@pnorman,

Great information, thank you. By the way, is there any Wiki page, where links to studies like this one are collected?

Мне очень не нравится, когда мои слова искажают и вырывают из контекста. В конце заголовка, который вы перевели и процитировали, стоял знак вопроса, то есть утверждением это не было, это было вопросом, который я изучал с разных сторон в дневниковой записи, которая была таким образом озаглавлена. Это было приглашение к тому, чтобы подумать, обсудить и рассудить, а не конечный вывод. Я действительно не в восторге от результатов внедрения редактора в Maps.me, однако предпочитаю сам выражать свои мысли по этому поводу так, как считаю нужным, стараясь всегда избежать неверной трактовки, на сколько это возможно. Чего и вам желаю.

Ну и что это за ерунда?

Unfortunately, this valuable observation is still far from being scientific. I mean, now, we have some information about what happens if you do contact new mappers, but we still have no idea what happens if nobody contacts them.

My hypothesis (and I admit, that I’ve never tried to confirm that) is that percentage of people, who will eventually turn into a recurring mappers or active knowledgeable mappers is not only low (as we know it from statistics), but also barely depends on anything except mapper’s own will to learn.

Informative welcoming message can probably save some time, giving useful links, since even those who have certain experience sometimes have no idea about area-specific resources. However, judging by my teaching experience, not related to OSM, it is impossible to change someone’s attitude towards learning in a few words, while ability and desire to learn about OSM are still very important requirements for becoming an active mapper or another type of OSM contributor. (I probably don’t have to explain, that existing ignorance can’t be cured this way either.)

Another part of my hypothesis is that current documentation is usually enough to learn about general principles of OSM. There are certain exceptions: local resources are not necessarily presented well there; certain forms of documentation, such as brief “cheat sheets” (Map Features pages) can have negative influence, since some people never read further descriptions, while Map Features pages don’t contain any in-depth explanation of concepts. There are people with more “social” style of learning, who prefer asking over reading, but to help them, it’s usually enough to make them aware of available communication channels, such as mail lists, forum, chats, etc.

When someone starts talking about investigating certain claim, isn’t it required to define criteria, required for confirming it? I mean, like, presence of straight geometric shapes, for example. Or equal dimensions (linear or angular).

This problem is already solved. Install utilsplugin2 and use Add node at intersection command.

@Warin61, Since https://wiki.openstreetmap.org/wiki/Tag:waterway=river and similar tags have never been described in documentation, as something, related to clearways, no single sane person will ever use this geometry for waterway navigation. Use of unofficial third-party data for navigation, which could affect safety, is often explicitly prohibited by national regulators. So, I wouldn’t worry about that.

I’m guessing, there is no rivers with center line mapped according to bathymetry in OSM.

@imagico,

It would be great to have some common spatial functions in JOSM some day, similar to ones of PostGIS, in form of more or less visual interface.

@Minh Nguyen,

As a bottom line for what you just said, I’d like to add, that data structures have objective criteria of technical usability and accessibility, while usability for people is very subjective and varying from person to person. Therefore, having limited resources, it’s easier to meet objective criteria than to please everyone’s personal taste.

Someone could say, that adding certain abstraction layer between OSM data and end user (I mean: developer of rendering engine, map style, spatial data product) can solve any issue of data structure by pre-processing it. And it is currently required anyway to handle some list values. But there are several things to keep in mind:

• It’s a fact, that only a few application developers actually were brave enough to dive into development of value list support. It demonstrates, that such practice is undesired for developers and end users of data, while OSM doesn’t exist for itself - it exists exactly for these users.
• Abstraction layer can be successfully added not only between OSM data and its users, but also between mappers and data. I mean, editor presets, “tag-less” interface similar to iD and so on. And, ironically, having better data structures in database makes it easier to create and support this kind of abstraction layer for editor developers.
• Complexity level of real-world entity and its description (model) can’t differ significantly. Complex entity always has complex model, if there is no way to get rid of some of its features. So, there are and there will be more complex data structures (tagging schemes), requiring smart editor GUI to make mapping process easier.

Because of all these reasons, technological quality of data structures (tagging schemes) is more important than how appealing it is for mappers, who’d like to type it manually. Without better editor interface only a few people will use such scheme anyway, regardless of its style.

