OpenStreetMap

Adam Martin's diary

Recent diary entries

More on Land Use Tags

Posted by Adam Martin on 4 September 2013 in English (English)

Haven't had much cause to make another blog post in the last month and a half - mostly because I was putting into action the things that I blogged about before and got answers for. Give one thing to the OSM community (if nothing else), they will help a fellow mapper out with tagging suggestions and the like.

So I am back to the white board again for the same thing. Over the past 2.5 months that I have been adding to the project, I have inputted 400 edits to the database, mostly in the Paradise, Newfoundland area. I have relied heavily on the Wiki and the discussions to make sure I keep my tags as efficient and descriptive as possible. I am probably small potatoes with that number of edits, though I tend to average at least 100 changes / additions per edit. Still, I am adding that low level and relatively picky type of detail and any edit that is constructive is a good edit.

Anyway, I have three items that are in my view at the moment. I have been adding residential and commercial land use areas to the Town here. Among those are parks and playgrounds and the like as well as land that is unused and considered to be the property of the Town proper. In Newfoundland and the rest of Canada (I assume) space that is not sold to contractors or used in construction is considered municipal land. That land is often given over (unofficially) to the locals for their use. Looking at the land use tags (the major ones), I notice that there are several tags for land that is given for gardening or the like, but little for land that is just there and open to public access. Other lands like these have been designated by the Municipal government as "open space / conservation use zones". These include tracts of land with trees and such that are not slated for development.

The first item, then, is how to tag these areas. There is little in the land use tags that are considered the main tags for this with the except of the village_green tag. This is "supposed" to be used for space at the centre of the Town or City that is open and green. But given it's nature, I have been applying it to any space that the Town owns and permits open access to - separate from Parks and such.

My second item is related. The Town lands include mediums along the major roadway here. There is no specific tag that I see to flag the medium land as "medium" so I am considering the use of "village_green" for this as well.

My third item is a quick one. Government buildings have no specific tag. There is no civic use tag or government use tag for buildings. I am curious about what to use in cases of these types of buildings.

CanVec Data

Posted by Adam Martin on 9 July 2013 in English (English)

Looking over my area, I am proud to say that there a ridiculous number of fresh water sources. Canada is renowned as possessing one of the largest supplies of natural fresh water in the world. My province does not buck that reputation - there are a tremendous number of bodies of water, both big and small, that serve to provide all of the water needs of the population. That's the good part.

The bad part is that most of these water sources were added via the CanVec data available from the Department of Natural Resources. This is good topographical data, but it is not completely accurate. In one case, a fresh water source is itemized in that data with no corresponding information in the satellite data available through Bing. Another has a water source that is significantly different in shape from the aerial data. I am hesitant to delete the CanVec markings as they are based on professional surveys of te region. Still, the lack of any 1 to 1 consideration in it gives me pause. For egregious examples, my instinct is to plan a visit to the site - I can probably settle the matter fairly swiftly that way.

The other interesting variance in the CanVec data is that it does not indicate the type of any of the sources of water that it outlines. Which is it - a pond or a lake? A check around the Internet provides a ridiculous amount of referencing, discussion and argument as to what the difference between these two geographical items are. Some draw distinctions in terms of size, depth, movement or content while noting quite openly numerous examples that violate those criteria. Local knowledge in lieu of naming is likewise of limited use as a enormous water body in one place is a pond while another just a kilometer away at half the size is a lake.

To combat this, I have adopted the official naming scheme for water bodies as prescribed by the OpenStreetMap Wiki. Lakes are henceforth all bodies of water that are flowing (as in a stream or river) that are natural - that is, formed by local conditions independent of the influence of man. Ponds are artificial, man-made lakes that may now compose a portion of a regular waterway, but which is no less created either intentionally or otherwise.

Land Use = Open Space Buffers

Posted by Adam Martin on 2 July 2013 in English (English)

Taking a look over the municipal map for my area, I note that there is a lot of the local land area that is designated as "open space buffers". I live very close to one of these buffers - it basically denotes grass and trees that have been flagged by the local government as being meant to remain "as is" for the enjoyment of the residents. It is also meant to separate the residential sections from the industrial and commercial sections as well as the major highways.

The question is - how does one go about properly flagging this type of land use? Given that a lot of this land is occupied by coniferous forest, it would be fairly safe to designate these areas as "Land Use = Forest". However, not all of these areas actually possess trees. Some of it has been disturbed due to local construction and other parts are made up of grasses or bogs / wetlands. So, one could get rather pedantic about the whole thing and divide the ground by the sub-component - large grass areas versus tree areas versus bogs, etc. Personally, I have no trouble doing this. It's relatively easy to separate these areas once the satellite data has been aligned. Still, my first impulse is to select the major feature of the area and call it that - a forest with a grass spot within is just a forest.

That brings up another issue related to this - that of municipal land itself. I am sure it is the same here as it is in other regions. The municipal government here "owns" all lands within the administrative boundary. Land is parceled and sold to individuals for business or residential purposes. Land that is not sold in this manner remains the property of the Town. All that is fine - some of it will be given a civic use (playground / park / etc), but other parts are too small to be given a use (such as an open area near a major highway interchange. I wonder if there should be something designated within these areas. The Town grooms these areas and keeps them clear of trash and whatnot. So they are maintained directly versus an area that is slated for future use and is lying fallow at the moment. Land Use = Grass sounds reasonable - it does describe these areas to an extent. This feeds into the open space buffers idea above - these are just between sections of the Town or City proper.

