A blog on Geospatial 'things'

Image CLAHE Sentinel2

Contrast Limited Adaptive Histogram Equalization (CLAHE) with Sentinel 2a

This week I have been thinking about image stretching. I want to start with a quote taken from the concluding remarks of Image Processing and GIS for Remote Sensing. Image Processing can never increase the information provided in the original image data, but the use of appropriate image processing can improve visualisation, comprehension and analysis Read more about Contrast Limited Adaptive Histogram Equalization (CLAHE) with Sentinel 2a[…]

Interactive Image Segmentation part 3 – Automation

This is the 3rd part in a series on interactive image segmentation. In part 1 I looked at how thresholding an image of coins has the potential to help map circular fields in the desert. In part 2 I applied this watershed algorithm to satellite data and created an output shapefile. In part 3 I Read more about Interactive Image Segmentation part 3 – Automation[…]

Interactive Image Segmentation part 2

This is the second part of a blog series on mapping circular fields. In part one I talked about the challenges for mapping in Desert environments and about how thresholding and the Watershed Algorithm can be used to detect coins – this offers a potentially useful way to map circular fields. These are a challenge Read more about Interactive Image Segmentation part 2[…]

Interactive Image Segmentation part 1

A few weeks ago I saw this tweet from UrtheCast We wish you a happy #EarthDay with this stunning #DEIMOS1 view of crop circles in the desert in #SaudiArabia! #PrecisionAg #Geoanalytics — UrtheCast (@UrtheCast) April 22, 2017 It is a stunning image, captured by Deimos 1, of crop circles in Saudi Arabia. I really Read more about Interactive Image Segmentation part 1[…]

Tableau Public and Earth Observation

Tableau Public is a free service that lets anyone publish interactive data visualizations to the web. Visualizations that have been published to Tableau Public (“vizzes”) can be embedded into webpages and blogs, they can be shared via social media or email, and they can be made available for download to other users. Tableau Public is Read more about Tableau Public and Earth Observation[…]

Sat Colours

I’ve been thinking about how colour could be displayed for a Satellite Image. The Earth is beautiful. In some software, in the legend, a Satellite image is displayed as below Image from It does contain some useful information, ie what band is being displayed Red, Green and Blue, but it tells us very little Read more about Sat Colours[…]