Creating a Mobile Map

[This is the third in a series of three posts (Part 1 and Part 2). You can also download the complete article:  Mobile Mapping]

josh2f

Web maps and mashups offer many ways to organize and display historical information. The ability to tile and share historical maps as rasters is relatively recent and presents unique opportunities for map libraries, archives, and environmental historians. For the purposes of research and teaching, it is also useful to take these documents “into the field” through the use of mobile mapping. This allows more vivid presentation of environmental changes, more accurate location of mapped features, and the ability to record observations, GPS points, routes, geotagged photos, and so on. High-level GPS devices have provided some forms of mobile mapping for over a decade now, but it’s suffice to say that these weren’t designed for academics with historical interests and small research allowances. The devices are expensive and they are usually designed to incorporate the most up-to-date GIS data – not historical maps.

Smartphone technology now allows easier and more affordable mobile mapping through apps like ArcGIS, iGIS, and “PDF Maps.” These apps offer a variety of tools that environmental historians can use in the field. Government agencies like Natural Resources Canada (Mirage) and the United States Geological Survey have released some of their historical topographical maps as GeoPDF files, or Adobe files with real world coordinates. Apps like “PDF Maps” can navigate around these files much like Google Maps does, and the phone’s GPS will show where the user is located in the map. GeoPDFs are easy to use, and they are easily shared through email, websites, GIS software, and to virtually anyone with access to a computer. The downside to using these files is that the mobile map is limited to the margins of the PDF and the app will not overlay the documents on top of other GIS features. ESRI’s ArcGIS app allows the device to interact with other layers and add GIS data provided by other ArcGIS.com users. However, as I mentioned earlier, ArcGIS.com does not do well with multiple rasters, and since historical maps are almost always rasters, it is difficult to overlay one historical map over another.

Josh showing how this intersection of environmental, transportation, and cultural signifance appeared on historical maps, Grand-Pré National Historic Site

Josh showing how this intersection of environmental, transportation, and cultural signifance appeared on historical maps, Grand-Pré National Historic Site

We used some form of mobile technology at each of the GeoWATCH events, although the best mobile mapping applications we found for historians (iGIS) only became available toward the end of the project. Participants at each event took plenty of photographs and geotagged them either automatically with GPS, by enabling their phone’s location services, or afterward on Picasa Web Albums and Flikr. In the St. Andrews workshop we had an iPad 2 tablet for displaying the historical web maps from Service NB and ArcGIS.com, and several participants with iOS or Windows phones also installed the ESRI app for this purpose. At the Charlottetown and Grand Pre workshops in October, 2011, we used smartphones, and at this point the “iGIS” app enabled us to customize the maps and show a variety of historical and current GIS layers.

Using mobile mapping, historians can display and explore historical maps, query and measure GIS data just as they would on a desktop, and input place-specific information using GPS. We used the “iGIS” app at the Grand Pre salt marsh and interpretive centre to compare what we were seeing in the natural environment with a Google basemap and historical forest inventory overlays. Nova Scotia produced one of the country’s first forest inventories in 1912, and it has since been digitized and made available for download as GIS-ready files on the GeoNOVA website. Another, much more detailed, inventory offers a recent “historical” perspective on land use change, because it was based on the province’s first aerial photo interpretation, beginning in 1985. By adding these two layers to the Google basemap on iGIS, we were able to locate ourselves in the historical landscape and compare mapped and real world observations with what we knew from other histories and historical maps of the region. The Pre was a highly manipulated landscape. From the dyked harbours of Wolfville and the eroding Boot Island to the rural “town plat” of Horton Landing and the site of the Acadian deportation we were able to walk through these historical landscapes and trace the changes on paper and mobile maps.

iGIS showing the Grand Pre, GPS points of interest in yellow, and Boot Island cover types in green

iGIS showing the Grand Pre, GPS points of interest in yellow, and Boot Island cover types in green

Back on Prince Edward Island, we used smartphones to display the tiled maps of Malpeque Bay and Newton Cross as overlays on the Google basemap. The iGIS app can read tiled rasters and overlay them on Google maps directly on an iPhone or other iOS device. It requires the same processes as the other web maps, scanning the image, georeferencing it in GIS, and then tiling it with MapTiler. To bring the map into iGIS, you simply zip the group of files (see Figure 12) and copy the archived file to iGIS using iTunes. The app unzips the files, asks you what coordinate reference system you used to make it (in the georeferencing stage) and allows you to add the map as a new layer. Using the project properties and “layers” buttons you can make the map visible and adjust the transparency. In the Malpeque salt marsh my class was able to compare the 1845 Bayfield map with the 1944 NTS map in the exact location we were standing. As we learned about the different zones of a salt marsh, and the type of grasses used as marsh hay, we were able to identify where those important agricultural resources would have been located in the nineteenth century. Using the detailed topographical markings on the Bayfield map we were also able to identify where the coastline was situated in 1845 and where the height of land marked the edge of the marsh and the beginning of the agricultural uplands.

