GIS data has been and will be obtained from field survey via GPS and remote sensing(prior to which balloons, pigeons, kites, rockets, and other tools like satellites were used to take pictures).
Photointerpretation: geometrically corrected.terrain effects and tilt,relief displacement.orthophotos
image processing
However, data now is explosively accumulating and expanding, which are now built into various databases. Brief introductions will given for these ones as follows(Note: this will be subject to change once new databases or subject databases are found):
This website from duke university lists very good data sources:
http://guides.library.duke.edu/gisdata
Detailed introduction of data sources are as follows:
1. http://opendata.arcgis.com/
The ArcGIS itself launched a search engine for searching and downloading.
News report: http://www.gislounge.com/esri-launches-site-find-open-data/?utm_source=feedburner&utm_medium=twitter&utm_campaign=Feed%3A+gislounge+%28GIS+Lounge%29
2. http://geodata.grid.unep.ch/
This is from the UN Environmental Program, which is a very good data source for the global with national types.
No comments:
Post a Comment