Thanks for the tip. I will check.....
The project is not available now, long market story. But I know the place by heart.....
That hole after the ridge was a nightmare for me because of a critical chain of exclusion ( a pipe, crossing the mountains, at a limited angle, a maximum elevation, etc).
But as I wrote before, I made some merges of the two data sets SRTM and ASTER. The result was something like a smallpox affected skin, but with a perfect rectangular pattern. Obvious a offset of the elevations. I observed this on large surfaces.
Sorry to discard all, so I cannot say which one one was up and which down, I think I remember, something of meters order of magnitude, almost 10 m.
Ambitious........ To merge SRTM and Aster....
Personally I worked with SRTM and ASTER somewhere in west Africa, near the Ecuador, - 2 latitude area. 5000 sqkm the biggest exploration permit.
ASTER was full of artifacts, something like "small circular spots" (difficult to understand the origin, perhaps the clouds traces) and lines/shadows in a rectangles grid, probably the connections at the limit of the original data tiles, the swats. Also, big "holes" with more than 200 m elevation drop, almost vertical, from a mountain ridge.
Not existing in SRTM; because it was a critical area, we checked with a "macete" team in the the jungle; no such huge hole there.
Also it was a regular elevation offset, some goods meters among the datasets.
Joining the grids I obtained largely a DEM showing me the relief, but full of spots (dots) in a regular grid. The dots were obvious generated by one of the grids, with an vertical offset.
A new set of 10 ArcGIS Pro lessons empowers GIS practitioners, instructors, and students with essential skills to find, acquire, format, and analyze public domain spatial data to make decisions. Described in this video, this set was created for 3 reasons: (1) to provide a set of analytical lessons that can be immediately used, (2) to update the original 10 lessons created by my colleague Jill Clark and I to provide a practical component to our Esri Press book The GIS Guide to Public Domain Data, and (3) to demonstrate how ArcGIS Desktop (ArcMap) lessons can be converted to Pro and to reflect upon that process. The activities can be found here. This essay is mirrored on the Esri GeoNet education blog and the reflections are below and in this video.
Summary of Lessons:
Can be used in full, in part, or modified to suit your own needs.
64 work packages. A “work package” is a set of tasks focused on solving a specific problem.
370 guided steps.
29 to 42 hours of hands-on immersion.
Over 600 pages of content.
100 skills are fostered, covering GIS tools and methods, working with data, and communication.
40 data sources are used, covering 85 different data layers.
Themes covered: climate, business, population, fire, floods, hurricanes, land use, sustainability, ecotourism, invasive species, oil spills, volcanoes, earthquakes, agriculture.
Areas covered: The Globe, and also: Brazil, New Zealand, the Great Lakes of the USA, Canada, the Gulf of Mexico, Iceland, the Caribbean Sea, Kenya, Orange County California, Nebraska, Colorado, and Texas USA.
Aimed at university-level graduate and university or community college undergraduate student. Some GIS experience is very helpful, though not absolutely required. Still, my advice is not to use these lessons for students’ first exposure to GIS, but rather, in an intermediate or advanced setting.
How to access the lessons: The ideal way to work through the lessons is in a Learn Path which bundle the readings of the book’s chapters, selected blog essays, and the hands-on activities.. The Learn Path is split into 3 parts, as follows:
Solving Problems with GIS and public domain geospatial data 1 of 3: Learn how to find, evaluate, and analyze data to solve location-based problems through this set of 10 chapters and short essay readings, and 10 hands-on lessons: https://learn.arcgis.com/en/paths/the-gis-guide-to-public-domain-data-learn-path/
Solving Problems with GIS and public domain geospatial data 2 of 3: https://learn.arcgis.com/en/paths/the-gis-guide-to-public-domain-data-learn-path-2/
Solving Problems with GIS and public domain geospatial data 3 of 3: https://learn.arcgis.com/en/paths/the-gis-guide-to-public-domain-data-learn-path-3/
The Learn Paths allow for content to be worked through in sequence, as shown below:
You can also access the lessons by accessing this gallery in ArcGIS Online, shown below. If you would like to modify the lessons for your own use, feel free! This is why the lessons have been provided in a zipped bundle as PDF files here and as MS Word DOCX files here. This video provides an overview.