[HOT] Good data from a poor quality image of Nepal

Pierre Béland pierzenh at yahoo.fr
Mon Jun 8 23:30:41 UTC 2015

Hi Suzan,
interesting these various ways to play with the screen adjustment and find more details. Yes it is important with poor quality image to analyze the image, plus get our eyes adapted to this image. More challenging but provides a great satisfaction.

A statistic that shows the great effort that the OSM community made for the first 5 weeks of this Nepal response: we traced nearly 1.4 million buildings.


      De : Suzan Reed <suzan at suzanreed.com>
 À : "hot at openstreetmap.org Team)" <hot at openstreetmap.org> 
 Envoyé le : Lundi 8 juin 2015 19h03
 Objet : Re: [HOT] Good data from a poor quality image of Nepal
Using this method I was able to see many buildings, roads, and paths in a number of validated tiles. This is worrisome, especially when it's fixable. 


On Jun 7, 2015, at 2:08 PM, Suzan Reed wrote:

Dear Friends, 

As we know, many images of Nepal are poor and it's daunting if not impossible to see what's there. 

I used the System Preferences on my MacBook Pro to create a new display profile for my monitor, not for color, but pushing the monitor to show greater contrast. (This differs from image to image.) I was then able to see more of what was impossible to see before. Because I am familiar with village images in Nepal, I was able to locate and map a village of 100 buildings, and to find many more buildings, paths, and tracks on the task I was working on. 

A high resolution TIFF or png screen shot and almost any photo adjustment software, for instance something that comes with a phone or computer, can increase contrast. But I understand taking a screen shot and adjusting it violates the licensing agreement, even if it's for my own use to help me see what's there. 

However, the monitor adjustment hack, although not at all as good enough as a software solution, proves adjusting the entire map makes it possible to map using these images. But, the monitor adjustment is a hack, not a solution. 

It is possible hundreds of buildings, entire villages, and many roads, paths and tracks are being missed, and therefore hundreds of people will be left out of the HOT maps. That would be a terrible tragedy affecting real people and their lives. What we do matters to the lives of real people on the ground, something easy to forget when squaring buildings. 

Given the enormity of the crisis, it may be the licensing company would be open to having these specific images of Nepal adjusted for contrast. You never know until you ask. 

Fingers crossed someone will make the calls and ask. Someone once told me, we aren't psychic, but we often think we know the answer before it's asked. Surprises do happen. 


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