Saturday, 29 December 2018

Challenger Expedition as a Story Map

The last two blogposts showed how to create correct polar maps in ArcGIS and QGIS: here from publicly posted class notes blogged, and here to create simple climate & vegetation maps in ArcGIS Online (AGOL) from Esri Living Atlas data.

Let's look at now creating complete maps in AGOL from publicly available data, and analyzing it over time to see their historic significance. This post is the backbone of this story map of the HMS Challenger 1873-1876 Expedition:

  1. Google and find HMSChallenger-Station-Data on this fan site or grab it directly on Dropbox - you can see the metadata by clicking About on the web map in the second panel above, or directly here - note there are other sources, but raw location data is often in separate columns: degrees, minutes and seconds, whreas this is in decimal longitude (X) & decimal latitude (Y)
  2. Log into an AGOL account - you can get a free login, and at 500 points you won't exceed the 1,000 point free limit - create a map and add tags and description from Wikipedia
  3. Change the based map to Oceans, which is the latest from Esri's excellent Living Atlas  series that show the ocean bathymetry brilliantly
  4. Click Add Layer from File and select CSV:
    a. save Excel files as CSV file if you downloaded it - in Dropbox file ends with _redux
    b. remove temp. at depth... columns at far right, as they're read as duplicates by AGOL
    c. bulk-replace spaces and "/"  with "_" (underscore) to make file importable by AGOL
  5. d. Split, reorder and merge dd/mm/yyyy dates to mm/dd/yyyy format legible by AGOL 
  6. Fine-tune the map display:
    a. choose Depth_(fathoms) as attribute to show
    b. while Counts and Amounts (size) may work for you,  select the same by (color) to make depths more legible (the default white-to-blue works quite well)
    c. remember to select Done to save changes, and Save the map you just created
This will yield a static map with all Station Data. We can time-enable this map by activating the time (Year) column: this allows to view the ship's progress by month across the oceans. But for that we most host the spreadsheet data on AGOL: follow Publish a CSV File instructions and then:
  1.  In AGOL go to Contents and select the Feature Layer (hosted) you just created 
  2. Under Layers select Time settings and select the drop down  Year 
  3. Save and Open in Map Viewer, styling it the same as above.
Voilà! You have a dynamic map, where you can follow the deep soundings in the dark blues - especially Marianas Trench along the date line, where Challenger Deep was named after this - and shallower ones in light blues - the last two animation points are the Mid Atlantic Ridge, which this expedition is credited with discovering.

A century later, work by Maurice Ewing's team Lamont Daugherty Observatory on global seabed mapping, however, overshadowed this pioneering work: that is the object of the story map above. 

This exercise shows you how to host and style complete datasets in ArcGIS Online... As in previous posts, we trust this will inspire you to craft your own maps... and help your particular areas of interest!    

Tuesday, 27 November 2018

Climate change alert

[Update 2: Euan Mearns factoid-checking counterpoint highlights, if nothing else, the Gordian Knot-edness of it all...
Update 1: thanks fellow Canadian Texpat Katharine Hayhoe for her efforts in this document and the twitter-sphere]

Tuesday, 13 November 2018

Arctic wrap-up as a story-map

Following my previous posts on geo-awareness and transitioning platforms, I repost here this story map that wraps together the story for the Arctic region on Esri platform. You will find at its end a link to the course that cover both poles on Esri and QGIS as complete exercises in polar mapping.

Wednesday, 24 October 2018

GIS education & awareness

There is a patent need to better explain all things geospatial to us as geo professionals as well as to the public addressed here.

Saturday, 8 September 2018

A fond farewell to two old friends

Over seven years after starting to post on and almost five years after posting mega-datasets on GeoCloud2 via AWS, I have to seriously reconsider my investment in web data. I already mentioned my new direction two posts ago, and now stood down my AWS instance - thanks @mhoegh for his help on Mapcentia - and I will let my account lapse next May, five years after it was created (I already rationalised my Esri accounts, hence the two year gap with opener).

Monday, 20 August 2018

Historic climate data revisited - 4 - polar is POpuLAR

[Update: Part 5 will be the last installment as mentioned at the bottom of this blog-post]

Having explored polar maps here, here and here, was it ever a delight to find one of the earliest maps in that same projection! In This Is the World's Largest and Oldest Map, Culture Trip report how David Rumsey recreated a digital copy of a 1587 map from Milan in no less than 60 pieces:

Wednesday, 8 August 2018

Comparative economics England & Wales since the Middle Ages

My latest post of the 7-part series Toward a rational View of Society on my personal Medium channel, follows my previous maps here of medieval & later drainage of the East Anglia Fens.I expanded a little on the economics in the concluding paragraph in this short presentation.

More polar 'map porn'

[I stole the second half of the title from Reddit group of same name.]

From previous blog posts on Arctic polar maps here and here, let me share two more maps found via my favourite Facebook group Remembering the Franklin Expedition.

Thursday, 19 July 2018

Historic climate data revisited - 3 - circum-Arctic update

[Update: Part 4 provides a further update on platforms available to map polar data]

In my previous blog, how many layers can be combined in an arresting polar Arctic view. They show the almost zero overlap of historic and current weather and climatic data. They herald the importance of oceanic climate data going back before 1880, when any weather data get scarce.