Here I show you around the garden at my parents house, including some of my own plants that currently live there, including the dahlias and lavenders grown from seed which aren't looking very happy after being exposed to some unusually dry air, a camellia seed that was originally harvested from one of my parents camellia plants which has germinated, chilli seedlings (Chocolate Cherry and Aji Lemon/Yellow Cayenne) - harvested seeds from plants I grew last year, more than one Kea Plum tree, Kiwi fruit, tulips, gooseberry, Chilean Guava (Ugni molinae), an apple tree, a pear tree, Dicksonia antarctica tree fern, and various Camellia.
Showing posts with label cornwall. Show all posts
Showing posts with label cornwall. Show all posts
Saturday, 28 March 2020
Sunday, 1 April 2018
Cornwall council sets aside £10 million for its birthday next year in 2019
Cornwall council has today announced that it has set aside £10 million for its 10th birthday celebrations as a unitary authority on 1st April 2019
Rumours that the children's committee will be bribed so that the monument will be a larger than life statue of Cllr Bert Biscoe on Trafalgar roundabout gesturing towards the bus lane were denied by the Politburo.
Criticised over the cost of the birthday celebration, and being asked where the money is coming from for this, the leader of the council mumbled something incomprehensible and another councillor said we'll use one of the council farms and plant magic money trees on them.
Cllr Loveday Jenkin however pointed out that magic money trees are not frost hardy and require about 10 years before fruiting so will need protection in winter.
Plans include murals on Lys Kernow, a special committee formed of those children born in Cornwall on the same day as the Cornwall Council unitary authority who will design a monument, and a world record largest saffron cake for its birthday cake.
Criticised over the cost of the birthday celebration, and being asked where the money is coming from for this, the leader of the council mumbled something incomprehensible and another councillor said we'll use one of the council farms and plant magic money trees on them.
Cllr Loveday Jenkin however pointed out that magic money trees are not frost hardy and require about 10 years before fruiting so will need protection in winter.
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| concept of the large lettering to be mounted above the entrance to Lys Kernow |
Saturday, 29 April 2017
Some nice clear satellite images of Cornwall with Landsat 8 and Sentinel 2
The launch of Sentinel 2A and 2B as part of the European Space Agency's Copernicus Program, has increased the frequency with which medium resolution satellite imagery in optical and near infrared is available.
Landsat 8 (and 7) are also still operating, which take a given frame every 16 days each.
Landsat 7 unfortunately has a scan line corrector fault that means there are stripes of missing data:
There was a particularly cloud free image of Cornwall on Landsat 8 on 27th March 2017, which I show below, displayed using tuiview.
Sentinel 2 has also captured some good clear images recently in the area, such as this. These are processed in the Sentinel 2 Toolbox within the Sentinel Application Platform, using sen2cor to process to Level 2A (surface reflectance)
Sentinel 2 also took a mostly clear (apart from some high cloud) image on 27th March 2017:
Since the different bands are at different resolutions, when using the Sentinel Application Platform it is necessary to resample the output under the Raster menu, to process it further. This can produce a very large file, so I used the GeoTIFF / BigTIFF option because otherwise it would produce a file larger than a standard GeoTIFF file can be, when the 10m resolution is used. This can then be converted to a .KEA file for a smaller file size with gdal_translate.
The reason the file size is enormous is the output from resampling has 45 bands, because although it outputs only 10 data bands, that is 2, 3, 4, 5, 6,7 ,8 , 8a, 11 and 12, there are also atmosphere optical depth, water vapour, cloud probability, snow probability, and a scene classification, and then bands describing zenith angle, solar angle for every bands. As an uncompressed GeoTIFF this was 22 gigabytes for each tile, but is less than 1GB as a KEA (and I selected only the first 15 bands using rsgislib).