Land Use versus Residential Private Property

Posted by Adam Martin on 29 June 2013 in English (English)

So there aren't a whole lot of mappers on my side of the pond (the Atlantic). This makes sense - the OSM project started in Europe and has had to gain acceptance in the North American landscape against Google Maps. The lack of mappers in general makes it such that there are not a lot of examples of people handling some of the more unique architecture that this continent sports.

For example, there is very little markings within OSM specifically for laying out trails meant primarily for offroad vehicles - Quads, trikes, etc. The closest times are footpaths with a flag for motor vehicles, though that might tend to imply that this is a road that allows cars to pass, which is not accurate. Looking around the continent, I don't see a lot of these marked and ones that are marked are not done in a manner that provides the user a great deal of information.

The same case falls for the treatment of the local land zoning. Municipalities in my areas zone land between Industrial, Commercial, and Residential use with a fourth option being held for Government facilities. This is not unlike the rest of the world, of course, but I find it odd to mark the use of the land itself, but not mark the boundaries of a particular property within that land area. The reason I find that odd is that, should the use of the land as private parcels be marked (as would seem to be reasonable) the Land Use tag will be basically covered in. So I am left with the question as to what is the best method of breaking down the use of the land and marking the plots themselves.

Fortunately, the OSM project is open enough that I can do several experiments to determine what is the best and most effective method of doing this. In that case, I have been marking some of the local residential properties in my area to test which method will provide more information to the users. I will likely document my findings in a further diary entry - for my own benefit and for others. Besides, a good clear explanation can provide one with a defensible position in terms of rationale - which is the mark of a good process, that of an audit trail.

An observation regarding Mapping

Posted by Adam Martin on 21 June 2013 in English (English)

One of the biggest threats to the act of editing on a project like this is the apathy that comes from user fatigue. By this, of course, I am referring to those users you've seen in your area with a profile and possibly an edit or two that disappears soon after. I'm pretty sure many of the mappers here have encountered this in their work over every area of the OSM database. I've certainly seen it in my short time here. Users that joined, but never made an edit to users that made single efforts and left just as quickly.

Don't get me wrong here - any edits are welcomed and anytime someone adds information to an area, even if it's not perfect, it is a benefit to the project. However, there is something that I noticed about these edits that probably drives part of the reason that these users "give up" after a short time - and that is the fact that most of them start off with something too big and exciting.

Let me explain a bit here - what I mean by big and exciting is the selection and completion of a local feature that is very visible, very famous, and very "noticeable" when it is completed. This is psychologically satisfying because the individual has "added something important" to the database. And they have, make no mistake. And for the people that join just to add that one thing with a singular purpose, their job is done. But to the other enthusiasts, after getting in that super important thing, they are faced with the spectre of what the real job with the maps entails. Thousands of adjustments, correction, additional, alterations and improvements that change the map from a pretty picture into an accurate geographical representation of reality.

It is an unfortunate fact of reality - not all editing is glamorous. It is to those that can stick to that sort of work and plod their way through it that the map has made it to the state that it has reached now and what it will become in the future. As I said, it is just an observation, but it is an interesting one.

Methods

Posted by Adam Martin on 20 June 2013 in English (English)

From my readings of the Wiki and the OSM forums, I get the idea of the general method that most users follow in editing the map is to start with the biggest connective feature of any map - the roads. Just ensuring that each road has the correct positioning and shape is intense work. But it is vital work as these roads literally represent the "veins" of the map. All other features flow from these veins.

I plan on following that method - that is, focusing on the roadways before the I move onto the next major feature, the buildings. With that said, I am not going to follow that to the letter. I work as an auditor in my regular job. One of the keys to that line of work is a meticulous attention to detail - I need to be observant and very focused on the work at hand. I have found over my years doing this job that one of the tricks to staving off boredom or the related feeling of tedium is to switch it off for a different type of the same. Basically, I find it beneficial to "break" the tedium by changing it up for a short period. It recharges my batteries and allows me to launch into more without getting cross-eyed. I will do the same for my mapping work - switching to a few buildings here and there to stop myself from abandoning the effort.

I am also pretty new to this process so I'll probably start trying out some of the other mapping features over time. Makes the process even more interesting to the fledgling mapper.

Interest in Editing

Posted by Adam Martin on 19 June 2013 in English (English)

I have long had an interest in mapping - both in the geographical sense and in the computer gaming sense. I attempted to edit the Google Maps with their Map Maker service, but found the whole ordeal to be a nightmare of bureaucratic mangling and somewhat insular approvals. Easy to "make a change" on the map (relatively), but it is brutally difficult to actually get it seen by other people. Worse still were the changes that I made that were rejected because of some inane flap from their Bot service.

But thankfully I found OSM - ready and more than willing to accept my edits. Edits that would appear on the actual mapping database within minutes instead of weeks, if it was approved. I know the classic counter-argument to that is the idea that people will get in and troll the maps, but that is an act of a child. I am a 33 year old man - I have no time for such nonsense. If I draw a building outline and state that there is a coffee shop there, you can be sure that is exactly what is there. Community review will handle anything odd, of course.

I hope to make several contributions to the OSM data - my first edits have been corrections and refinements to existing data. There are not a lot of users in my area, but that's fine. I love the idea of plugging away at the map alone to an extent.

Older Entries | Newer Entries