By Kenneth Field, Esri Research Cartographer
Tourist trail maps engage people new to an area and guide them to sights of importance or interest, often using a particular theme. The Esri story maps team recently published a trail map of New York City’s High Line and also a short walking tour around Esri’s Redlands campus. Both examples illustrate the way in which web maps allow you to combine basemaps, route information, point of interest markers and multimedia (e.g. photographs) to tell a rich visual story. Web maps like these can be used either as a virtual tour to give a narrative without actually visiting the area, or as a navigation aid as users follow the trail in reality using a hand-held device. In this blog entry, we’ll look at how you can make a walking trail web map.
The Valletta Historical Trail web map (figure 1) shows how ArcGIS Online can be used to author and publish a useful tourist trail. It provides a window on the rich cultural landscape of Malta’s capital city in The Mediterranean, highlighting points of interest along a short, accessible pre-defined route to either use for pre-trip planning, navigation while on vacation or reminiscing about a place previously visited.
Figure 1. Valletta Historic trail web map (click to launch ArcGIS Online web map)
Data were collected for waypoints and the trail route using a GPS receiver. The GPX trail route collected by the receiver was edited using ArcGIS for Desktop (to correct distortions in the data as a result of GPS receiver error) and then importing to ArcGIS Online as shapefiles.
At each waypoint during data collection, a geotagged photograph (and video for waypoint 11) was collected and uploaded to Flickr. A spreadsheet was created using the GPX waypoint file and additional columns were added for titles, description, cumulative trail time (based on GPS receiver data) and URLs for the location of the related media on Flickr. This included links to smaller thumbnail images to optimize display (see Tips for displaying photos in pop-ups). The spreadsheet was dragged into the ArcGIS Online map as a CSV file. Unique symbols were created based on the style of a Maltese Cross, saved online and then applied to the Points of Interest layer so that each waypoint had a symbol indicating the stop number. This gives a sense of order to the route. Additional graphics were added as editable layers including a trailhead label, a graphic of the flag of Malta and the Maltese Coat of Arms. the latter contain links through to further details on Wikipedia.
Popups are used for each waypoint to identify the location, the total trail time estimated to reach that point of interest and a link to the Flickr content. The route itself is used twice, once as a single line and a second time, classified by value and symbolized using a single hue color ramp to show trail gradients. This gives an indication of how steep certain parts of the trail are. The OpenStreetMap basemap is used with 50% transparency to provide useful contextual information at street level to help people locate and navigate and minimum and maximum visibility ranges have been set so that the operational overlay content is only visible at appropriate scales (Trails at 1:36,112; POIs at 1:10,000; Gradient & graphics at 1:4,514). Additionally, operational layers turn off when the maximum OpenStreetMap basemap scale is reached (1:2,255). See Using scale visibility ranges for symbology in ArcGIS Online web maps for details.
Trail maps are a great way to tell a story of an interesting route. ArcGIS Online provide an easy way of authoring and publishing your web map to share it widely. The Valletta Historic Trail web map is designed to be viewed in ArcGIS Online.
Thanks to my former Kingston University GIS students whose fieldwork forms the basis of this web map.