I have also opened them in QGIS and overplotted a map based on OpenStreetMap:
I will blog again about some of these when I have some time to experiment with processing. I have used the Sentinel 2 Toolbox and sen2cor to process the images, but I would also like to try ARCSI for processing from Level 1C to surface reflectance for Sentinel 2.
Landsat 8 (and 7) are also still operating, which take a given frame every 16 days each.
Landsat 7 unfortunately has a scan line corrector fault that means there are stripes of missing data:
There was a particularly cloud free image of Cornwall on Landsat 8 on 27th March 2017, which I show below, displayed using tuiview.
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| On the left is a visible light band combination using bands 2, 3 and 4 which are broadband blue, green and red bands, and on the right I use band 7 (which is known as SWIR2, which stands for short-wave infrared 2, at around 2.2 micrometres wavelength), band 5 (near infrared), and band 4 (red, but shown as blue here). Infrared bands can be a bit confusing, especially if you have been exposed to both terrestrial remote sensing and astronomers terminology. |
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| A somewhat closer view, with Truro at the top-right, showing Falmouth, the Fal estuary, Camborne and Redruth, and Stithians Reservoir in the centre. |
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| This is from 18th April 2017, with a clear view of parts of Cornwall. |
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| The top image uses bands 2, 3 and 4 for the blue, green and red channels respectively, and the bottom uses 2, 8 (842nm) and 12 (2190nm). |
The reason the file size is enormous is the output from resampling has 45 bands, because although it outputs only 10 data bands, that is 2, 3, 4, 5, 6,7 ,8 , 8a, 11 and 12, there are also atmosphere optical depth, water vapour, cloud probability, snow probability, and a scene classification, and then bands describing zenith angle, solar angle for every bands. As an uncompressed GeoTIFF this was 22 gigabytes for each tile, but is less than 1GB as a KEA (and I selected only the first 15 bands using rsgislib).
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| Four Sentinel 2 tiles combined (UUA, UUB, UVA, and UVB) to provide an overview of Cornwall and Devon - with border overplotted in QGIS - visible light |
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| Using Band 12 = red, Band 8 = green and Band 2 = blue. |
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| Sentinel 2 - 18th April 2017 - visible light |
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| Sentinel 2 - 18th April 2017 - Band 12 (2.2 μm), Band 8 (842nm), and Band 2 (blue). |
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| Landsat 8 - 27th March 2017 - Bands 4 3 and 2 (visible light) |
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| Landsat 8 - 27th March 2017 - Bands 7, 5 and 2 |
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| Sentinel 2 - 26th March 2017 - visible light |
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| Sentinel 2 - 26th March 2017 - Bands 12, 8, 2 |
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| Another possible band combination of the 18th April image, which is visible light but with the red and green channels swapped, and blue stretched a bit further to attempt to see the bluebells in the woodland shown from Sentinel2. The location is just to the right of the gridlines crossing at 183000, 41000 |
I will blog again about some of these when I have some time to experiment with processing. I have used the Sentinel 2 Toolbox and sen2cor to process the images, but I would also like to try ARCSI for processing from Level 1C to surface reflectance for Sentinel 2.
Saturday, 1 April 2017
Cornwall to divide from Devon with new reservoirs
The Duke of Cornwall has published plans today, 1st April 2017, Dy' Kalann Ebrel, for a series of dams in the Tamar Valley. This will have a number of benefits:
Although the required compulsory purchase of the land and buildings will be extensive, the Duke points out he does own quite a bit of it already, and has offered to give an (as yet unconfirmed) discount on new properties in the Duchy's housing development to his subjects who are affected by compulsory purchase.
The above table shows the area and volume of the proposed reservoirs.
To store energy from renewable generation, a cubic metre of water can thus be raised 50m from Dowrgonna to Lyn Tredamar, which means it gains 1000*9.8*50 J of potential energy, or 20m from Dowrgonna to Lannstevan.
If the upper two reservoirs were emptied there could be 17.8 million kilowatt hours stored by raising water to Lyn Tredamar, and a further 10.6 million kWh by raising water to Lyn Lannstevan.
