I would like to build a cartogram map using Web GIS.
I have a basemap and a set of raw data in excel.
I wondered what are the steps to build up a cartogram map using Web GIS?
Note: Originally this Question solicited Answers for both Web GIS and ArcGIS for Desktop. A new Question has been asked focussed on ArcGIS for Desktop (Creating contiguous pixel based cartogram using ArcGIS for Desktop?) and so this one has now been focussed on Web GIS (which itself is still quite broad).