Maps that tell a story

Here is a digitally restored 1610 map of Cambridgeshire from Harvard University Library. While a full copy is <a href="https://cottenham-open.maps.arcgis.com/home/item.html?id=0096c6ea57784f7584b39073934664f1" rel="noopener noreferrer" target="_blank">posted here</a>, this is what mattered at the time:

<a href="https://arcg.is/5rOHD" rel="noopener noreferrer" target="_blank">East Anglia Fenlands Coastal Inundation</a> story map details the choice of (Slide 1) sea level rise models and (Slide 2) a simple map showing the areal distribution (follow the slideshow below).

Exploring ArcGIS Online revealed not only that all DEFRA resolutions are available as web services for 2017 and 2019, but also an Elevation rendering of the 1 m. DTM by the associated  Environment Agency: it shows even better the geomorphology discussed above! 

straight ditches drain subsea area (blues)

Slide 9) although rivers flow down- and sea-ward, they erode their valley back from the estuary toward their source at higher elevation - that's why for example topography will "v" (green) inland and uphill as rivers carve back toward source - so as sea level rises it forms incursions along those "v": that can be seen in the poster as the large incursion to the southwest as a future estuary

One thing that lead me to geology as a student, was my love of reading paper topographic maps in France and in Canada, when we worked out the geomorphology (rivers, hills etc.) as well as the infrastructure (roads, farms etc.)... Likewise, we see how much can be gleaned here from this poster, by correlating sea level rise features with geomorphology and infrastructure! Will this encourage you too to revisit maps in all forms: mobile or web and paper as makes sense?

Slide 10) but when they reach the coast and/or flat areas, they lose their speed and capacity to carry eroded sediment, and they start dropping their load in the form of levees: that is what's shown here as the river paradoxically sitting on a yellow bank stretch across the blue subsea area

Slide 7) roads follow highstands, as makes sense to follow drier ground, either via promontories shown in the slide above, or by skirting the inundation areas in the poster; note also in the slide above that villages lie on higher ground too

All model derivations released by <a href="https://blog.zolnai.ca" rel="noopener noreferrer" target="_blank">Andrew Zolnai</a> under <a href="https://creativecommons.org/licenses/by-sa/4.0/" rel="noopener noreferrer" target="_blank">CC BY-SA 4.0</a>

<li>OS Terrain® 50 - GB | Data type: Grid | Supply format: ASCII Grid | Tiles: TF &amp; TL<li>Sea level rise applied by applying 0, 0.5, 2 &amp; 6 m. mask on terrain to simulate SLR scenarios</li><li>Mask in ArcGIS Pro using raster calculator, the combined into single raster &amp; vector layers</li><li>Output poster at 930 x 609 pixels @ 96 dpi (default based on available screen size), 1860 x 1218 @ 192 dpi (twice default resolution), or 3620 x 2436 @ 384 dpi (four times default)</li><li>Poster &amp; leaflet layouts available in story map: Maps that tell a Story [ here ]</li></li>

Cambridgshire : described with the deuision of the hundreds, the townes situation, with the armes of the colleges of that famous vniuersiti and also the armes of all such princes and noblemen as haue heertofore borne the honorable tytles dignities of the Earldome of Cambridge, performed by Iohn Speede and are to be solde in popes head alley by John Sudbury and G. Humbell. It was published by J. Sudbury and G. Humbell in 1610. Scale [ca. 1:109,890].

red, yellow &amp; green (0.5, 2 &amp; 6 m. SLR) over topography (tan &amp; blue above &amp; below current sea level)

Note this is stock 1 m. (mid range from 25 cm. to 2 m. resolution available from <a href="https://environment.data.gov.uk/DefraDataDownload/?Mode=survey" rel="noopener noreferrer" target="_blank">DEFRA</a>) as a web mapping service, which avoids downloading very large and many tiled datasets. [ See Update 3. ]

This poster is available in these layouts:

Cambridge sea level rise & infrastructure: a poster

start

The maps in these layouts can be <a href="https://cottenham-open.maps.arcgis.com/apps/mapviewer/index.html?webmap=c8fb1eae672c4ff7abc8264cad9f1156" rel="noopener noreferrer" target="_blank">seen online</a>. A <a href="https://cottenham-open.maps.arcgis.com/home/item.html?id=843758cd7bfc41daa2bbd4a5b1d26006" rel="noopener noreferrer" target="_blank">map package</a> description states the sources:

