|
Hello Everyone, I'm new in Openstreetmap and I have a work to do with it. I have to to devise a way to assess how good the mapping coverage is in South Africa, just to have an idea of the quality. For example I thought to compare the density of information on a specific area in openstreetmaps with the data of the same area but from other sources. What about this way? Anyone has any suggestion? Thanks.
This question is marked "community wiki".
|
|
There is a detailed study available that does just this. Though the study is from way later than the question... |
|
Hi This is not a value based comparison but you can at least use this tool to get a visual density comparison. Have a look at: http://mc.bbbike.org/mc/ |
|
I don't think the quality is very easy to determine and is going to be highly variable. I have spent significant time mapping certain rural areas which if compared to Google or Bing Maps is significantly better and more accurate in OSM. It depends on what work you are going to be doing. Google has done a large amount of automated mapping so you will see the country littered with lakes where there is unlikely to be lakes or even puddles for longer than 5 days a year every 10 years when it decides to rain. Comparing density in that instance would give you a false comparison. OSM data is mostly from individuals and well vetted imported data, so the data that is available is of fair to high quality in my opinion. For things like the electricity network OSM is by far the best if not the only source of data you will find. The ESKOM (national provider) would likely be better but that is private and out of reach and heavily licensed I suspect should you even be able to get access to it. |
|
Alternative non-OSM data sources: Major city municipalities (Cape Town, eThekwini, etc) generally have fairly good quality "authoritative" data available (on request) which could be used to compare against OpenStreetMap. On a national level, you would likely need to turn to a commercial providers like AfriGIS. Cape Town and Durban (eThekwini) municipalities kindly provided snapshots of their road network to the project. Therefore the coverage is quite good in these cities. Cape Town also benefits from having many OSM mappers. The rate and quality of mapping in rural South Africa has improved since the NGI aerial imagery became available.
permanent link
This answer is marked "community wiki".
|
Thank you for your help. This kind of assessment is not for a specific use, I think it could be also useful comparing the density of the data between two different areas, with the average in South Africa o something similar. Is it possible to do this with OSM?
You'll probably need to start thinking about what you mean by "quality". Is it the road network, POI density, building density (or shape!), or something else? Also if something IS in both OSM and the source(s) that you're comparing with, how do you know what is correct?