Talk:Armchair mapping

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Discuss Armchair mapping here


Reflecting consensus

I've tried to be balanced and reflect community consensus on this page, or at least present two sides of the coin. What do people think? It's a tricky one because many people will read the page and not really grasp why it is so negative towards armchair mapping, meanwhile I know some people rail strongly against armchair mapping in any circumstances, and so for them this page is not denouncing it negatively enough.

Currently the page is missing some examples of armchair mapping projects. Adding these will swing it a little more towards the positive

Overall it's probably time we try to agree upon what is accepted and what isn't. This page should help us do that.

-- Harry Wood 15:34, 31 January 2012 (UTC)

Hmm ok from this point of view I guess it's ok, as you explicitly try to show it in black/white. Let's see if it turns out to be useful :) --!i! This user is member of the wiki team of OSM 16:07, 31 January 2012 (UTC)

I didn't think it gave a proper representation of this modern type of mapping. Added some positive aspects of armchair mapping as there were none previously. Also I do disagree with the disadvantages posted and could easily argue against all points and it implied you cannot. Did you mean "difficult to argue for" rather than "difficult to argue against"?

e.g. having a map discourages mappers. For me I would never have got involved in this project if my home city was a blank canvas. I discovered the project maybe 5 years but nothing was on the map and that discouraged me to join. The work and learning curve to populate blank city from no knowledge of the project is huge. It was only years later when we had many roads did I contribute.

And frankly saying "often" armchair maps vandalise the map is just offensive. --Rovastar 01:05, 6 March 2012 (UTC)

Well first of all "Vandalise" is a strong word. Vandalism is intentionally ignoring the consensus norms of the OpenStreetMap community. Simple mistakes and editing errors are not vandalism. I didn't use the word vandalise. You're making that up. What I've written is "Armchair mappers have often been found to be damaging or undoing the hard work of surveying mapping contributors". Sorry if you find that offensive but it's true. It's a simple statement intended to spur people to think and to direct armchair mappers to follow the guidelines.
A lot of the points are intended as justification for why we need guidelines. The page doesn't say "You must not do armchair mapping". In that sense I've really tried to reflect a balance of points of view, because there's plenty of people involved in OpenStreetMap who think just that. They think the guideline should be "Do not do armchair mapping". I have a more balanced view myself, but I can see their point of view.
I think your new "advantages" section is good and helps this page to be more balanced. I also had in mind adding some examples of armchair mapping initiatives too.
I think the guidelines section needs to remain near the top of the page though. That's really the main point of this page (whether you agree or disagree with armchair mapping there are ways it should be done more carefully)
-- Harry Wood 10:59, 6 March 2012 (UTC)
To be honest I felt the tone before was an old school don't do armchair mapping. I know you were trying to appease the old school mappers who do everything via the expensive GPS devices and use no sat imagery and who are over sensitive about their data and tbh think they don't want a completed map as they like editing it too much. So just trying to balance the page out, there are a lot of armchair mappers out there and I don't want to discourage them. damaging/vandalising are all negative terms and saying often when someone does this is is damaging has a tone of "don't do it". I changed "often" to "occassionally" as I think this is more realistic. --Rovastar 13:44, 6 March 2012 (UTC)

"difficult to argue against" is not really what I meant. Of course people repeatedly argue against the criticisms of armchair mapping. Arguing is not difficult :-) I've changed it to "difficult to prove or disprove" and also given that whole paragraph a bit of rewrite. People have differing views of the relative value of armchair mapped data. Perhaps that is where disagreement really lies. I think for pro-armchair mappers, the arguments about psychology of the new users seem wooly and insignificant because they see their data as almost as good as somebody mapping the neighbourhood locally - Harry Wood 13:42, 14 March 2012 (UTC)

Issues in Texas

Thank you so much for adding this page, Harry. I think that it's more than mere coincidence that this page appears a short time after I had an issue with an out of area mapper here in Texas. I really appreciate all of your help, and it's a great "rules of the road" page for the community. --Homeslice60148 20:48, 30 January, 2012 (UTC)

Glad you like it. It's certainly my intention that you should be able to link to this page to point out to armchair mappers that they should be taking more care and not trampling over your more valuable local contributions. It's great that more people are getting involved in mapping the U.S. properly, with local contributions nowadays. But in the U.S. we've actually been promoting armchair mapping for years now in the form of TIGER fixup, and there's still massive areas which can benefit from the attention of people operating "out of area", because the data needs fixing up and the aerial imagery is hi-res enough to allow it. So I guess there's a balance of opinions about this, but one thing's for sure: Armchair mappers should not go messing up valuable surveyed data. Perhaps if we can invent tools to help armchair mappers recognise areas of local survey-based mapping, then this will end up being particularly useful in the U.S. -- Harry Wood 01:16, 31 January 2012 (UTC)

Some notes I made

When I did a bit of armchair mapping to add missing road names in some parts of the UK from bing/os opendata sources, I set myself a few ground rules, detailed here. Sorry for the strange order - by adding newer stuff at the top you have to read the sections there in a strange order. --EdLoach 17:26, 13 March 2012 (UTC)

Imagery can be wrong

Because of the reasons you explain. BUT. The "survey on the ground" can be wrong as well sometimes. I've seen outdated or inconsistent street signs or highway numbers in the "real" world as well. This is quite rare but seen enough to say "the ground survey is not always the truth". In such cases, the tags 'old_name' or 'old_ref' are helpful. --Pieren 13:32, 14 March 2012 (UTC)

There's all kinds of discussion about street names as you know ( Talk:Names ) These are an awkward case. But most data should be Verifiable on the ground, and so "survey on the ground" is the way to get to the truth.
People who survey on the ground ("Normal mapping" as opposed to "armchair mapping") do not always do a perfect job of it. Mistakes are made.
How to fix those mistakes is an interesting question. Really the best way to fix them would be to go on the ground again. I'd be very reluctant to say that data should/could be fixed by armchair mappers. Note: I'm not saying things can't be fixed by using aerial imagery after the fact, by the same people who were on the ground. But using aerial imagery to fix stuff without going there is problematic really. You have no way to know if you are in fact screwing up valuable data.
-- Harry Wood 14:08, 15 March 2012 (UTC)

"Further information"

Somebody added a link to Roof modelling, and that gave me the idea that there ought to be a single page that gives not only an overview of things one can deduce from imagery, and what to watch out for when interpreting imagery, but also with example images (of different quality imagery!) and their plausible wrong and correct interpretations. Various general guidelines are mentioned in at least Mapping_techniques, Yahoo!_Aerial_Imagery, Yahoo!_Aerial_Imagery/Accuracy, Bing#Precision, Accuracy and Roof modelling - also a short bit at Beginners_Guide_1.1.2 - and each of these have a different set of guidelines. I'm quite certain these are not the only pages already written. Aerial Imagery caveats, maybe?Alv 18:18, 14 March 2012 (UTC)

Yeah. There's a page called Using Imagery which popped up recently (more recently than this Armchair mapping page). It needs work, and we need to figure out the scope and avoid too much duplication. "Using imagery" is more broad than "Armchair mapping" of course, because many/most mappers use imagery along with their data they have surveyed when they contribute (Using imagery but not armchair mapping). So then we have the problem that things like details of how to get the offset right, perhaps belong on both pages. -- Harry Wood 21:23, 28 April 2012 (BST)