Slide 6) adding an infrastructure base map above these layers shows correlations discussed next

These images are available in these layouts:

I <a href="http://bit.ly/map_stuff" rel="noopener noreferrer" target="_blank">presented</a> and <a href="https://www.geospatialfrontier.com/medialibrary/markets-of-mobility-and-other-sneaky-things-john-nelson" rel="noopener noreferrer" target="_blank">attended</a> livestreams, where <a href="https://twitter.com/John_M_Nelson" rel="noopener noreferrer" target="_blank">John Nelson</a> exhorted us to think out of the map:

Slide 4) John Nelson's <a href="https://www.esri.com/arcgis-blog/products/arcgis-pro/mapping/paper-cut-map-style/" rel="noopener noreferrer" target="_blank">Papercut style</a> was originally meant to enhance topographic maps

Don't you love the language above, and the pen-and-ink landscape and buildings in that banner map section?

DEFRA's <a href="https://magic.defra.gov.uk/MagicMap.aspx?chosenLayers=sssiIndex,backdropDIndex,backdropIndex,europeIndex,vmlBWIndex,25kBWIndex,50kBWIndex,250kBWIndex,miniscaleBWIndex,baseIndex&amp;box=543965:259868:568889:271415&amp;useDefaultbackgroundMapping=false" rel="noopener noreferrer" target="_blank">MAGIC Map App</a> records historic features, but in the absence of an API to overlay it, I simply did a montage in the fortuitous gap in DTM coverage: see below the Devil's Dyke or Ditch line up with the DTM feature marked - note the round feature near the arrowhead - just outside the village of Reach know for a Roman jetty, historic documents like <a href="http://suffolkinstitute.pdfsrv.co.uk/customers/Suffolk%20Institute/2014/01/30/Volume%20I%20(1853)_The%20Devils%20Dyke%20Newmarket%20Samuel%20Tymms_167%20to%20176.pdf" rel="noopener noreferrer" target="_blank">here</a> and <a href="http://www.wuffings.co.uk/WuffSites/Dykes/EADykes.htm" rel="noopener noreferrer" target="_blank">here</a> detail the ditch but not on the 650 m. feature apparently... I've asked around about this feature, so stay tuned!

<a href="https://arcg.is/14XWiS" rel="noopener noreferrer" target="_blank">DEFRA</a> high resolution digital terrain model not only correlate well with this, it also shows more features described in this <a href="https://arcg.is/1yamay" rel="noopener noreferrer" target="_blank">swipe story map</a>, annotated below with 300 dpi copy <a href="https://drive.google.com/open?id=1Z7fFWtdOP8TD6FqNDmnuW7xLfo6_vMLZ" rel="noopener noreferrer" target="_blank">available here</a>.

roads &amp; villages on promontories (tan) and avoid lower areas (colours)

It's been said before: like an abstract condenses all the info into a paragraph, a map give all the information needed for a particular task. Let me show you what the encroachment of coastal inundation immediately north of Cambridge UK looks like. Two things really need to be shown:

<li>DEFRA 1m. Digital Terrain Model in A4 landscape 300 dpi (5.26 Mb) <a href="https://drive.google.com/open?id=1Sieq2CSWR9FaAcbAnUTehGb2h9yTnwV2" rel="noopener noreferrer" target="_blank">here</a><li>DEFRA 1m. Digital Surface Model in A4 landscape 300 dpi (7.28 Mb) <a href="https://drive.google.com/open?id=1Lr0lunvPFXzvCtgk56hGD_8-sG_mzjQh" rel="noopener noreferrer" target="_blank">here</a></li><li>above papercut map of all of East Anglia A4 portrait 300 dpi (9.26 Mb) <a href="https://drive.google.com/open?id=1Cye-5Wgy5zlqbhG02z-4u0mMVVctNTyW" rel="noopener noreferrer" target="_blank">here</a></li><li>blue tone papercut map of all of East Anglia A4 portrait 300 dpi (8.98 Mb) <a href="https://drive.google.com/open?id=1Cye-5Wgy5zlqbhG02z-4u0mMVVctNTyW" rel="noopener noreferrer" target="_blank">here</a></li><li>blue tone papercut map of N Cambridge A4 landscape 300 dpi (4.09 Mb) <a href="https://drive.google.com/open?id=1Cye-5Wgy5zlqbhG02z-4u0mMVVctNTyW" rel="noopener noreferrer" target="_blank">here</a></li></li>

Slide 8)&nbsp;look at all the linear drainage ditches peppering the subsea in blue - subsea of course doesn't mean there's sea water there, but water will pool there - drainage ditches (plus pumps and windmills not shown) keep those areas water-free

roads in grey fill / borders and light blue rivers / ditches over the previous map

Addendum: at bottom see how high resolution digital terrain model helps see even more features!

