On december 31st Google ended support for App Inventor platform, deleting appinventorbeta.com from servers: the Center for Mobile Learning at the MIT Media Lab is going to provide this useful service for the future. So, just two days before this deadline, I was finally able of releasing ERTdesign, my first ANDROID app. The question now is: how I’m going to maintain the tool in the next weeks? Probably I have to move to Java programming, hoping it will be painless: last week I had to struggle a little to sign my app with system signature, since a few tools in the JDK1.7.0 environment were not working correctly (I had to reinstall the JDK1.6.0 and everything immediately was ok).
ERTdesign is a tool that estimates the depth of investigation for Electrical Resistivity measurements (VES or 2D ERT quadrupoles). The app also calculates the geometric factor of the quadrupole and provides an estimate of the expected Vmn signal at the receiver.
The following electrode arrays are parsed:
– Gradient Array;
– Generic quadrupole: just define the coordinates of the four A, B, M and N electrodes.
The depth of investigation estimate is performed, first, integrating the analytic sensitivity function – for the given quadrupole – and then by calculating the “median z depth”, so that the area under the sensitivity curve is equal to the 50% of the total area (Edwards, 1977; Baker, 1991).
Of course ERTdesign is a free tool.
Waiting for feedback.
ERTdesign on Android Market
Barker, R.D., 1991. Depth of investigation of collinear symmetrical four-electrode arrays. Geophysics, 54, 1031-1037.
L.S. Edwards, 1977. A modified pseudosection for resistivity and induced-polarization. Geophysics, 42, 1020-1036.