Prague, Czech Republic
Landscape change from 1984 to 2013
Prague, CZ is a large metropolitan city in central Europe and the current capitol of the Czech Republic. The area has been inhabited for thousands of years, officially becoming a city in the 9th century. It is a rather compact city with an extremely rich history. The focus of this project is to attempt to assess large scale expansion contraction of the city from 1984 to 2013.
The Czech Republic fell under the control of the Soviet Union in 1945. This time was an important era of history, where economic conditions between western Europe and eastern Europe were especially divergent. My goal is to investigate possible large scale changes in the city, focusing on the time from 1989 (the "velvet revolution") to the present day. The changes that have occurred on a social and economic level have been dramatic, I wanted to investigate if those changes are also reflected in expansion of private industry or in the collapse of government funded industry.
I used Landsat data from 1984 (the earliest data I could obtain for Prague), 1991 (shortly after the fall of the USSR), and 2013. All data is from mid to late summer: July 1984, August 1991, and July 2013. For all of the following images I windowed, haze corrected, and stretched images 1%. I attempted several methods that could differentiate between vegetation, barren ground, and structures throughout the years.
|Current view of Prague, CZ. Panchromatic image from 2013. For an unlabelled image click here.|
View images of:
A- Wenceslas Square and the National Museum
B- Letenske Gardens which is representative of many of the well maintained parks in the city now.
C- Charles Bridge (located at C) from the south, looking east on Charles Bridge (towards the city center), looking west, and Prague Castle itself.
D- Prague from the castle rampart gardens.
E- Rocky hills along the river, view south from on top a nearby hill (note the towers of Prague castle in the center distance), and forested hillsides that dominate the river course outside the city.
Naturalistic False Color Composites
The following images are false color composites using bands 3, 5, and 7 (4, 6, 7 for the 2013 data). This highlights manmade structures, which was the focus of the project. Purple/white highlights buildings and roads, while various shades of green indicate vegetation. Some fallow or harvested fields appear white in some of the following images.
Prague in 1984:
Notice the airport one the western edge of the city. This will stay constant throughout the images. The center of the city is just south of the bend in the Vltava River. This area is composed almost entirely of stone buildings, and overall has been not changed significantly for centuries.
Prague in 1991:
The city center is unchanged, however there has been an increase in structures in the surrounding countryside, noticably on the western part of the city and some to the south and east.
At a landscape level there are many more barren fields in this image, likely due to a large amount of harvested barley in this image (a major regional crop). The city itself is darker overall, with much more vegetation mixed into the urban environment. I believe this represents more urban tree plantings after the dissolution of Soviet control. Expansion, while it occurred, is difficult to assess here.
The following comparison is useful in some ways, but is still difficult to determine overall expansion/contraction of the city.
I created NDVI images for all years, with the intention of using these to separate agriculture and vegetation from the city. However, I encountered problems differentiating bare ground and buildings, especially evident in 1991.
Land Cover Reclassification
What I was instead able to do was reclass images to create simple categories: man-made structure or non-man-made. For this I used the near infra-red. This appeared to give the best definition between bare ground and man-made structures. Cross referencing with the 357 composite image, I determined a threshold between vegetation and structures, classifying anything below pixel value of 70 as a man-made structure. This allowed me to create the following reclassed images.
The following image is an overall map of changed landcover in Prague from 1984 to 2013. Red=vegetative increase, Black=construction increase, Yellow=no change.
The center (black in the images above) has changed very little, but the main city overall has seen an increase in vegetation. Growth has been focused on the outskirts of the city, especially around the southern and eastern edges. Larger blocks of red or black outside the city indicate changes in agricultural land-use, not urban expansion/contraction.
I concluded that the city expanded overall, with new growth trending a little more towards a sprawling urban area instead of being highly compacted. There was also an increase in vegetative cover through some areas of the city, likely due to planting more urban trees or establishing parks in what may have previously been open lots on steeper slopes, expecially surrounding the river.
Prague Welcome http://www.praguewelcome.cz/en/
Global Research. Review of: The "Iron Curtain": The Crushing of Eastern Europe, Anne Applebaum. Review by Eric Walberg. http://www.globalresearch.ca/the-iron-curtain-the-crushing-of-eastern-europe-1944-1956/5318851
Map images created using Idrisi Selva by Nathan Holoubek.
Photographs taken by Nathan and Kayce Holoubek.