New answers tagged topography
OpenCycle (OSM Based) Landscape Terrain (ThunderForest) created and all credit goes to Andy Allan http://www.gravitystorm.co.uk/projects/ "The Thunderforest Platform is the 4th major revision of the systems that powers OpenCycleMap." See the tiles here around Sagarmāthā & Chomolungma (Mount Everest) ...
1) you read the data (x,y,z) from text files, shapefiles, etc., with Python only or with different Python modules (pandas, csv, Python - Excel, Fiona, Pyshp, osgeo:OGR or ...) 2) you can plot the points in 2D: with matplotlib !! in 3D: with visvis or matplotlib for example 3) you can compute contour lines (and other things...) 4) you ...
http://resources.arcgis.com/en/communities/flex-viewer/ You can find a lot of the answers to your questions through that link. On the right of the page you will see different subjects that cover the basics of what Flex is and what you can use it for.
The most likely answer has to do with different vertical datums used, as mkennedy suggests. You should probably trust the most recent published data regarding absolute elevations. When comparing elevations, at least use values from the same era. On topographic maps, elevation is the height above "mean sea level". In geodesy that is called orthometric height ...
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