Author: Ibrahim El Merehbi

Remove Exif data from Images in Linux, How to

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Images usually contain metadata referred to as exif data. Nowadays this includes your camera or phone name and model. Also the location where the image was taken is also included if the GPS is enabled and you did not turn off geo-tagging.

Here’s how such exif data looks like (excluding location which I have disabled):

exiftool IMG_20171010_223446.jpg

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Borehole NMR – an MRI for Earth’s subsurface

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source: Borehole Nuclear Magnetic Resonance (NMR): a valuable tool for environmental site management, doi:10.5066/F73J3BW0, USGS

Global SRTM Map

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global_srtm_bathymetry_map

The following is an 20x downsampled global Shuttle Radar Topography Mission (SRTM)  map made with Python and Basemap.

Full resolution can be found on wikimedia.

One can notice the depth of the ocean floor, on a global scale, ranges between -2000 and -6000 meters. In some regions though like the Pacific exceed this range and reach 11 kilometers below the sea surface. One such region is the deepest point on Earth, the Mariana trench as shown below followed by a map for a perspective of its location.

368px-marianatrenchmap

Location of the Mariana trench. Wikimedia commons.

Credits: The SRTM dataset used was provided by IFREMER.

Python wrappers for the Generic Mapping Tools on the way

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An interface for interoperability between the Generic Mapping Tools (GMT), a tool used by geophysicists to create research-quality figures, and Matlab has recently been developed that allows GMT users to interact with Matlab and Matlab users to make use of GMT.

GMT wrappers are currently also being developed for the Python programming language, particularly to be used in the IPython/Jupyter notebook due to an initiative by Leonardo Uieda (and his professor Paul Wessel) whose Postdoc is being funded by the NSF. You can watch his talk at the SciPy 2017 conference below.

Some of the mentioned advantages to which I attest  include:

  • Begin and End statements are introduced to eliminate the need to pipe postscript results into a file in each line of code being written. This also eliminates the need to use the -K and -O flags which keep the file open and updates it, respectively. The -K and -O flags are a major confusion for newcomers to GMT.
  • temporary files are created under the /tmp directory, in Linux, so they will automatically be cleaned once the jupyter notebook is closed or the operating system is rebooted. Moreover, every project will have its own  directory so files from different projects don’t get mixed up.
  • GMT documentation straight in the Jupyter notebook
  • Matplotlib- & Basemap-like behaviour, particularly inline viewing of figures, using gmt.show()
  • Pythonic aliases make the compact GMT flags

To contribute: github.com/GenericMappingTools

Reference

Cook, T. (2017), A powerful new tool for research, Eos, 98, https://doi.org/10.1029/2017EO077489. Published on 17 July 2017.

Converting Greenhouse Gases to Rocks

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One of the ways scientists are attempting to reduce greenhouse gases is to inject these gases into the ground. Specifically, they are testing injecting them, into basalt which is type of igneous rocks usually forming the first (rock) layer (sandwiched between the sedimentary & gabbro layers) in the oceanic crust basalt and in volcanic regions.

The above video features Iceland and its geothermal plants. Iceland is a heaven for geothermal energy as it lies along the Mid-Atlantic Ridge (MAR) (i.e. where Mid-Atlantic ocean floor is spreading apart in opposite directions forming a ridge). Most notably Iceland lies along the V-Shaped Reykjavik ridge (figure below; Google maps) which is part of the Norther MAR.

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