I have been playing around with ArcGIS Online and I’m debating whether or not to implement it permanently on my site. My best guess at this point is that I won’t use it for everything I map, but it seems to have its place. I am using it right now on my new “Trailheads” page on a test basis. So far, I’m liking that it allows me to layer multiple files (I am currently using .kml files) onto a single map. It can even load .gpx files that way, so it might have a use for track display possibly in conjunction with waypoints. It can certainly handle more complex web mapping than Google Maps can.
Here is an example of the map I’m displaying on the Trailheads page.
The way it works, at least with .kml files, is that I host the files on my server. I then login to my ArcGIS Online account and create a new map there. With .kml files, I have to set the symbology of the .kml when I create it. ArcGIS Online does not create .kml files. I used Google Earth to create the ones used here. I used custom symbols on my map, which I had to host on my site, and reference as a custom symbol in Google Earth (to the URL for the relevant symbol). In ArcGIS Online, I told it to load the .kml files on my site and it displays them the way I created them in Google Earth. One advantage of doing it this way is that I can make a change to the .kml file on the server and it will eventually update on the ArcGIS Online end. I cannot define refresh times for .kml files, though, so I have no idea what sort of lag to expect before the map reflects changes to the data. That will be one thing I test. Once I create the map on ArcGIS Online, I have to save it there before I can embed it here. If I delete it from my account there, it will no longer display here.
ArcGIS Online can load certain data directly, also. I haven’t tried that functionality yet, but I do wonder if it will allow me more control over legend items than the .kml format allows. With .kml, there is a line in the file with
tags for each feature on the map. If I display the legend, each icon will show “gibberish” next to the icon. It doesn’t matter if the text is different for each item or not, each feature will get an entry in the legend labeled “gibberish”. On this map, the symbols are pretty self explanatory and I don’t think a legend is necessary. But for a more complex map, this could be a problem with using .kml files.
Feel free to comment on what you think about the ArcGIS Online maps, and possibly also which basemap layers you prefer for the kinds of data I display on my website.