Have you read the top Pixalytics blogs of 2016?

Artist's rendition of a satellite - paulfleet/123RF Stock Photo

Artist’s rendition of a satellite – paulfleet/123RF Stock Photo

As this is the final blog of the year we’d like to take a look back over the past fifty-two weeks and see which blog’s captured people’s attention, and conversely which did not!

It turns out that seven of the ten most widely viewed blogs of the last year weren’t even written in 2016. Four were written in 2015, and three were written in 2014! The other obvious trend is the interest in the number of satellites in space, which can be seen by the titles of six of the ten most widely read blogs:

We’ve also found these blogs quoted by a variety of other web pages, and the occasional report. It’s always interesting to see where we’re quoted!

The other most read blogs of the year were:

Whilst only three of 2016’s blogs made our top ten, this is partly understandable as they have less time to attract the interest of readers and Google. However, looking at most read blogs of 2016 shows an interest in the growth of the Earth Observation market, Brexit, different types of data and Playboy!

We’ve now completed three years of weekly blogs, and the views on our website have grown steadily. This year has seen a significant increase in viewed pages, which is something we’re delighted to see.

We like our blog to be of interest to our colleagues in remote sensing and Earth observation, although we also touch on issues of interest to the wide space, and small business, communities.

At Pixalytics we believe strongly in education and training in both science and remote sensing, together with supporting early career scientists. As such we have a number of students and scientists working with us during the year, and we always like them to write a blog. Something they’re not always keen on at the start! This year we’ve had pieces on:

Writing a blog each week can be hard work, as Wednesday mornings always seem to come around very quickly. However, we think this work adds value to our business and makes a small contribution to explaining the industry in which we work.

Thanks for reading this year, and we hope we can catch your interest again next year.

We’d like to wish everyone a Happy New Year, and a very successful 2017!

Identifying Urban Sprawl in Plymouth

Map showing urban sprawl over last 25 years in the areas surrounding Plymouth

Map showing urban sprawl over last 25 years in the areas surrounding Plymouth

Nowadays you can answer a wide range of environmental questions yourself using only open source software and free remote sensing satellite data. You do not need to be a researcher and by acquiring a few skills you can the analysis of complex problems at your fingertips. It is amazing.

I’ve been based at Pixalytics in Plymouth, over the last few months, on an ERAMUS+ placement and decided to use Plymouth to look at one of the most problematic environmental issues for planners: Urban Sprawl. It is well known phenomenon within cities, but it can’t be easily seen from ground level – you need to look at it from space.

The pressure of continued population growth, the need for more living space, commercial and economic developments, means that central urban areas tend to expand into low-density, monofunctional and usually car-dependent communities with a high negative ecological impact on fauna and flora associated with massive loss in natural habitats and agricultural areas. This change in how land is used around cities is known urban sprawl.

As a city Plymouth suffered a lot of destruction in World War Two, and there was a lot of building within the city in the 1950s and 1960s. Therefore, I decided to see if Plymouth has suffered from urban sprawl over the last twenty-five years, using open source software and data. The two questions I want to answer are:

  1. Is Plymouth affected by urban sprawl? and
  2. If it is, what are Plymouth’s urban sprawl trends?

1) Is Plymouth affected by urban sprawl?
To answer this question I used the QGIS software to analysis Landsat data from both 1990 and 2015, together with OpenStreetMap data for natural areas for a 15 kilometre area starting from Plymouth’s City Centre.

I then performed a Landscape Evolution analysis, as described in Chapter 9 of the Practical Handbook of Remote Sensing, written by Samantha and Andrew Lavender from Pixalytics. Firstly, I overlaid natural areas onto the map of Plymouth, then added the built up areas from 2015 shown in red and finally added the 1990 built-up areas in grey.

Detailed map showing the key urban sprawl around Plymouth over last 25 years

Detailed map showing the key urban sprawl around Plymouth over last 25 years

The map, which has an accuracy of 80 – 85%, shows you, no major urban development occurred in the city of Plymouth and its surroundings in the last 25 years – this is of course about to change the development of the new town of Sherford on the outskirts of the city.

However, as you can see in the zoomed in version of the map on the right, there is a noticeable urban development visible in the north west of the city and a second in Saltash in Cornwall on the east of the map. The built up area in the 15km area around Plymouth increased by around 15% over the 25 year period. The next question is what are the trends of this sprawl.

2) What are Plymouth urban sprawl trends?
A large amount of research tries to categorize urban sprawl in various types:

  • Compact growth which infill existing urban developments, also known as smart growth, and mainly occurs in planning permitted areas
  • Linear development along main roads
  • Isolated developments into agricultural or wildlife areas in proximity with major roads.

These last two have a bad reputation and are often associated with negative impacts on environment.

Various driving forces are behind these growth types, creating different patterns for cities worldwide. For example, rapid economic development under a liberal planning policy drives population growth in a city which then is expands and incorporates villages located in near or remote proximity over time. This is fragmented approach, and results in a strong land loss.

But this is not the case for Plymouth which in the last 25 years showed a stable development in the extend permitted by planning policies with a predominant infill and compact expansion, a smart growth approach that other cities could take as an example.

These conclusions can be taken following only a few simple steps- taking advantage of free open source software and free data, without extensive experience or training.
This is a proven example of how you can make your own maps at home without investing too much time and money.

This is the end my internship with Pixalytics, and it has been one of my best experiences.

Blog written by Catalin Cimpianu, ERASMUS+ Placement at Pixalytics.