@GinaroZ,

First of all, I’m not discussing any specific tags here. I’m also not looking for a solution, how to deal with existing schemes utilizing value lists in any particular software or service.

For sure, working with lists isn’t impossible and I didn’t say it is. However, if you count all technical expenses, caused by this scheme, you will see its bad side.

I think it’s some curious coincident: two consequent diary entries (this entry and previous one) are talking about literal strings as values and bad sides of regular expressions.

Очень информативно.

@Sanderd17,

Sentinel 2 data actually can be used to update populated places too. For example, in Moscow, Russia many construction sites can only be kept up to date by using this kind of imagery. Active logging, which goes on around Moscow, also can’t be traced from archive WorldView imagery, since it’s several years old.

Speaking of lobbying, it’s it might be realistic in case of place where you live, but many countries don’t have that kind of luxury (or people, who have will and time to do that).

Reasoning in this diary entry is demagogic and often - false. Anecdotal evidence (someone’s “scary story”) as well as its sensationalism are another two bad things.

If you trying to convince people to do something good, please, for the sake of common sense, try to avoid discrediting the whole idea by using this kind of reasoning.

There are several other projects, dedicated to cell tower mapping, and there is no sense in trying to do what they already doing in one more project.

My Portugese is not that good, but “ventosa dupla transporte vidro” keywords gave me some links, including one to www.mercadolivre.com.br, which says, it’s widely available in Brazil. Price starts from 30 BRL not including delivery, but since it’s so widely available online, it should be in regular hardware stores too. (There are cheaper ones, but they are small and single, not double).

For sure, I’m not forcing you to do anything - it’s completely up to you, but your camera costs way more than that, as well as car body work in case if it will bump into hood or fender at pretty high speed and leave a dent.

I have a friend, who worked for car review magazine for more than five years. Now, they have fancy factory-made mounts, but before that, they successfully used removable suction cup handles made for carrying sheet materials such as glass, metal and plastics. This handle has two large suction cups, operated by two latches. Standard bicycle mount can be used to attach camera to handle itself. Suction cups have certain flexibility, so it’s easy to mount it onto any close-to-flat surface, such as hood or roof. If surface and cups are clean, no damage to paint will occur. Two independent mounting points decreasing possibility of accidental mount disengagement.

Another good paper on band combination visualization: Displaying and Stretching 16-bit per Band Digital Imagery from USDA FSA Aerial Photography Field Office. Gives perfect illustration, why understanding is required.

Completely support that.

Own experiments are required to learn how to get useful result, while fundamental principles of band combination are explained many times in countless sources with different level of complexity.

Nice article, by the way (and full text is available): First Experience with Sentinel-2 Data for Crop and Tree Species Classifications in Central Europe

@imagico,

That’s basically what I’m trying to say (besides other things) regarding of Sentinel processing. Technically, it’s easy; anyone can learn it with experience; any decent result can’t be achieved by following simple “brainless” workflow. However, Zverik only wants to hear what he likes and prefers to blame “rude smart ass professionals” for not willing to write step-by-step instructions and keeping information secret. That’s hilarious, because where we, “professionals” (I’m just total amateur, by the way) have learned it from? Obviously, from fundamental sources (not tutorials) and own experience.

I’m pointing on fact, that GPS has both types of error, but you can observe them both (and use median line of point cloud for more or less good averaging) in particular case only if number of measurements (tracks) is statistically large. Otherwise, it’s just guessing.

Since GPS carrier frequency is high, it could be enough to have conifers on the left and broad leaf trees on the right from path to get certain grade of systematic error. So, it happens not only in urban areas or mountains.

Relativism, as a part of reasoning (“something is better than nothing”, etc) is okay only if objective is clear. I mean, if you want to say “somewhere here is a path”, you can use even one track. But if you want more or less precise data - you obviously need more before adding anything to map.

Another thing, having just several tracks, it doesn’t make sense to trace every wave of them - these are just imaginary details, caused by deviations of measurement.

These are just simple things about GPS measurements everyone should have in mind when tracing tracks, but surprisingly, people in general have quite unrealistic understanding of this technology. So, it worth mentioning, I believe.

Just keep in mind, that several tracks are not reliable enough for averaging. I have it explained and illustrated in this diary entry.