[HOT] Remote area mapping, clouds, six questions
sbower at gmavt.net
Fri May 1 01:26:07 UTC 2015
Suzan - I would like to hear from others. Here are my newbie thoughts:
ONE Small structures that may not be houses:
This may depend on the project. For #1018, Nepal Detailed Mapping 2nd Pass,
the instructions are to tag buildings as building=yes rather than as
'house'. So I have included some small buildings that may not be houses. In
a village with many obvious houses I include less of the smaller buildings,
which is inconsistent but seems reasonable given the time crunch.
TWO Geologic structures that may appear to be buildings:
I make a judgement call on these, but if I can't distinguish straight edges
then I generally don't include it.
THREE Changing other's work
I have changed others' work. For example, a way tagged as highway=track
when it really appears to be just a path, I may change it to 'path'.
However, I check the tags first to see if there's a source, in which case I
don't change it. I correct triangle buildings as they could be confusing
(the JOSM buildings_tools plugin does make it much easier to enter
FOUR Exact building shape
For larger buildings with unusual shape I correctly entered the shape. But
generally I just put in a rectangle for what I assume is the main building.
I put myself in the position of the map user - if they can figure out which
building is which, I figure that's enough.
FIVE Residential vs. all houses marked
Project #1018 *revised* instructions are explicit: "Trace ALL individual
buildings and tag it as building=yes. For clusters of building, DO NOT
enclose the whole area as one building. It is important to trace individual
structures for future damage analysis." So I have been correcting enclosed
'residential' areas with no building outlines. Your project may differ, but
I would expect consistency across most Nepal mapping projects.
SIX Up to date BING images?
Good question - the imagery date is apparently not available for some
imagery (odd). I have read that the JOSM context (right-click) menu option
to "Show Tile Info" will show the Bing imagery date, but it does not work
for me. When I "Show Tile Info" nothing happens. This link indicates it
should show the capture date:
On Thu, Apr 30, 2015 at 7:52 PM, john whelan <jwhelan0112 at gmail.com> wrote:
> small buildings building=yes, let some on the ground say its a house etc.
> If a building is not a triangle then change it to a rectangle. JOSM
> building tool is fast and very easy to use.
> Some projects want all buildings, some want residential areas and
> highways, all buildings are nice but there is a lot of ground to cover so
> read the instructions first, if you can get away with residential areas
> rather than buildings according to the instructions go for the residential
> areas and get more ground mapped in the same time.
> Cheerio John
> On 30 April 2015 at 19:39, Suzan Reed <suzan at suzanreed.com> wrote:
>> ONE Small structures/houses
>> In remote areas, lightly populated, it's difficult to see if a small
>> structure is a house or something else. I am labeling them all "house". Is
>> this correct? People live in tiny places in Nepal, less that 25' square.
>> They are hard to discern. If it looks like a building, I mark it as a
>> house. Is this good?
>> TWO Geologic structures
>> It is difficult to tell geologic structures from houses in some cases. I
>> look to see if there are similar structures in the landscape, if there are
>> fields or agriculture, then mark it as a house as I have been erring on the
>> side of marking houses and having people recognized as being there than
>> not. I want everyone on the map. This may mean I've made mistakes and it's
>> a huge boulder with a shadow. Comments?
>> THREE Changing other's work
>> Also, some of my colleagues have marked houses with triangles, not
>> rectangles. Can I correct these?
>> FOUR Exact building shape
>> Is the shape of the building important? It's often difficult to tell if
>> it's part of the house or an outbuilding or a shed near the house. Knowing
>> there are people living there seems more important, but if the actual shape
>> is important, I will go back and redo my work.
>> FIVE Residential vs. all houses marked
>> Many remote villages are simply marked with a polygon Residential Area.
>> Should I add the structures to these areas?
>> SIX Up to date BING images?
>> Also, how recent are the Bing images? In remote areas, much could have
>> been lost to landslides. I also come across areas with clouds. I can go
>> back and map these if the images are refreshed.
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