Monthly Archives: February 2015
Software used: ENVI 5.1
The ISODATA method for unsupervised classification starts by calculating class means evenly distributed in the data space, then iteratively clusters the remaining pixels using minimum distance techniques. Each iteration recalculates means and reclassifies pixels with respect to the new means. This process continues until the percentage of pixels that change classes during an iteration is less than the change threshold or the maximum number of iterations is reached.
- Start ENVI.
- From the Toolbox, select Classification > Classification Workflow. The File Selection panel appears.
Search and Discover Authoritative Information from Any ArcGIS Open Data Website
ESRI today announced the launch of a new site aimed to help citizens discover organizations sharing open data around the world and provide direct access to thousands of open government datasets. Citizens can search, download, filter, and visualize this data through their web browser or mobile device.
Since July 2014, more than 1,200 organizations from all levels of government, including the National Geospatial-Intelligence Agency (NGA), and the cities of Raleigh, North Carolina; Tampa, Florida; Charlotte, North Carolina; and Muroran, Japan, have used Esri’s ArcGIS Open Data to configure custom open data sites to serve local citizens and businesses. Now the public can search across all these sites to find authoritative data by location and topic.
“We are excited about the large number of organizations currently sharing open data and believe we have a great opportunity to boost global support for open data and open knowledge,” says Andrew Turner, CTO of Esri’s DC R&D Center. “As more of the 380,000 organizations we work with across the globe begin to contribute open data, we will be able to help foster innovation by connecting the millions of datasets created by government agencies and shared through ArcGIS Open Data.”
Any organization can make its data available through ArcGIS Open Data, and people can now discover this data by visiting opendata.arcgis.com.
Learn more about ArcGIS Open Data at esri.com/opendata.
A very detailed tutorial for deriving surface temperature from Landsat data using QGIS and Semi-Automatic Classification Plugin.
Download the tutorial pdf (link)
Congratulations to Prof. Xia Li, who is reported to be the most cited Chinese researcher in Social Science in 2014. The statistical data is based on the Scopus database from Elsevier. Prof. Xia Li is an expert in the field of GIScience, remote sensing, cellular automata, agent-based modelling, and spatial optimization. He has published more than 200 peer-reviewed papers with a total of 6,683 citations in Google Scholar. He is a Chair Professor at School of Geography and Planning of Sun Yat-sen University, the top ten university in China. I was so lucky to be have him as my supervisor when I was pursuing my master degree at Sun Yat-sen University.
Congratulation again to Prof. Xia Li for this big achievement!
The $916.5 million NASA’s Soil Moisture Active Passive (SMAP) mission has been successfully launched on January 31, 2015 from Vandenberg Air Force Base, at 9:20 am Eastern time atop a United Launch Alliance Delta II rocket. SMAP will acquire global soil moisture in every 2-3 days, providing data for weather forecasting, drought monitoring, flood prediction, crop productivity estimation, etc. Immediately after launch, SMAP enters a busy 90-day period called “commissioning.” It is expected that SMAP will start producing data in May 2015.
NASA SMAP webiste (link)
NASA SAMP Launch News (link)
NASA SMAP Launch Video (link)