[Gfoss] Critiche ai dati di OSM

Maurizio Napolitano napo a fbk.eu
Gio 19 Gen 2012 19:58:53 CET

Il post è di dopo natale e quindi forse è già passato in lista

Why OpenStreetMap fails to replace official or proprietary base maps in 
a sustainable way ?
     Because it’s not possible to make a map for all zoom levels
     Because the finances are not secured on long term
     Because the data model is not defined
     Because the precision is heterogeneous
     Because the reliability is heterogeneous
     Because the completeness is heterogeneous
     Because it requires attribution
     Because the data are difficult to extract
     Because noone takes the responsibility about the data
     Because it lacks a QA step by an accountable body
     Because it is not multilingual
     Because first acquisition is fun and data update is boring
     Because Google Map Maker Workflow is for the broad public and 
OpenStreetMap workflow for the map enthusiasts

solo oggi però mi sono accorto di un secondo e più dettagliato

[... taglio alcuni pezzi ...]

- Point #1: Cartographers have demonstrated that automatic 
generalization is, at least for now, not possible. If we take the 
example of the UK Ordnance Survey, Vector Maps are delivered with two 
scale ranges: local and district.  Google Maps use various sources of 
data depending of the scales: GeoBasis DE/DKG, TeleAtlas, Europa 
Technologies or their own data.
- Point #3: OSM has always a duality between cartography and GIS. The 
main goal of OSM is to make a map, but GIS data are used to create this 
map. From a GIS perspective, the fact that "You can assign tags ("keys" 
and "values") to any point (node), street (way), area (closed ways) or 
relations (containers of the previous ones). see" creates difficulty 
when you want to use the data.
- I'm really suprised that points #4, #5 and #6 can be questionned. 
These are simply facts. A standard GPS is able to measure with a 
precision of 2 to 5 meters. The digititalization over an orthophoto with 
a 20 cm resolution is able to measure with a precision of 20 to 50 cm. A 
professional GPS is able to measure with a precision of 2 to 5 cm.
- Point #8: this is due to two reasons: all is based on three primitives 
and tags can be associated with everything.
- Point #11: all is in english in OSM. A translation mechanismus should 
exist is order to be able to obtain localized data.
- Point #13: this is the KISS principle. Currently, it's not very simple 
(or user friendly) to acquire data for OSM.

.... cosa dicono gli iscritti di questa ML?


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