Volcanic Eruption & Flow, Drone footage


Pick colors from an Image


This useful web application allows you to pick colors from an image either by uploading it or by giving its url. This was very useful when writing an article.


How Groundwater Extraction & Replenishing Causes Surface Deformation & Subsidence


Researchers at Caltech made the animations below which show the seasonal deformation and subsidence of Earth’s surface, respectively,  as a result of groundwater extraction and refilling. This occurs when soil and earth layers are compacted and undergo subsidence due to the decrease of upward hydrostatic pressure balancing the weight of the layers.

Surface deformation and subsidence of Earth’s surface is measured using Interferometric Synthetic Aperture Radar (ISAR). ISAR is also used for natural hazard assessment. This includes applications to regions of volcanic, tectonic (e.g. faults and mountains), and construction activities.


source: Caltech


Research Proposal Writing


Research Proposal Writing for Business, Social Sciences and Humanities covers some good material:


Handy Bash Commands


A few commands I use frequently but sometimes forget.

Concatenate mutliple PDF files

pdftk *.pdf cat output out.pdf

Convert a PDF page to an image

convert -density 150 input.pdf -quality 90 output.png

Batch resize images

mogrify -resize 640x480 *.{png|jpeg}

Crop an image

convert input.png -crop 0x4000 output.png

Create a GIF animation from images (10s delay, loop endlessly)

convert -delay 10 -loop 0 *.png animation.gif