Well, it’s Water Wednesday. Today’s Landsat highlight is a time lapse video (2007-2017) showing the effect of a 2010 dam breach on the water level of Lake Delhi located in Delaware County in eastern Iowa. Notice the dramatic decrease in water and the exposure of large sandbars and the refilling of the lake as the dam is restored.
This year we are celebrating 50 years of the Landsat earth observing satellite mission. Landsat data helps us observe changes in our communities and environment over time.
Saturday, July 23, 2022 marked the 50th anniversary of the launch of the USGS/NASA Landsat earth observing satellite mission. With the launch in 1972, Landsat has continued its earth observation mission and become the longest continuous earth observing satellite.
Enjoy this video recalling the launch and explaining the beginning of the earth observing satellite mission, Landsat 9 – Part 1: Getting off The Ground: https://www.youtube.com/watch?v=FlRf17Egexo.
We are continuing our celebration of the 50th year of the US Landsat satellite imagery program. This week we are heading to the lake – Clear Lake, Iowa, located in north central Iowa.
Below are four images showing Summer Solstice (6/13/2019), Fall Equinox (9/17/2019), Winter Solstice (12/22/2019), and Spring Equinox (3/18/2019) from Landsat 8. The images are presented in color infrared which shows vegetation in red rather than green for better contrast.
At Summer Solstice things are still greening up while at Fall Equinox the fields are all green and some are beginning to be harvested.
Observe the different states of the lake: open water, snow covered, and frozen.
The topography of the landscape (ie. hills and roughness) are much more apparent with snow on the ground. In the summer/fall images, it all looks flat.
Welcome to another Throwback Thursday. Today we are going back into the archives to compare imagery from the first five Landsat satellites (all images are featured in natural color). Click on each image for a closer view.
Try to notice the differences in resolution and image quality between the different years.
Another thing to note is the wide seasonal variation between the images. All the images were from the same three week period in April. Some images are have snow while other years are very green.
Observe that the Des Moines River is swollen in the Landsat 4 -1983 image.
Landsat 1 – April 5, 1976
Landsat 2 – April 3, 1975
Landsat 3 – April 21, 1980Landsat 4 – April 15, 1983Landsat 5 – April 12, 1985
You can explore the raw images using this web app: https://arcg.is/0XrG4f. Happy exploring.
This year we are celebrating 50 years of the Landsat earth observing satellite mission. Landsat data helps us observe changes in our communities and environment over time.
Thanks for stopping by and keep observing the world around you!
What changes do you notice in this Landsat time lapse video?
1) The areas of purple and white in the image are urban areas. Throughout the video they fill in the area from the bottom to the center. The pink areas are farm land.
2) Did you notice the increase in the number of retention ponds (dark blue specks in the urban areas) over time? Retention ponds are used to prevent flooding and provide for water storage in urban areas. As areas become urbanized there is often more surface covered in concrete, parking lots and buildings. There are fewer places for the water to flow directly into the ground.
3) Did you spot the golf course on the northern edge of the city?
This year we are celebrating 50 years of the Landsat earth observing satellite mission. Landsat data helps us observe changes in our communities and environment over time.
Over the past few years the ISU GIS Facility has hosted a number of mapathons. Most of our mapathons have a time set aside for mapping in Iowa and then a time where we focus on international projects.
It is amazing what even a small group of mappers can do to add to the OpenStreetMap basemap in a small town in Iowa. Below are three examples of demonstrating how a mapathon event can add to the OpenStreetMap.
As a way to celebrate GIS Day and OpenStreetMap, we are encouraging everyone to go online either during this week or on GIS Day and contribute to the OpenStreetMap basemap. You may consider improving the basemap in your own community. Here are several projects to consider:
Public Lab Mongolia – https://tasks.hotosm.org/projects/9560/ Public Lab Mongolia (PLM), a local non-governmental organization in Mongolia, is leading the Mongolian chapter for volunteer mappers through the HOTmicrogrant COVID-19 project, as part of their mission to promote open data and disaster preparedness. This mapping will also help with COVID-19 response efforts. This project is to map Ulaanbaatar capital city of Mongolia, is organized by PLM in collaboration with the Mongolian Geo-spatial Association and local universities.
Hurricane Eta – Nicaragua – https://tasks.hotosm.org/projects/9765 Hurricane Eta brought wind, rain and storm surge to the coast of Nicaragua. This project is to finish the basemap of Bilwi (Puerto Cabezas) by digitizing buildings from MAXAR imagery. Available to beginners, there may be tricky tasks in this project as some areas have been partially mapped with older imagery and vegetation can often hide parts of structures. Make sure to review the instructions for tips on how to overcome these challenges and provide high quality data.
Today we will be joining Joseph Kerski, a Geographer and GIS education enthusiast, exploring Weird Earth: Exploring the Earth with Interesting, Bizarre, and Odd Imagery. Joseph provides a narrated video on Youtube (primarily targeted at educators) but you can also explore these fascinating places on your own using this ArcGIS Online map. Thank you, Joseph, for taking us to new places and uncover hidden gems on our planet!