Critics of the project have questioned whether this project fits in with Prince Charles' environmental campaigning however the energy storage system will support the development of renewable energy and reduce reliance on fossil fuels.
The cost of the project is unknown, however Prince Charles has assured his subjects, that it will be cheaper than Trident replacement, and less environmentally destructive than a nuclear war.
- The three reservoirs will generate hydroelectric power. They will be linked by a pumped storage system so that they can store energy generated by wind and solar farms in the area when they generate in excess of demand and allow water through the turbines generating electricity when it is needed.
- The project will allow a new not for profit water company Dowr Kernow which will provide competition for South West Water and drive down prices for customers.
- The new reservoirs will better define the border between Cornwall and England, which it is hoped will prevent a cross-border "Devonwall" constituency from being implemented.
Although the required compulsory purchase of the land and buildings will be extensive, the Duke points out he does own quite a bit of it already, and has offered to give an (as yet unconfirmed) discount on new properties in the Duchy's housing development to his subjects who are affected by compulsory purchase.
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| The Cornwall-England border, showing the three proposed new reservoirs along the Tamar Valley |
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| A closer view of the area, with some detail of the proposals. |
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| Lyn Tredamar, the northernmost of the three reservoirs, with a dam near Boyton (Trevoya) giving a water level of 100m. The border will be restored to the 936 treaty border between King Athelstan of England and King Hywel of Cornwall, which will see West Bridgerule restored to Cornwall, and the part of North Tamerton east of the Tamar will revert to Devon. |
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| The central, and largest of the lakes, Lyn Lannstevan, with a dam at Greystone Bridge and a water level of 70m. There will be a need for a new bridge to carry the A30 over the reservoir, which will also carry a cantilevered cycle track, which will connect to minor roads near Broadwoodwidger enabling bypassing of the flooded section of the road through Lifton and Tinhay. |
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| The southernmost lake, Lyn Dowrgonna, with a dam at the location of Gunnislake bridge giving a water level of 50m. The Tamar Valley Area of Outstanding Natural Beauty is shaded in yellow, and the Cornish Mining World Heritage Site in grey. Some of the historic ruined buildings which are part of the World Heritage Site will need to be moved to higher ground. Doing this in a UNESCO World Heritage Site will be controversial, but it is hoped that the planned moving of Stonehenge to make way for the new A303 dual carriageway will set a precedent which will help acceptance of this action. |
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| The more radical proposal of creating a single 100m level reservoir with a dam at Greystone Bridge. This plan is thought to be unrealistic given the likelyhood of legal action from Devon County Council due to the quantity of land and buildings flooded. |
| Reservoir | Total area (km^2) | Average depth (m) | Volume (million m^3) |
| Dowrgonna (50m) | 7.09 | 16.41 | 116.3 |
| Lannstevan (70m) | 16.96 | 11.51 | 195.2 |
| Tredamar (100m) | 14.09 | 9.3 | 131.0 |
| Lannstevan (100m) | 83.06 | 18.5 | 1538.39 |
The above table shows the area and volume of the proposed reservoirs.
To store energy from renewable generation, a cubic metre of water can thus be raised 50m from Dowrgonna to Lyn Tredamar, which means it gains 1000*9.8*50 J of potential energy, or 20m from Dowrgonna to Lannstevan.
If the upper two reservoirs were emptied there could be 17.8 million kilowatt hours stored by raising water to Lyn Tredamar, and a further 10.6 million kWh by raising water to Lyn Lannstevan.
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| There are approximately 1100 properties expected to be below the waterline, which would rise to about 3600 if the 100m water level option was followed for Lyn Lannstevan. However, it was pointed out that this option would lead to the submerging of Prince Charles Close in Launceston, so therefore the Duke doesn't favour this option. |
The cost of the project is unknown, however Prince Charles has assured his subjects, that it will be cheaper than Trident replacement, and less environmentally destructive than a nuclear war.
