of OSM that
are essentially complete, at least as complete as you would expect from a
conventional on-line map or better.

For those of us who are having to move to new areas to map and to help
others who need to know if an area is "complete" there is a need for a
method of communicating completeness. This will be especially important
across Europe and the USA over the next year or two as the majority of the
mapping is completed.

As mappers we rely upon the coding developers to provide the tools to allow
us to do our work. This email is a plea to any developers who are interested
in working on completeness tool(s), one possible method for which is
described below.

We need a logical method of recoding completeness and a method for
annotation about the completeness so that it can be conveyed to others.
There is one method that I think might work very well and that is the method
that was employed by the http://www.useyourpaths.info/interactive.php
project in the UK where you could click on OSGB grid squares and flag that
all the public footpaths on the OS mapping in that area had been walked and
verified. Once a person had verified a square it was marked by giving it a
green semi transparent overlay. Zoom in on the map linked above to see what
I mean.

It would seem relatively straightforward to me to apply a similar approach
to OSM using the Mapnik Zoom 18 tiles as a background and applying a semi
transparent coloured overlay for each tile that is complete and a link to
the username of the person that last verified the time so that others can
get in touch with them. I would envisage that each tile would toggle on or
off (visible or false) and that the change history would be recorded and
available through the API. I would see the display end of things working
similarly to the manner that the namefinder/export or Chris Schmidt's recent
API viewer would work. The later activates from the layers control on the
map view which is the logical place to provide any completeness facility in
my view.

Discussion open.....

Cheers

Andy





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