Malpeque 1845 overlay close-up of salt mash close-up showing 1845 and 1944 overlays

Malpeque 1845 overlay close-up of salt mash close-up showing 1845 and 1944 overlays

We also used mobile mapping in a field trip to the Acadian forest to help illustrate and explore the widespread phenomenon of farm abandonment and forest regrowth in Prince Edward Island and other parts of the Atlantic region in the early twentieth century. It was not immediately obvious from standing on privately owned woodlot in Newtown Cross, that this scrubby woodlot had once been a farm. The iGIS app helped us identify several historically significant features in the landscape. For one, the 1944 NTS map overlay showed the historical forest outline and the location of a barn and house that had long since disappeared from the property. We studied the map while standing in a clearing with a large mound that looked suspiciously like the ruins of a house foundation. The GPS beacon identified that we were actually in an old field that had long since grown up in forest and had been harvested. The mound was the remnants of a brush pile, and the house and barn were actually located to the north of this location in what is now a stand of spruce. The land which had been cleared in the 1930s was likely already abandoned for agricultural purposes, the house and barns beginning the process of decay.

iGIS app displaying location at the edge of an Acadian forest, Newtown Cross, PEI

iGIS app displaying location at the edge of an Acadian forest, Newtown Cross, PEI

josh2e

The iGIS app also helped identify features in the natural environment that stem from human activity on private land. In recent decades the Newtown Cross property has belonged to absentee owners who participate in a woodlot management plan, and Brian Brown of the Provincial Department of Forestry, took us further into the woodlot to show the results of various management practices. Property boundaries may seem like arbitrary lines on a cadastral map showing land ownership, but exploring nature on the ground shows the dramatic effect a property line can have. As we walked away from the first property toward a steam in the woods we crossed into other properties and saw how the forest had responed differently to managed thinning and planting, selective harvesting, and clear cuts for firewood and lumber. We noticed how the health of the stream bed increased with distance from cleared land and steep slopes, and we saw evidence of changing hydrology and siltation between the 1944 map and today. The historical maps were useful for identifying the early alignment of farms, the location of homestead buildings, the amount of cleared land, and the way the forest was divided between multiple properties. The “back woodlot” was valued and managed differently by the owners whose properties converged in the part of the Newtown River watershed.

josh2f

1944 NTS map of Newtown Cross overlaid on 2010 aerial photos; b) add property lines; c) add hydrology

Mobile mapping brings historical documents to the field, but it also allows students to make and share observations on the documents. This can be valuable for historians who want to create a map of environmental features and phenomena by taking GPS readings in the field. Most GPS devices and some smartphone apps will allow the creation of points, lines, or polygons, either mapped on site or afterward by memory. The iGIS app, for instance, let me identify points of interest on the Grand Pre, Malpqeue, and Newtown Cross field trips, which I could later use as material for writing summaries or displaying the route we took on a descriptive map. Some environmental historians may also want to enter the new features into a GIS for recreating and analyzing aspects of the built environment which have disappeared, for example the outline of a dock based on the location of posts.

Another important way of recording observations on these field trips was through photography, and GPS enabled smartphones are particularly useful (if not the best quality cameras). The use of GPS for geotagging fieldtrip photos was already mentioned; by sharing a geotagged photo or web album, historians are essentially sharing a map of documents with real world coordinates. Each coordinate indicates where the researcher was located when making that particular observation of nature. However, it is also possible to “pin” historical photos to a map and share them in the same way. Google Earth, ArcGIS Explorer, Panoramio, Flikr, and Picasa Web Albums all have this capacity, but another useful mashup, HistoryPin, exists specifically for organizing and sharing historical photos from the global community.

In summary, locative media are changing the way we research and understand history and the environment. Historical GIS opens up a new range of possibilities for teachers and students using maps for environmental history, and mobile mapping is making it easier to take those maps out of the archives. Any historian can create a basic web map or use mobile mapping in a field trip. All that is required are historical maps, a computer with GIS to georeference the maps, and a mobile phone that supports apps. Open source software for each of these stages is freely available, Quantum GIS, MapTiler, and iGIS were some of the examples discussed here, and this article attempts to explain how these applications can be used to use web maps and mobile maps creatively in a learning environment.

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I am an Assistant Professor of Environmental Humanities in the School of Historical, Philosophical, and Religious Studies and the School of Sustainability at Arizona State University. As co-investigator on the Sustainable Farm Systems Project (based at the University of Saskatchewan) I am building on the work of the Great Plains Population and Environment Project, conducting new research in agriculture on the Plains and my own case study of Prince Edward Island. From 2010-2014 I was a SSHRC postdoctoral fellow and then NiCHE project coordinator.