Just because you can’t see evapotranspiration doesn’t mean you can’t map it. In fact, the Living Atlas of the World has long contained data about average annual evapotranspiration for the United States. Today that map is being deprecated and replaced … Continue reading
In the weeks following the disappearance of Malaysia Airlines Flight 370 there has been a huge international effort to locate the plane. People keep talking about finding a needle in a haystack; somehow I think the needle is easier to … Continue reading
Creating a map showing a fire perimeter with ArcGIS Online is more straightforward than you might think. The most important layer—the fire location and perimeter—is a publicly shared layer in ArcGIS Online that is generated from a data feed provided … Continue reading
Often we difference two images to see where change has occurred, and usually that’s a pretty decent approach. I came across this paper recently that had a simple, but effective approach for measuring the change in vegetation over a season. … Continue reading
by Alison Wood, Graduate Student, The University of Texas at Austin
As GIS users, we often have to collect data from many sources and compile them into a single map. For just a few sources and a single map, this might be feasible. But what if you have to make a new map with updated data every day? Or every hour? Automation can save you the enormous time it would take to do that by hand, and also help to avoid the errors that can happen in repetitive tasks done by hand. In this blog entry, I’ll describe an example of automating a process to retrieve data, execute file format conversions, and update an online map; I’ll also talk a little bit about some of the tools and strategies I used that will be useful for someone else automating a similar process.
Evapotranspiration (ET), a combination of evaporation and plant transpiration from the Earth’s surface to the atmosphere, is an important and substantial component of the hydrologic cycle, and should not be overlooked. Scientists at the Numerical Terradynamic Simulation Group at The University of Montana are keeping ET in the forefront, making it possible to access actual levels of ET across the globe, using imagery collected by the Moderate Resolution Imaging Spectoradiometer (MODIS) instrument aboard the NASA satellite Terra. Dr. Qiaozhen Mu and Dr. Steve Running created monthly-averaged estimates with 1 km resolution for the entire globe – MOD16 Project – and are the first to provide such a resource.
Lucky for us, researchers at the Center for Research in Water Resources at the University of Texas – Austin have gone one step further, and created a toobox – MODIS Toolbox – that imports the MODIS images directly into ArcGIS, and produces four data products: evapotranspiration, land surface temperature, normalized difference vegetation index (NDVI), and enhanced vegetation index (EVI).
For additional information about the MODIS Toolbox check out the DATA.CRWR BLOG entry Accessing Historical Evapotranspiration Data in ArcGIS.
Special thanks to Daniel Siegel for assisting with this blog entry. Questions for Daniel: email@example.com
We’ve just updated the Explorer California Fire Map. It can be opened from the ArcGIS Explorer Resource Center as described in our previous post. From Explorer, choose File, then Resource Center, then click the California Fires map in the lower right.
The map now includes MODIS burn perimeters as well as the USGS fire perimeters. Both services are updated regularly, and using this map Explorer will refresh both layers every 15 minutes.
As of this morning the Running Springs Fire in the San Bernardino National Forest is still 0% contained. Last night it crept down over the ridge from the town of Running Springs, where many homes were lost, and it was clearly visible from ESRI and throughout Redlands. Here’s a couple of photos that one of our team members took from their home yesterday evening.
Shown below is an updated Explorer map showing the fire perimeters and MODIS hot spots throughout southern California as of last night. We’ll be updating this as we get updated perimeters.
It was almost exactly four years ago when southern California fires reached a magnitude comparable to today’s disaster. Two of the most extensive that year were the Grand Prix and Old Fires in the San Bernardino and Angeles National Forests near Redlands.
Here’s a screenshot showing the 2003 fire perimeters in gray and current fire perimeters in yellow. Active MODIS hot spots are shown in orange. You can see how the current fires threaten to consume areas that were spared in 2003.
It’s all over the news; fires seem to be burning everywhere in Southern California and the air is heavy with smoke. Yesterday you could see it, smell it, and even taste it. Today, the Santa Ana winds which have been fanning the flames seem to be dying down, or at least they seemed to be doing so this morning.
Below is a screenshot showing some of the data which is being published. The MODIS hot spots (red and yellow dots) are from the Forest Service. The background image is also from the MODIS site, and you can see the smoke trails blowing across southern California and out across the Pacific Ocean. The active fire perimeters (orange polygons) and active fire points (green triangles) are from the GeoMAC site.
The image below shows one of the fires closest to Redlands, up in the local mountains near the town of Lake Arrowhead. The red polygon is the burned area, and the yellow outlines show the fire perimeter at various times. The note links to a local TV station broadcasting live and recorded video of the fires there. The fires have spread and are now burning around the town of Running Springs.
The Canyon Fire was one of the first to hit the news. Shown below is the fire perimeter along with a note that links to online photos.
We also found a KMZ created by the California Office of Emergency Services, and here it is shown on top of the topographic map layer from the ArcGIS Explorer Resource Center.