The answer is DEFRA's Digital Surface Models that map not only the terrain but also what's at the surface like buildings and vegetation: that "mound" is in fact the current village of Reach at bottom right, whereas the River Cam levee shows in glorious detail at top left. Lodes and drainage ditches show in the central purple area below sea level.

Slide 3) as a geologist, I'm mesmerised by <a href="http://www.strata-smith.com/map/" rel="noopener noreferrer" target="_blank">William Smith</a>'s original geologic maps: I explored feathered edges but the coastal inundation edges were too convoluted to show cleanly

River Cam weaving atop yellow band and bisecting lowstand

<li>where will the progressive extent of a purported sea level rise be<li>what current infrastructure will it affect and at what time scale</li></li>

Fast forward 410 years, and not only will landscape and buildings differ, but also the story to tell around Cambridgeshire today. For social enterprise <a href="https://arcg.is/09DvrO" rel="noopener noreferrer" target="_blank">Cottenham Open</a> started a year ago, the local impact of climate change was thoroughly reviewed from public data, and sea level rise models mapped according to current knowledge. While digital media allow the full story to be told, the public really wants a map sheet they can examine and touch. On an early map with cardboard backing and mylar overlay roughly showing modelled sea level rise extents, I saw at an event:

You may well ask: how do you tell linear features apart, like rails, ditches and dykes? Dykes are ancient pathways that leave a mark - either levee/ditch pair, or treaded so long nothing grows along the path - but are not typically shown on road maps. You can correlate roads, railroads and ditches either by turning layers off the web map, or by sliding the web app to have a glimpse of the road map below before the image refreshes. But for for ditches a little more digging was called for...

<a href="https://cottenham-open.maps.arcgis.com/apps/mapviewer/index.html?webmap=c8fb1eae672c4ff7abc8264cad9f1156" rel="noopener noreferrer" target="_blank">Flip here</a> through surface &amp; terrain elevation models, or colour &amp; blue tone papercut maps:

Aside from illustrating the progress of the coastal inundation landward, a closer look shows some intriguing correlations with the local <a href="https://en.wikipedia.org/wiki/Geomorphology" rel="noopener noreferrer" target="_blank">geomorphology</a> (numbers follow the slideshow above):

<li>A4 Landscape 96 dpi <a href="https://drive.google.com/open?id=1ljnK0h_lw-Kil-SI2vvXGjo-WgMoTb3R" rel="noopener noreferrer" target="_blank">here</a> (656 Kb) for low resolution leaflets (1:125,000 - ½ in./mi.)<li>A4 Landscape 300 dpi <a href="https://drive.google.com/open?id=1kauPRbM4aF_6vLwPy6ipXpXix5omWSEz" rel="noopener noreferrer" target="_blank">here</a> (4.12 Mb) for high resolution leaflets (1:125,000 - ½ in./mi.)</li><li>A1 Landscape 300 dpi <a href="https://drive.google.com/open?id=1MH5BlK3B5U9BwMxdmnH5KSOJV5YTozb0" rel="noopener noreferrer" target="_blank">here</a> (22.2 Mb) same size sheet as OS Landranger (1:50,000 - 1¼ in./mi.)</li><li>A0 Landscape 300 dpi <a href="https://drive.google.com/open?id=1rzsb5AQ564gyXj05RBG744HbvwDezc9K" rel="noopener noreferrer" target="_blank">here</a> (36.4 Mb) same size sheet as OS Explorer (1:25,000 - 2½ in./mi.)</li></li>

Slide 5) tweeking it shows the southwestward progress of coastal inundation over topography

One little boy just ran his fingers along the map, tracing roads and feeling the flood map Mylar overlay. Another little girl spotted her house on the Ordnance Survey map, found it on high ground… and heaved a huge sigh of relief!