NearMap PhotoMaps
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Due to the new upcoming OpenStreetMap license change, from June 18 2011 onwards NearMap can no longer be used as a data source to derive data for OSM. See NearMap legalities below. |
NearMap is an Australian aerial imagery and location based media company that (amongst other things) creates high resolution aerial imagery over major Australian cities. You can view their imagery at their web portal, NearMap.com, which was launched to the public on 11th November 2009.
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Legalities
In June 2011, Ben Last of NearMap clarified that the new OpenStreetMap license would not be compatible with the CC-BY-SA style license under which data can be derived from NearMap PhotoMaps.
Use of Nearmap aerial imagery as a source for OpenStreetMap was only permitted by NearMap until 17 June 2011, however it was subsequently revealed that existing derived data would be allowed to stay in the OpenStreetMap database.
This means that any NearMap derived data is considered clean and is not a blocker to accepting the new contributor terms, however no new data may be derived for use in OpenStreetMap.
Coverage
NearMap maintain a coverage document that gives the most up-to-date information about the areas covered, and the frequency with which they are re-flown..
NearMap, as of 13 April 2011 covers approximately 171,855 km2, which is ~2.26% of Australia, which is 7,617,930 km2. Areas of open sea are excluded from the coverage area figures.
Accuracy
Brisbane Metro Area
Morb_au has compared a small selection of Brisbane area vertical NearMap images to the DCDB alignment (in Brisbane City, Stafford and Prince Charles Hospital) and has found them to be in close agreement, typically 1 metre difference. Remarkable! (As to whether either layer is aligned to the GPS traces, this is of course a different matter.)
Adelaide Metro Area
User:Alex Sims has compared the accuracy of the 1 Dec 2009 photos in Adelaide near the city and in this region the accuracy is less than 1 metre difference.
Prior to 16 December 2009, the 29 October 2009 data was misaligned. NearMap says: Some misalignment exists in the Adelaide surveys because of some issues with the GPS data gathered during initial 2 Adelaide surveys due to a hardware fault, and will be corrected within the next month (November - December 2009) when those surveys are reprocessed with the next survey.
Melbourne Metro Area
User:Petdr has compared the accuracy of the photos in Melbourne in the area of Yarra Bend Park near Studley Park boathouse [1]. In this region User:Petdr has many traces of the same paths and so can be confident the average of these traces is where the path is. In this region the accuracy is less than 1 metre difference.
Initial Imagery over Melbourne was misaligned. NearMap said: this misalignment is because of some issues with the GPS data gathered during initial 2 Melbourne surveys due to a hardware fault, and will be corrected within the next month (November - December 2009) when those surveys are reprocessed with the next survey.. Melbourne was reflown on 13th November 2009 with the hardware fault rectified. The new survey was processed along with reprocessing the previous two misaligned surveys (12th October 2009 and 6th November 2009) and all 3 surveys were updated online by 24th November 2009.
