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Posts Tagged ‘historical’

Historical Imagery for the entire world now available via Wayback Service in ArcGIS from Esri

July 5, 2018 2 comments

I know that many of you regularly want to examine changes-over-space-and-time with imagery and GIS for research or instruction purposes.   As of last week, 81 different dates of historical imagery for the past 5 years now reside in ArcGIS via the World Imagery Wayback service.   For more information, see: https://www.esri.com/arcgis-blog/products/arcgis-living-atlas/imagery/wayback-81-flavors-of-world-imagery/

You can access this imagery in ArcGIS Online, ArcMap, and ArcGIS Pro.  A great place to start is the World Imagery Wayback app – just by using a web browser  – https://livingatlas.arcgis.com/wayback/    A fascinating and an incredible resource for examining land use and land cover change, changes in water levels of reservoirs, coastal erosion, deforestation, regrowth, urbanization, and much more.  This resource covers the entire globe.

However, in keeping with the theme of our book The GIS Guide to Public Domain Data and this blog of being critical of the data, caution is needed.  The dates represent the update of the Esri World Imagery service.  This service is fed by multiple sources, private and public, from local and global sources.  Thus, the date does not mean that every location that you examine on the image is current as of that date.  I verified this in several locations where my ground observations in my local area show construction as of June 2018, for example, but that construction does not appear on the image.  In addition, several other places I examined from wintertime in the Northern Hemisphere were clearly “leaf-on” and taken during the summer before, or even from the summer before that.  Therefore, as always, know what you are working with.  Despite these cautions, the imagery still represents an amazing and useful resource.

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Sample from this imagery set for 30 July 2014 (top) and four years later, 27 June 2018 (bottom) for an area outside Denver, Colorado USA. 

TopoView Database of Historic USGS Topographic Maps Online

April 28, 2013 2 comments

Ever since those years I worked at the US Geological Survey, I have been hoping that the thousands of USGS historical topographic maps would someday be easily accessible for the geospatial data user.  These maps, representing an enormous investment in documenting the landscape at great detail, were compiled over nearly a 100 year period.  TopoView has just been launched that provides this type of service:   http://ngmdb.usgs.gov/maps/TopoView/.

1962 Topographic Map at 1:24,000-scale of Grand Junction, Colorado

1962 Topographic Map at 1:24,000-scale of Grand Junction, Colorado, from the TopoView database.

TopoView is intended to serve the immediate need for the older printed topographic maps to become easily searched, viewed, and downloaded.  The approximately 163,000 maps at different scales including 1:24,000, 1:48,000, 1:63,360, 1:100,000, 1:250,000, and a few others, available through this interface were scanned by the USGS Historical Topographic Mapping Collection project.   They are provided in GeoPDF and in JPG formats.   Users can use the map index interface to access a chosen location, and then browse all of the maps, scales, and formats available for that location.

Currently, the interface is best for viewing and downloading one map at a time, and the Flash interface may hinder users working on the Mac platform.  This  index does not include all historical USGS maps.  I would like to see these maps in formats that are  easier for the GIS community to use.  I also would like to see all of these maps offered as a seamless service in ArcGIS Online.

Nevertheless, I recognize that this is only the first draft of this interface and it still represents a huge leap forward.  It is a wonderful resource for comparing past to present agricultural and urban land use changes, coastal processes, changes in glaciers, the movement of and channelization of rivers, and so much more.