Sunday, 23 October 2016
Cornwall and Devon, with the ESA Sentinel1B synthetic aperture radar satellite
The European Space Agency operates the pair of Sentinel 1 synthetic aperture radar satellites.
The advantage of radar is that it is not affected by clouds to the same degree that optical remote sensing is, and there is also useful information gained by the polarisation.
As an example, I downloaded a Sentinel 1B product covering Cornwall and Devon which was taken on 7th October 2016, from the Copernicus data hub.
The type of product I used is the Interferometric Wide Swath mode (further detail).
I used the Sentinel Toolbox to perform orthorectification automatically, and visualise as a RGB with VH polarisation in the red channel, VV in the green, and the ratio between the two in the blue.
The stripmap mode of aquisition, which is less commonly used, provides a higher resolutionof 5m x 5m.
Here is an image from 11th December 2014, with the same colour scheme used.
The advantage of radar is that it is not affected by clouds to the same degree that optical remote sensing is, and there is also useful information gained by the polarisation.
As an example, I downloaded a Sentinel 1B product covering Cornwall and Devon which was taken on 7th October 2016, from the Copernicus data hub.
The type of product I used is the Interferometric Wide Swath mode (further detail).
I used the Sentinel Toolbox to perform orthorectification automatically, and visualise as a RGB with VH polarisation in the red channel, VV in the green, and the ratio between the two in the blue.
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| Truro |
Here is an image from 11th December 2014, with the same colour scheme used.
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| Returning to the interferometric wide swath mode, overlaying roads and placenames for context. The colour scaling is slightly different in this image, making the green band less strong. |
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| A portion from a Sentinel 2A image from 30th September 2016, using bands 11, 8 and 4 (1610nm, 842nm, 655nm). |
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| The Level 2A product includes a basic pixel level land cover classification - there are some errors here note some cloud shadow has been classified as water or cloud, and spurious snow/ice around Porthtowan. |
Friday, 5 August 2016
Using QOSM to provide OpenStreetMap basemap in QGIS for my slopelines project
In previous posts I have described how I have used a segmented DEM with RSGISlib, a method originally developed as part of my MSc dissertation on Martian glaciers, for visualising slopes on Earth.
I have been looking at these again, and have produced a few maps with the QOSM plugin, which dynamically loads OpenStreetMap tiles into QGIS.
These maps below were produced with the Thunderforest Outdoors rendering. The slopelines are as previously, red for convex slopes, blue for concave, with thicker lines denoting steeper slopes.
Previous versions of this had used a version of OpenStreetMap that I was preparing myself from the source data within QGIS. Using the basemap tiles I can focus on adapting the visualisation of the slope lines themselves a bit more.
For a while I thought the QGIS bug I found had recurred which meant that the arrows had disappeared. However it was something wrong in my data dependent styling, not sure how it happened. Once fixed, I show the slope direction with arrows, which is only possible up to about 1:10,000 otherwise the rendering struggles:
I have been looking at these again, and have produced a few maps with the QOSM plugin, which dynamically loads OpenStreetMap tiles into QGIS.
These maps below were produced with the Thunderforest Outdoors rendering. The slopelines are as previously, red for convex slopes, blue for concave, with thicker lines denoting steeper slopes.
Previous versions of this had used a version of OpenStreetMap that I was preparing myself from the source data within QGIS. Using the basemap tiles I can focus on adapting the visualisation of the slope lines themselves a bit more.
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| Bodmin Moor |
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| Camborne and Redruth, including Carn Brea and Portreath |
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| Penzance |
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| Truro |
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| A close up of Truro |
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| Indicating the downslope direction with arrows. |
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| Delabole, showing the slate quarry. |
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| St. Ives |
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| Aberystwyth, Wales |
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| Cadair Idris, Wales |
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| A wider view of Cadair Idris, too small a scale to allow plotting the arrows. |
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| Pen y Fan, Brecon Beacons, Wales |
Monday, 6 June 2016
Atmospheric correction of Sentinel 2 images
I recently downloaded the Sentinel Application Platform including the Sentinel 2 Toolbox.
This looks to be a fairly fully featured image processing program, but what I was most interested in doing is the atmospheric correction for the Sentinel2 images I recently downloaded.
The Sentinel 2 'sen2cor' plugin accomplishes this, which wasn't too difficult to install, making use of anaconda to manage the various dependencies. Once I managed to get the environment variables set, and have it find all of the libraries it pretty much just worked.
After this, I tried using my own script for stacking the bands, which came out with a non-georeferenced image. I then noticed I could save the layerstacked image as a GeoTIFF/BigTIFF from within SNAP. A single 'granule' of Sentinel2 resampled to 10m produced a 9GB GeoTIFF, so I converted to KEA with gdal_translate.
This looks to be a fairly fully featured image processing program, but what I was most interested in doing is the atmospheric correction for the Sentinel2 images I recently downloaded.
The Sentinel 2 'sen2cor' plugin accomplishes this, which wasn't too difficult to install, making use of anaconda to manage the various dependencies. Once I managed to get the environment variables set, and have it find all of the libraries it pretty much just worked.
After this, I tried using my own script for stacking the bands, which came out with a non-georeferenced image. I then noticed I could save the layerstacked image as a GeoTIFF/BigTIFF from within SNAP. A single 'granule' of Sentinel2 resampled to 10m produced a 9GB GeoTIFF, so I converted to KEA with gdal_translate.
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| Sentinel 2 image processed to Level2A, with SNAP and sen2cor. Bands B11/B8/B4 |
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| Zooming in on the Truro area. Penryn can be seen at the lower-left. |
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| Using my rsgislib-landexplorer program to juxtapose geotagged ground-level images with Sentinel2 |
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| The same as above, but the non-atmosphere corrected version of the Sentinel2 image. |
Thursday, 2 June 2016
False colour composite of Sentinel 2 - 30.05.16
After using the script in the previous post to create a layerstacked .kea file for each "granule" within the Sentinel 2 images I downloaded, I created a false colour composite mapping band 11 (SWIR 1610nm) to red, band 8 (NIR, broadband centred around 842nm) to green, and band 4 (red 665nm) to blue.
See https://sentinel.esa.int/web/sentinel/user-guides/sentinel-2-msi/resolutions/spatial for a description of the bands available in Sentinel 2.
Here is a mosaic made in Tuiview:
After some issues with opening .kea files in QGIS (due to having reinstalled Ubuntu recently and needing to recompile KEAlib and then finding that due to being compiled against GDAL 2.1 libraries it didn't work in QGIS which was using GDAL 1.11), I sorted this out, and have a QGIS project file showing the image. I also show some placenames from OpenStreetMap, and hill names from www.hill-bagging.co.uk for context.
Some screenshots of QGIS are shown below:
See https://sentinel.esa.int/web/sentinel/user-guides/sentinel-2-msi/resolutions/spatial for a description of the bands available in Sentinel 2.
Here is a mosaic made in Tuiview:
After some issues with opening .kea files in QGIS (due to having reinstalled Ubuntu recently and needing to recompile KEAlib and then finding that due to being compiled against GDAL 2.1 libraries it didn't work in QGIS which was using GDAL 1.11), I sorted this out, and have a QGIS project file showing the image. I also show some placenames from OpenStreetMap, and hill names from www.hill-bagging.co.uk for context.
Some screenshots of QGIS are shown below:
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| Aberystwyth area |
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| Bodmin Moor, Cornwall. Road construction can be seen at the lower left. |
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| Falmouth and surrounding area. |
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| Snowdon |
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| Truro area. |
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| Plymouth, Saltash and Torpoint and the Rame peninsula |
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