The norm and simple solutions

Last time I wrote about different ways of calculating distance in a vector space — say, a two-dimensional Euclidean plane like the streets of Portland, Oregon. I showed three ways to reckon the distance, or norm, between two points (i.e. vectors). As a reminder, using the distance between points u and v on the map below this time:$$ \|\mathbf{u} - \mathbf{v}\|_1 = |u_x - v_x| + |u_y - v_y| $$$$ \|\mathbf{u} - \mathbf{v}\|_2 = \sqrt{(u_x - v_x)^2…

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The norm: kings, crows and taxicabs

How far away is the supermarket from your house? There are lots of ways of answering this question:As the crow flies. This is the green line from \(\mathbf{a}\) to \(\mathbf{b}\) on the map below.The 'city block' driving distance. If you live on a grid of streets, all possible routes are the same length — represented by the orange lines on the map below.In time, not distance. This is usually a more useful answer... but not one we're going…

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The norm: kings, crows and taxicabs

How far away is the supermarket from your house? There are lots of ways of answering this question:As the crow flies. This is the green line from \(\mathbf{a}\) to \(\mathbf{b}\) on the map below.The 'city block' driving distance. If you live on a grid of streets, all possible routes are the same length — represented by the orange lines on the map below.In time, not distance. This is usually a more useful answer... but not one we're going…

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Hacking in Houston

Houston 2013Houston 2014Denver 2014Calgary 2015New Orleans 2015Vienna 2016Paris 2017Houston 2017... The eighth geoscience hackathon landed last weekend! We spent last weekend in hot, humid Houston, hacking away with a crowd of geoscience and technology enthusiasts. Thirty-eight hackers joined us on the top-floor coworking space, Station Houston, for fun and games and code. And tacos. Matt kicking things off Discussing projects Discussing projects Discussing projects Discussing projects Discussing projects Discussing projects Discussing projects Discussing projects The…

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Looking ahead to SEG

The SEG Annual Meeting is coming up. Next week sees the festival of geophysics return to the global energy capital, shaken and damp but undefeated after its recent battle with Hurricane Harvey. Even though Agile will not be at the meeting this year, I wanted to point out some highlights of the week.The Annual MeetingThe meeting will be big, as usual: 108 talk sessions, and 50 poster and e-presentation sessions. I have no idea how many…

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Isn’t everything on the internet free?

A couople of weeks ago I wrote about a new publication from Elsevier. The book seems to contain quite a bit of unlicensed copyrighted material, collected without proper permission from public and private groups on LinkedIn, SPE papers, and various websites. I had hoped to have an update for you today, but the company is still "looking into" the matter.The comments on that post, and on Twitter, raised some interesting views. Like most views, these views usually…

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Isn’t everything on the internet free?

A couple of weeks ago I wrote about a new publication from Elsevier. The book seems to contain quite a bit of unlicensed copyrighted material, collected without proper permission from public and private groups on LinkedIn, SPE papers, and various websites. I had hoped to have an update for you today, but the company is still "looking into" the matter.The comments on that post, and on Twitter, raised some interesting views. Like most views, these views usually…

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x lines of Python: Global seismic data

Today we'll look at finding and analysing global seismology data with Python and the wonderful seismology package ObsPy, from Moritz Beyreuther, Lion Krischer, and others originally at the Geophysical Observatory in Munich.We've used ObsPy before to load SEG-Y files into Python, but that's not its core purpose. These tools are typically used by global seismologists and earthquake scientists, but we're going to download and analyse data from three non-earthquakes:A curious landslide and tsunami in Greenland.The…

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90 years of well logs

Today is the 90th anniversary of the first well log. On 5 September 1927, three men from Schlumberger logged the Diefenbach [sic] well 2905 at Dieffenbach-lès-Wœrth in the Pechelbronn heavy oil field in the Alsace region of France. The site of the Diefenbach 2905 well. © Google, according to terms.   The geophysical services company Société de Prospection Électrique (Processes Schlumberger), or PROS, had only formed in July 1926 but already had sixteen employees. Headquartered…

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Attribution is not permission

This morning a friend of mine, Fernando Enrique Ziegler, a pore pressure researcher and practitioner in Houston, let me know about an "interesting" new book from Elsevier: Practical Solutions to Integrated Oil and Gas Reservoir Analysis, by Enwenode Onajite, a geophysicist in Nigeria... And about 350 other people. What's interesting about the book is that the majority of the content was not written by Onajite, but was copy-and-pasted from discussions on LinkedIn. A novel way…

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