i downloaded Arcgis explorer.. then i searched for the place that i want to digitalise. I got an aerial view.. then i am lost..
how do i proceed from then?
i want to digitalise my city and extract the coordinates...:(
ArcGIS Explorer Desktop isn't meant for extensively creating new data, just for viewing existing data layers. If you wish to create your own data, I recommend you to get either an affordable ArcGIS for Home Use licence for ArcGIS for Desktop or, in case you are looking for a free solution, to have a look at Quantum GIS (QGIS):
The ArcGIS for Home Use licence will give you more tools and more advanced possibilities compared to Quantum GIS, and is a tremendous deal for the price and what you get, but QGIS may satisfy your needs and have a lower learning curve.
You need to create a new layer (schapefile) first. But if you have no experience at all using any form of GIS, I really recommend you to start reading some QGIS documentation first. Since QGIS is not an ESRI product, you are also better of asking questions on another dedicated QGIS forum, or a more general GIS forum like http://gis.stackexchange.com/