MapBox’s TileMill is a pretty amazing cartography studio. It’s easy to use. That’s the killer feature. We host TileMill on the NeCTAR Research Cloud, but you can download and run it on your laptop.
Strengths: full control over the entire map, combine OpenStreetMap data with spreadsheets, shapefiles, whatever. Sophisticated layering, filtering and zoom-sensitive controls make it the tool if you want to produce a web map for use in another application. Rock solid application, great usability, looks pretty.
Weaknesses: no data editing, no geocoding, limited interactivity features, no wizards, no basemaps. Often overkill for a simple “dots on a map” application. Although it can be coerced into producing static maps (papers, posters…) the feature set is limited (no paper metrics like inches, DPI etc).
Costs: TileMill itself is a free, open source download and you can use whatever you produce without royalties. You can optionally host the webmaps you create on mapbox.com for very reasonable, pay-per-viewer rates.
CartoDB complements TileMill in that their strengths and weaknesses are opposite. CartoDB excels at
dropping dots on a map and spinning up a visualisation, with a range of different types to choose from, including an animation.
Strengths: Super quick to get started with “dots on a map”. Select from number of basemaps. Customise the visualisation using CartoCSS, the same language as TileMill. Interactive maps (“click on a dot for more information”) are almost criminally easy. Geocoding built in. A great platform that you can built a powerful set of visualisations and other tools on top of, using the API.
Weaknesses: Poor support for shapes other than dots. No ability to style the basemap itself (using OSM). Generally flakey – weird error messages, glitchy behaviour. Account limits mean that uploading complex datasets gets expensive fast.
Google MapsEngine is a very easy way to get started, although you risk being trapped in Google Land. It can actually be a useful way to create geodata: drop pins on the map, then download the whole lot as a .kml to load into TileMill.
BatchGeo is apparently another easy “throw dots at a map” application that merits further exploration.