Sunday, 28 May 2017

Updating Mars 'Top Trumps' webpages

I have previously created a website for Souness Glacier Top Trumps, based on Colin Souness' work on candidate mid-latitude glaciers on Mars, and my MSc thesis on them.

One of the things covered is whether the object has coverage with the High Resolution Imaging Science Experiment on Mars Reconnaisance Orbiter.

The HiRISE team are continually releasing new images as the Mars Reconnaisance Orbiter is still operating.

I have some horribly obsfucated Python code that can match the shapefile coverage of the Souness objects, to coverage footprint shapefiles, after using QGIS to reproject to a common coordinate system.

I have recently updated my Top Trumps webpages to use shapefiles up to 4th May 2017.

However, the Mars Express tiles remain the same, since the data releases of High-Resolution Stereo Camera process to level 4 (including the derived digital terrain model) are available at NASA Planetary Data System only up to orbits up to 12th Feb 2009.

There do appear to be newer ones recently uploaded at the Freie Universit├Ąt Berlin website, although they are not in the same format as the ones I used from NASA PDS and they are not in the European Space Agency Planetary Science Archive or NASA PDS yet.

The website currently says:

Archive status (highest released orbit): f836 (levels 2 & 3, PSA), 6567 (level 4, PSA), d795 (level 4 VICAR, HRSCview)

To incorporate these would require a more comprehensive reanalysis of the data, since some more Souness objects would gain digital terrain model coverage and some would gain improved resolution coverage.

An example Souness object which now has links to additional HiRISE footprints from the University of Arizona HiRISE webpage.
I also fix a bug whereby if HiRISE covered all of the bounding box of the 'context' of a Souness object, the png overlay for the HiRISE coverage would show only transparency, due to the way in which ImageMagick was used to colourise the rasterised shapefile.

The convert command was modified from
convert {i} +level-colors black,yellow {o}
convert {i} +level-colors ,yellow {o}

so that in the input file,  the value 255 is taken only as the white point, not as both black and white which produced a blank image containing only transparency.

e.g. Souness 83

Souness 83, where the bounding box is wholly covered by the footprint of the HiRISE image PSP_010345_2150.

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