OBJECTIVE: In this exercise, you are to compare the street network contents of four maps (really databases), for a place that you know well, as represented in several current on-line mapping services:
The primary focus should be to compare the factual contents: Do the maps (databases) agree with each other and with your experience/knowlege? I.e., are the street names, shapes and connectivity the same on all of the maps? Look closely.
Secondarily, you may notice differences in the interfaces, the graphic design of the displays and symbols, the tools provided to aid the user, the kinds of information privided to the user (scale? grid coordinates? latitude and longitude?), etc. that would affect the utility in any given context. They probably reflect intended use of the maps.
http://viewer.nationalmap.gov/viewer/ a web interface to maps from USGS data.
Hints... Overlays. Clear Map. Pan buttons. GIS Toolbox. "Base Map", "Imagery", and "Blank" buttons.
http://www.openstreetmap.org/ offers maps and data based on user contributed information.
Hints... "Zoom and hand drag pan" to select the area. "Export" Tab, select either the Mapnik or the Osmarender Image, and the PNG or JPG format. Note that you have bounding rectangle and scale (as a representative fraction like 1:27500) on screen here. Hit the "Export" button. It should return an image file that you can save or cut and paste from your browser.
http://www.maps.google.com/ offers maps based on Google's database of geographic features.
Hints... "Zoom and hand drag pan" to select the area. "Print" link. Toggle Satelite vs Map vs Terrain etc.
http://maps.yahoo.com/ offers printable maps based apparently on Navteq's data.
Hints... "Zoom and hand drag pan" to select the area. "Print" "send" and "Save" links. Map, Hybrid, Satellite buttons. Meta-map navigation. Latitude and Longitude in the URL.
Google Earth seems to have a different set of street data than does Google Maps. Do they talk with each other?
Hints... GE requires a download and install and may be getting ahead of ourselves but, if you are game or already using it... turn on the "Roads" layer, leave the others off, and see what it shows you. Don't be fooled by waht you can see in the image data, look for their vectors.
In 2012 Apple rolled-out a go-it-alone mapping system (kicking-out Google) and users were disappointed. Since then, Apple changed project managers, bought mapping technology (TomTom, Embark, HopStop, Locationary, etc) and maybe onto something. Those of you with iphones may want to see how it stacks up.
N.B. I suspect that you will find that even such authoritative maps disagree on basic facts, and that you may find this old cartographic aphorism useful: