[HOT] Satellite image quality too low for mapping / not loading

Max Bainrot mbainrot at gmail.com
Wed Apr 29 11:35:24 UTC 2015

I am quite new too (having done only 1 quarter tile before for South Sudan
Ebola crisis and a little bit of mapping in my local area) and I can relate
to your frustration, what further compounds things is the countries
cultures, building style, etc can and often are different to that of where
you live/have experienced

What I do when I have a hard time identifying features is zoom in and out,
usually that helps with the low resolution and sometimes the stitching
obscures things on one zoom level but goes away on a different zoom level

Usually you can see a contrast that forms an X or a line in the center
which is the roof capping and that's a pretty good give away

Another one depending on the imagery is shadows, they give you a really
good idea of what a given structure is and how high it is (thus helping you
decide if its a short wall/hedge or a proper fence)

Also try cycling between different imagery and that can help identify
structures due to different times of day captures, etc

When I was helping out with the Sudan Ebola outbreak I found it a lot
easier to cycle between bing and the other imagery (my memory is bad
sorry), one was quite bright but low res the other was higher res but alot
darker with longer shadows, between the two it helped me identify what
looked like small buildings to be vans as well as highlight buildings that
weren't visible in the other imagery

Another thing that helps you learn is in your editor (I use JOSM, not very
beginner friendly but it's worth it IMHO) is to toggle your DATA layer (the
layer all the polygons are on) that'll make it easier to see whats beneath
other peoples work and help you learn what buildings, carports, outdoor
toilets/wells look like on the sat photos/aeriel photographs

After a short time you'll get to know certain ground features (random dirt
clearings, weird bright reflections, etc) that give away that there is a
structure there/nearby and it'll make things easier.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/hot/attachments/20150429/f83accaf/attachment.html>

More information about the HOT mailing list