Category: Community Maps
In countries like the United States and Germany, federal agencies keep careful watch on the nation’s rivers, and disseminate their observations to the public. But in developing nations, many of the world’s major rivers remain un-gauged, despite the millions of people whose lives depend on them. The Dartmouth Flood Observatory hopes to help solve this problem with a concept they call “satellite gauging sites,” which makes it possible to monitor the flowrate of rivers using freely available satellite data, without the need to build or maintain expensive infrastructure.
They key to this method is the microwave sensors carried aboard satellites like AMSR, TRMM, and GPM. As the amount of water on the landscape increases, emissions in the microwave spectrum decrease – a clear signal that can be used to track flowrate. Microwaves are unaffected by cloud, but absorbed by liquid water, which means that Flood Observatory scientists can monitor river conditions even when the ground is visibly obscured by weather.
The numerical estimates are much less accurate than ground-based gauging, of course, but still extremely valuable. As a relative estimate of how the flowrate is changing over time, they can be used to track droughts and floods, and to analyze long-term changes in the flow regime.
In order to make them more easily available to the GIS community, Esri has added these satellite gauging sites to the Live Stream Gauge map. When you click on one, it displays an estimate of today’s average flowrate, a description of the status (e.g. low flow, moderate flood, major flood), and a graph showing the time series. There is also a link to the station page, where you can get monthly and annual flow estimates, as well as some information about the calibration and accuracy of that particular site.
This latest update also included new contributions from England’s Environment Agency, the State of Nebraska, the State of Oregon, and the Iowa Flood Center – over 3000 new gauges in total – so if you haven’t checked it out in a while, now is a great time to take another look. For those of you who have been using this map, please let us know your thoughts about it in the comments. Thank you to all our stream gauge contributors!
Last week, we updated the World Imagery basemap with more recent imagery from DigitalGlobe and other members of the GIS user community. This latest update features DigitalGlobe imagery for Argentina, as well as the Caribbean and parts of Central America as shown … Continue reading
Earlier this week we updated our Vector Basemap (beta) tiles with additional community content, newer commercial data, and improved map appearance for parts of the world. This is the ninth Vector Basemap update since our Beta 2 release in mid-May. … Continue reading
The pre-conference (pre-con) workshops at the Esri Developer Summit (DevSummit) in Palm Springs on Sunday, March 5th and Monday, March 6th are the best way to kick off the conference. What better way to ramp yourself up on Esri’s latest … Continue reading
Our user community has provided updates to the World Topographic Map! Contributing to Esri Community Maps is easy! This basemap release includes new Community Map contributions to the World Topographic Map. Areas with new and updated content include the country of Thailand and … Continue reading
We are excited to integrate Spain’s lidar derived elevation from Instituto Geográfico Nacional (IGN) into Esri’s World Elevation services (Terrain and TopoBathy). At 5 meters resolution (cell size), this update brings 6 times more details to Spain and a huge quality improvement over SRTM 1 arc sec … Continue reading
We continue to improve the World Imagery basemap with updates from DigitalGlobe and our GIS user community. This update features new and improved high-resolution imagery for areas covering most of Brazil, Saudi Arabia, and Denmark, parts of New Zealand and … Continue reading
Our User Community has updated Esri’s online basemaps with new and updated content. In fact, they have done it 18 times this year! This basemap release includes new Community Map contributions to the World Topographic Map. Areas with new and updated content … Continue reading
This basemap release includes new Community Map contributions to the World Topographic Map. Areas with new and updated content include several cities, counties and facility sites in the United States and the country of Suriname. Much of this release includes 32 counties … Continue reading
Large-scale content continues to pour into the online basemaps. Over 160 million features added to the Community Maps database so far this year! This basemap release includes new Community Map contributions to the World Topographic and World Imagery Map and updates to the World Street Map. Areas … Continue reading