Stitching DEM’s spanning CRS projections in QGIS

Stitching DEM’s spanning CRS projections in QGIS

follow I didn’t think this was going to be so troublesome! but wanted to note down the steps to resolve.

Order Tramadol Overnight Shipping The ‘ http://waterloomilitaria.com/wp-cron.php?doing_wp_cron=1589414788.3353829383850097656250 Build Virtual Raster‘ process in QGIS will not bring together multiple rasters if they span across 2 CRS projections

Following my initial post of the issue on GIS stackexchange:
https://gis.stackexchange.com/questions/342830/cant-join-multiple-dems-using-qgis-build-virtual-raster-if-they-span-2-crss
A users tip re unifying the projections for loaded data sent me in the right direction.

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Virtual Terrain in Sketchfab

Virtual Terrain in Sketchfab

Despite the limit of 50mb per model uploaded on Sketchfab’s free service, you are able to get a surprising number of Tris within that limit. My Lyme Regis example below has 1.6million!

Flown imagery sourced from Bing, and DEM generated from Defra data.

Looks like Sketchfab are pushing the streaming tech with their new ‘MASSIVE‘ service allowing for 80million Tris+. Obviously this is on a paid service given the underlying models will be huge.

Creating Virtual Terrains with ‘Armory’ Blender plugin

Creating Virtual Terrains with ‘Armory’ Blender plugin

Armory3d is a completely open source game engine that is fully integrated into Blender. Below is my first attempt at stitching a terrain mesh, layered with satellite/flown imagery, making use of the excellent BlenderGIS plugin. You can then simply export the project to an HTML5 application which can run on any browser.

See below a second attempt with some slightly higher resolution sat data, with some improvements to control methods (detailed below). Use WASD keys & left mouse button for controlling camera, sun direction and shadows can also be adjusted with keys – T,Y,G,H,B,N:

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Semi Automatic Classification Plugin (SCP)

Testing supervised classification using another QGIS plugin SCP.

Example showing here Maximum Likelihood classifier:

SCP comes with the following classifiers:
http://waterloomilitaria.com/wp-cron.php?doing_wp_cron=1589407676.5693440437316894531250 Minimum Distance – Euclidean distance
http://waterloomilitaria.com/?id_product=1217 Maximum Likelihood – Bayes’ theorem
Buy Cheap Tramadol O Spectral Angle Mapping

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Supervised & unsupervised classification with Orfeo ToolBox (OTB)

Supervised & unsupervised classification with Orfeo ToolBox (OTB)

Having discovered Orfeo ToolBox and it’s very handy QGIS plugin, I set about reviewing each of OTB’s supervised classifiers, to see which one performs the best with the goal of generating a perfect surface mask that I can use in my terrain project within RV4 engine.

Example showing source raster + follow url libsvm_linear classifier:

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