A review of the new Landsat Look Data Portal

Awhile back, we reviewed the Landsat Look data portal. I then wrote an update to the original post stating that I did not recommend using it any longer. But, given the rapidly evolving nature of GIS, imagery, and data, good news! – the Landsat Look data portal (https://landsatlook.usgs.gov/) has been revised, warranting a new review.

LandsatLook 2.0 is a tool that allows rapid online viewing and access to the USGS Landsat Collection 2 data. LandsatLook 2.0 leverages resources available via a commercial cloud environment including Cloud Optimized GeoTIFF (COG) and Spatio Temporal Asset Catalog (STAC) metadata. LandsatLook 2.0 replaces the legacy LandsatLook viewer (now known as LandLook, which I reviewed above), which provides access to Landsat Collection 1 scene-based images. The Sentinel2Look Viewer remains available for access to Sentinel-2 images in the USGS archive.

LandsatLook 2.0 allows you to do many useful things, including filtering scenes by querying the Landsat archive by area of interest, sensor, acquisition date or cloud cover, visualizing dynamic mosaics in user-defined three-band composites or in select spectral indicesFilter out cloud contaminated pixels, exporting an image mosaic in a Portable Network Graphics (PNG) format, viewing metadata of source scenesDownload individual band files of source scenes, and searching by address or placename, or panning/zooming to a point on the base mapZoom to a location using the locator functionality from a web browser. You can also overlay the Landsat Collection 2 (C2) Worldwide Reference System 2 (WRS-2) grids on the base map for added spatial awareness, and generate and download a video animation mosaic time-lapse showing how the dynamic mosaic changes over time (which I recommend is a wonderful tool for showing change-over-time in your courses or for your research project).

In my opinion this site sits midway between one that does not require you to watch or read any tutorials and one that requires extensive training. With a fairly quick review of the videos and help documentation, including this video narrated by “cloudguy“, I was able to get up to speed with using the site. Yes, you do need to be signed in to your USGS Eros Data Center registration to download the imagery. I have registered for this account numerous times over the past 20 years but for some reason had to register again to access my account, but once done, I could filter on band, cloud cover, and date, substitute pixels from one scene to another, and download the areas and bands and sensor data that I was seeking. I could not find a way to stream the data into a web GIS, but overall I was pleased to see this resource, found that it is user friendly, and I salute all those at USGS who were involved in making this a success.

Landsat Look – updated data portal – view.

Downloading the data.

I encourage you to give this resource a try!

–Joseph Kerski

The NSGIC Geospatial Maturity Assessment

The National States Geographic Information Council (NSGIC) has published its latest geospatial maturity assessment. Because this Spatial Reserves book and blog frequently reviews regional, state, and other data portals, the NSGIC report fits well into the themes of this blog, providing a summary of geospatial initiatives, capabilities, and issues within and across state governments in the USA.

This information is intended to assist state governments with setting goals, identifying peer states for collaboration, identifying areas requiring attention, and connecting with opportunities and resources. Completing the GMA also offers state governments a chance to reflect on their geospatial strategy, operations, and progress. The assessment is performed every two years. The current assessment results were obtained in the second half of 2021. In the above link, participating states’ report cards can be found, and the full report contains information on methodology, grading schemes, and national trends.

I found this dashboard that the report contained to be particularly interesting and useful. No report like this, especially in the rapidly changing world of GIS and data, can be truly complete, but I salute the authors and others involved with this noble effort. Most importantly I hope this report encourages state and other governments to be as proactive as possible in serving their data in useful ways and across useful themes for the betterment of decision making in society.

NSGIC dashboard.

–Joseph Kerski

Historical Aerials and Maps in ArcGIS Online: Iowa Case Study

ArcGIS Online has emerged as a robust depository for serving and accessing spatial data. Some of its data can be found from the many ArcGIS Hub sites that have appeared over the past few years, while other data is served through custom portals, and some is best found by going directly to www.arcgis.com and searching there. But what about the growing need for georeferenced, online historical maps and imagery as services?

One of the best examples of historical maps and imagery as services is the data from the Iowa Geographic Map Server, served from the Iowa State University GIS facility.  The data set, searchable on ArcGIS Online via the keywords “Iowa Geographic“, is one of the finest examples of the holdings of a state data depository in an easy-to-use format. And rest assured that current maps and images are in there, too!

The data available includes aerial photographs from the 1930s, 1950s, and then every decade from the 1970s onwards.  Also included are additional fantastic sources: An atlas from 1875, a general land office survey from the 1800s, a hillshade from Lidar data, the public land survey system, civil townships, watershed boundaries, and so much more.  Changes in agricultural practice, urban forms and size, river meanders, and much more can be explored via this map.  See the changes for example in Council Bluffs, Iowa, below, from a modern-day bridge and street overlay on top of the 1950s aerial imagery:

Council Bluffs, Iowa. 1950s aerial photography with modern-day transportation infrastructure on top.

In addition, one can add the individual layers to one’s own map by pointing to the server URL found in the metadata for each layer.  That the metadata are well populated is another reason that this data portal has long been one of my favorites.  If one needs to download the data, those data sets are still available via the data portal at Iowa State University on http://ortho.gis.iastate.edu/.   The data portal at Iowa State University also provides a web mapping application where you can examine the data. See example below for the same area we were examining above, at a slightly smaller scale. I don’t know about you, but I could look at these historical maps and images all day if I could. They are so rich with information. Look how small the original platted town of Council Bluffs Iowa was! Also note the difference in the Missouri River meanders over time.

1836-1859 General Land Office Survey. Look at the tiny size of Council Bluffs Iowa.

It is also wonderful to be able to quickly browse a subset of the data via the ArcGIS Online map.  ArcGIS Online contains tools such as making layers transparent, adding map notes and bookmarks, and the ability to use the Iowa portal layers as a backdrop for one’s own data in ArcGIS Online or ArcGIS Pro.  In addition, as a teaching and research tool, the way the data are served in ArcGIS Online allows land use changes to be quickly observed and measured without having to download each layer. This resource continually evolves; it is updated at least every other year with new NAIP imagery soon, perhaps by the time you read this, new statewide Lidar data flown 2019-2021 will be served. In the future, they plan to add Iowa historic topographic maps at several scales and Iowa historic plat maps as well. So, whether you are seeking to examine the data in ArcGIS Online, via the web mapping application, or downloading the data from the server, you have the best of all possible worlds!

As data from portals such as the Iowa Geographic Map Server migrate to platforms such as ArcGIS Online, the data user will have additional ways to access that data.  It takes a commitment from data providers to serve their holdings onto these platforms, but data users in government, nonprofit, industry, and academia will all benefit.  Learn more about data portals, data platforms such as ArcGIS Online, and data types in our book The GIS Guide to Public Domain Data, and keep an eye on this blog. 

–Joseph Kerski