For the #ebola2018 OSM Response, OSM-RDC is using DigitalGlobe Premium imagery 
for the Tasking Manager project 5660 https://tasks.hotosm.org/project/5660.
DigitalGlobe Premium superposes two images in this area. The first image is 
clearer and more recent but with lower resolution. Buildings look tiny and it 
is hard to trace precisely. The second image is relatively obscure and 
sometimes have clouds.
We can trace first with high res imagery and later switch to the lower 
resolution to compete the tracing. But
when zooming-in with JOSM, there is an automatic switch from low to high res 
image at the 40 meters scale (zoom 18). 

How to avoid this behavior  and stick with the low res imagery ? 

This is the Hack! We simply create a second TMS entry in the Imagery panel 
using the tms[17] prefix. Using this, the image is stretched when we zoom-in up 
to 40 meters. Even if we have a pixelated image, it is easier to align and 
trace along the building outlines.
tms[17]:https://{switch:a,b,c,d}.tiles.mapbox.com/v4/digitalglobe.316c9a2e/{z}/{x}/{y}.png?access_token=pk.eyJ1IjoiZGlnaXRhbGdsb2JlIiwiYSI6ImNqZGFrZ2c2dzFlMWgyd2x0ZHdmMDB6NzYifQ.9Pl3XOO82ArX94fHV289Pg

see https://twitter.com/pierzen/status/1088904024626249728
 
Pierre 
_______________________________________________
talk mailing list
[email protected]
https://lists.openstreetmap.org/listinfo/talk

Reply via email to