[updated comments originally made for v. 1.4] GeoID is the first iPad optimized application to allow routine collection of plane and line orientations combined with making simple stereonet plots. Data can be exported in a variety of formats (CSV, TXT) and by a variety of means (Bluetooth, e-mail, iTunes). Given that the data are georeferenced from the iPads location services (including a scalable Google Satellite view) this could be quite useful. It also does simple failure analysis.
As a geology professor working with undergraduate and graduate students (and other professionals) doing mapping at all levels, GeoID is the first iPad app that might replace routine use of a Brunton or similar compass. Having just begun to use this app, I have yet to closely compare the results from the iPad with independent measurements, however the precision (reproducibility) seems to be within a few degrees when measured on the same plane in multiple places and with multiple orientations of the iPad. (Measuring planes is nominally independent of rotation of the iPad within the plane. Azimuth becomes noisy near horizontal. Linear elements are measured as lines perpendicular to the plane of the device. It would be better if these could be determined say along the long-axis and toward the top of the device. [A modification was made in v 1.5, but still doesnt offer this as the result.])
At this time, I rate the app with 4 stars based on its:
(1) currently unique capabilities for the iPad to collect line and plane orientations,
(2) ease of use including the simple export options,
(3) choice of display types including stereonets and rose diagrams,
(4) ability to acquire multiple data sets (though not to plot them together), and
(5) potential for becoming something quite powerful.
As it stands, GeoID will likely supplement but not displace routine Brunton use, nor is it a substitute for recording information on a map. To become more generally useful, it would benefit from several modifications. Major improvements would include:
(1) allow annotating individual data, rather than just data sets – in v 1.5 this may be possible on an iPhone (I use an iPad),
(2) plotting different data sets jointly on diagrams and maps,
(3) plot orientations in map view (with or without imagery),
(4) link to photos taken with the iPad (as some other iPhone strike/dip apps allow)
Desirable additions would include
(1) cache map images (and/or import georeferenced images)
(2) provide location data as UTM in addition to Lat-Lon
(3) keep and plot GPS tracks
(4) allow KML/KMZ export with appropriate symbols
In the long run, a tool like this would be most useful if it were incorporated into a GIS package.
*** On the downside – and one of the reasons for this extensive set of comments – is the lack of functioning English language support. This is a major problem and nearly rated a downgrade to three starts, as I would like to communicate directly with the programmers.