[mkgmap-dev] Discussion in Talk-DE about Garmin-maps and their consumers

Thu Jul 5 13:43:23 BST 2012

On 5-7-2012 13:39, aighes wrote:
> The main issue is, that many users doesn't find our maps, because they
> are "hidden". There is only the wiki-list, but this list isn't quite
> usable to normal people. The "fear" is only a minor problem.
>
When I type in Google: "Free Garmin maps" I find my website listed first 
and the OSM Garmin/Download wiki page listed in 4th place.

Similarly searching for "OpenStreetMap Garmin map" lists my website 
first and the OSM Garmin/Download wiki page in 5th place.

Similar results are returned using Bing search.

So, I don't really understand why people can't find the maps.

> So there were two ideas how to fix this issue.
>
> 1)
> Have a prominent website (linked e.g. by openstreetmap.de), which
> contains information to all available maps and guide the user to the
> map, he is looking for. User could watch a screenshot an read the main
> explanations to the map and then will be linked to download-website of
> the map or directly to the download.
>
Ofcourse this is a good idea. E.g. The Dutch OSM page has such a link.

> 2)
> Set up a powerful renderserver, who renders several maps OnDemand
> (inclusive caching of course) and deliver several mapstylings to the
> user directly. This service will also be linked e.g. by openstreetmap.de.
>
> So you are offering such a OnDemand-Service. So it would be great to
> have your opinion how powerful such a server has to be and how is your
> user-feedback.
>
The current server is a few generations old dual CPU dualcore Xeon 2.0 
GHz (4 cores total), 8 GB ram, 900 GB cache and 100 Mbit internet 
connection.

The server generates 3 maps simultaneously at a rate up to about 500 
unique maps per 24 hours. It could be more but at this pace the cache is 
usually full within 24 hours and map generation is throttled. Also the 
internet connection is sometimes fully saturated which takes it's toll 
on disk performance (i.e. disk heads are moving as fast as they can 
while the system is starved for data), this slows the generation of maps.

About 1500 unique users download one or more maps per day at a rate of 
around 300GB per day. Caching levels are about 30% I would guess 
(unfortunately I don't have good numbers on that), it helps tremendously.

So if you plan on setting up a similar on-demand system that provides 
more map types to more people then use at least:
- a modern quadcore CPU
- 2 TB fast disk cache
- Good 100 MBit internet
- 8 GB ram
- unlimited bandwidth usage

I also have experience with on-demand rendering using a renderfarm in 
which case the CPU and disk cache per box is less important, but enough 
ram and fast internet connection remain important. Configuring all the 
details and distributing map updates is a pain in the ass though.

Ofcourse there is still room for smarter caching and reducing the 
cache/CPU usage by producing maps more efficiently (i.e. less versions 
of the same map), but it requires a lot of effort to improve significantly.

Regarding user feedback, I get a lot of it. Lots of thank you's 
ofcourse, but there is also a large group of internet users for which 
you can't make things simple enough and well-documented enough for them 
to manage without help. Picture your typical computer-illiterate 
mother-in-law who decides that she needs a free update for her satnav 
using the babysitter on this side of the screen. Or freshly pensioned 
guy who decides he's going to pick up the geocaching hobby but never 
used a pc before. :p

Those WILL contact you and expect to be helped, for free.

So, if you plan on setting up a similar system like I did: plan for a 
lot of your time to perform helpdesk duties answering silly questions, 
figuring out what the h*ll people are trying to tell you and find ways 
around individual firewall/virusscanner/InternetExplorer problems, etc. :)