Teluk Ambon

Mapping Climate Change Effects

Ambon City, Indonesia

Ambon City..........................

Getting Started

OSM License

In order to coordinate the various mappers collaboratting on this task the OpenStreetMap Tasking Manager (OSMTM) is going to need to access your OSM account. If you havent logged in when you select a grid square to edit it OSMTM will ask permision at that time. Once logged OSMTM will ask you which editor you prefer to use. For first time editors iD may be the easiest. If imagery has been provided for the grid square you have selected than you may be required to agree to the terms of a license to make use of the imagery. If a license agreement appears at this stage please review it before signing.

https://cloud.githubusercontent.com/assets/7431774/6679362/fa6672c6-cc1c-11e4-85a4-d51e5da60523.gif

Imagery

First, make sure you’re using the right background imagery. For this task, you will have multiple types of imagery to choose from. This can be found on the navigation bar on the right of the screen. For Karangetang, the default will be custom imagery. If the screen is black, try switching to Bing imagery.

https://camo.githubusercontent.com/056ceb6a29e1b26db4bab53326886d71ff70df30/68747470733a2f2f636c6f75642e67697468756275736572636f6e74656e742e636f6d2f6173736574732f393635373937312f363336303133302f62643363303838652d626334352d313165342d396565342d3431343130376530373739622e676966

Brightness

We’ll be using the default Bing aerial imagery layer for tracing. The background imagery can be difficult to see, but increasing the brightness will help. You can do this in the “Background settings” tab (Shortcut: b).

https://cloud.githubusercontent.com/assets/7816685/6696648/4a1e8fde-ccc1-11e4-92a2-800ee7e41b65.gif

Alignment

While editing you may encounter a situation where existing features were drawn based on older imagery and therefore don’t align with the current imagery. Using the alignment arrows in iD editor, you can align the new imagery to match the existing features. Now when you add new features they will be aligned with the existing ones!

Splitting A Square

Having selected your square and inspected it with the imagery in place, you may realise that there is far too much detail for one person to map. In this case you may want to split your square into smaller more reasonable tasks. As a general rule if you think that it will take longer than 2 hours to map all the tasks features in one square than you should probably split it up.

It is important to use caution when splitting squares because it comes at a cost - any usefull comments previously completed in the square will be lost.

To split your sqare simply click split the button in Tasking Manager

https://cloud.githubusercontent.com/assets/7431774/6856929/9b961d18-d3d9-11e4-8bd6-b31e8f59cd12.gif

Buildings

Tracing buildings takes good imagery and patience. Take your time and pay attention to angularity, alignment between buildings and reflecting the regularities between buildings.

Select new Area (Keyboard Shortcut: 3) in iD and put a node down at every corner of the buildings roof. Double clicking will complete the area. If you havent formed perfect right angles at every building corner don’t cry, you can ‘shift-click’ on the area to bring up the contextual area menu and use the tool to orthogonolize the area (Keyboard Shortcut: s).

Buildings should be traced as outlines of where the building meets the ground. This last piece is important. The roof outline is often easier to see in the imagery so you’ll find it often traced in OpenStreetMap but it’s wrong. If you see that the outline of the roof you traced does not align with where the building meets the ground you can ‘shift-click’ the path and use the tool to drag the path to the correct position.

https://cloud.githubusercontent.com/assets/7431774/6629871/ee37a952-c8e8-11e4-8e71-a0eda3f814df.gif

Roads

Roads

The whole process of creating a road looks is captured in the GIF to the left. Click on the image for a larger version of the image.

https://cloud.githubusercontent.com/assets/7816685/6836500/ebe377f0-d318-11e4-914a-a74a1d0e7bf7.gif

Roads Must Intersect

Roads must be connected where they intersect. Make sure the roads connect to each other where they cross. You should see a node appear at each intersection.

https://cloud.githubusercontent.com/assets/7431774/6626271/cefa345a-c8cb-11e4-8704-00197078a9e2.png

Follow the Flow

And follow the flow of roads where possible. On the left the road was traced with a “detour” for no apparant reason. On the right you see how the road tracing follows the logical flow of the road.

https://cloud.githubusercontent.com/assets/7431774/6628807/cf1f5fec-c8de-11e4-9716-cadd2d33cf2d.jpg

Tertiary Roads

highway = tertiary:

Tertiary roads are typically the most obvious, widest paths that you will see. These roads are easily seen in the imagery and will seem wide enough for two cars to pass. Tertiary roads connect towns, villages and major streets.

http://i.imgur.com/l2sUktg.png
http://i.imgur.com/D9yKOaL.jpg
http://i.imgur.com/dMo7vUe.png

Residential Roads

highway = residential:

This tag is used for roads in or around residential areas except the major roads. Generally we would want you to classify a road this way if you suspect that it is used mostly by people that live on the road. Roads lined by residential buildings are good signs. If your unsure than use 'unclassified' value.

https://cloud.githubusercontent.com/assets/2665840/6719965/236f0a88-cd95-11e4-8e8a-d02e3b04c146.jpg

Unclassified Roads

highway = unclassified:

This classification is used for minor public roads typically at the lowest level of the interconnecting grid network. Unclassified roads have lower importance in the road network than tertiary roads, and are not residential streets or agricultural tracks. Unclassified roads are considered usable by motor cars.

Tip: if a minor roads is not a residential street or agricultural track, then mark is as an unclassified road.

https://cloud.githubusercontent.com/assets/2665840/6720329/73181798-cd98-11e4-9e61-fe83df928ed4.jpg

Water Features

Rivers as Lines

Rivers are traced as lines. The entire process is captured in the GIF to the left. Please be sure to trace the river until its natural end. Click on the image to see a larger version.

http://i.imgur.com/3YZeX2S.gif

Editing Rivers

Many rivers and other water features (ponds, lakes, etc.) may already be mapped. Please take a moment to make sure that the features are traced correctly. If any appear to be wrong, please adjust the existing features as much as possible.

http://i.imgur.com/g0xp87b.gif

Validation

Validating Grids

OSM is constantly changing and no matter how filled out an area on the map is it is never done. The impression that validating a grid will mean that it will never be revisited leads many to feel intimidated by it. Anyone can validate! Just remember, do not validate your own work.

Validating a grid means that everything that needs to be done to meet the goals of the task you are working on. If the task is to map every type of feature possible and provide attributes this may be very complex and may require field verification but if the goal is to map basic features in a sparsly populated area this process is fairly straight forward.

https://cloud.githubusercontent.com/assets/7431774/6838233/436de6dc-d32c-11e4-8498-98ad7e6887fc.gif

Buildings

Now check if buildings are missing. If there are a large number missing, the grid can be invalidated. If it's only a few then it's simpler to add them as you check around.

Are the buildings correctly traced? Sometimes mappers do not trace buildings accurately & if you spot significant inaccuracies this needs correcting. You may find that a group of buildings looks like they match the shape of roofs but are displaced from where the building is in the imagery, this often happens when OSM has been traced based on imagery that has been misaligned. For the purposes of this task - unless the alignment is aggregious - leave the buildings if you suspect displacement is due to an imagery issue.

Highways

  • Highway tags are correct? Some mappers tag every highway as a track because they are not paved, but this is not a meaningful criteria in some developing countries considering the amount of unpaved roads. Check the wiki definitions, perhaps the Highway_Tag_Africa is relevant & you should research there before going any further. Road geometry.
  • Road Geometry Some mappers do not put enough details and others too much (eg a node every 10 or 20 m even if the road is straight). Delete extra nodes if they actually make a straight road weave.