OpenStreetMap

From 1ste Gimnechiske Wiki

After my father notified me that Guarapari and the area around was virgin land in OpenStreetMap, I registered and started to look for a GPS to start the work. My goal is to have entire Centro of Guarapari mapped, and in addition, all the major roads in Guarapari and to the surrounding towns as well as link it with already mapped roads, for exemple in Rio de Janeiro or Belo Horizonte.

1 My equipment
2 Contributions
3 Editing
4 Survey theory
5 Mapping Standard
6 External Links

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My equipment

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GPS

I have obtained an Garmin eTrex. I do not have much experience with it yet, my first task will be to do some road survey around the area where I live.

The GPS have three tracking modes, Normal, WAAS, and Battery Save. Battery lifetime is up to 22 hours according to user manual. Hot startup time is as little as 4 seconds, while a cold startup after a long transit (i.e. flight to another continent) is a staggering 5-10 minutes.

Technical Specs:

12 Channel (satelites)
WAAS Enabled for higher possition precission (SBAS system such as EGNOS in Europe, WAAS in North America and MSAS in Japan)
500 Waypoints
20 Routes with up to 125 waypoints each
1500 track points (instead of interval control, it uses a smart algorithm where it samples more frequently when rounding corners, and less frequent while moving in a straight line. This allows for making much longer tracks than the memory would indicate, specially when tracking from a car)
10 tracks
NMEA/RTCM and Garmin Data communication
Uses 2 AA batteries

I have a data cable with a 12V Car Power Adapter and serial line, and a USB Serial Adapter to use this GPS with rechargable batteries and a laptop computer.

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Nokia N95

I have just gotten me a Nokia N95 mobile phone with GPS function. I have little information on how to use it, but are willing to play around with it to find out if I can record tracks or upload/convert OSM maps to it. It would be an ideal pal to get possitions for various interesting points as it is much easier to edit waypoint names on a mobile than on my GPS.

Since the map offered by Nokia is a subscription service, devided in zones and information level, I am looking for ways to integrate OSM maps into my Nokia phone. In my opinion, all map systems should be possible to update independent of the main system, so that if a converter for the right format is available, the maps should be possible to load.

Appearently Garmin sells their street navigator software ported to N95. I've seen this advertised in the UK for a little less than £100. There was no information wether they where sold with maps or without. (Probably with UK & Irland)

I have also a project of making my N95 into an NMEA Device as well as making an NMEA over Ethernet driver for the phone.

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Computer

See Buzz Aldrin.

I am also planing to install Tiles@Home to speed up the tile rendering process on OSM, but havn't settled for where. Updates will come.

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Contributions

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Editing

The way I work is to put my GPS in track mode, with as high position accuracy as I find useful for the situation (Normal mode or WAAS), put the GPS somewhere safe (like in my backpack, on the dash of the car or under my kids cart, and then do the trip. When on walk I can do small detours just to cover streets I seldom take.

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Potlatch

Is a flash based editor on the OSM web page that enables you to edit direct into the database. There is a training mode you can play around with knowing that nothing will be changed in the database,. But if you have started a large edit and realizes you are running wild on it, you cannot change mode. You either work in training mode or in the live database.

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JOSM

Is a Java based editor that downloads a part of the world, and enables you to play around with the data a great deal without being afraid of interfeering with the live database. You can upload or discard your edits as you see fit.

Old versions of JOSM is almost like Potlatch, but the newer API have streamlined the software immensely. There are now menues allowing you to set all the common types of information, and you get pop-ups to fill in the valid information. There are still a few missing features, though current development plugs the holes as they pass.

If you have Java enabled on your operating system, and are registered at OpenStreetMap, you can download JOSM here. Help is found on the JOSM section of the OSM Wiki. Hotlink to latest version.

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mkgmap

When I have a .osm map of an area, and I want to check it out as a visual map, I need to convert them into another format. mkgmap is a java tool that converts .osm maps into .img files of a format Garmin uses for its maps. There is still a lot of tweeking to be done, and I havn't found a good way of making large detailed maps with searchable indexes.

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QLandKarte

This is a program made to display and manage Garmin maps, the program is open source, and works fine under my Mac OS X Leopard platform, and according to their own web page, Linux. There is supposed to be a windows port of it, but I have not tested it out, and seen no other feedback than screenshots of it.

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Survey theory

When doing map survey, the theory is to collect as much data as possible, and than analyze the data. The process is basically as follows:

Get a possition fix with as high accuracy as possible. Cross refere the fix against several different independent sources if possible.
Measure difference in height, distance and bearing between control points.
Record data as independent points with as much information as possible.
Use collected data to draw lines in a way that makes the map readable for other users. Since data is also stored in single points.

For the map to appear usable, it is important that only relevant data for the map is used, and no data of importance is ignored.

A map such as OSM aim to replace copyrighted road maps, and thus the information interesting for people on the road is of major importance. But levels of information might vary. Some places, it is enough to see where a main road leads, and how to get on to minor roads, but other places, such as in larger towns and cities, street names, oneway tracks, restrictions in height, weight or type of vehicle, and much more can be interesting and/or important.

Another level of information would be rest points and petrol stations. If a street map should have a complete function, a way of finding fuel stations and places to eat as well as the delivery adress of the cargo. Another thing that can be useful if the system is to be used in car navigation is a way of using the collected data for route planning. This information can include things such as rush hour, toll roads, priority lanes, lanes with forced routing and so on.

When entering data into the database, it is important to fill in the correct information. OSM have developed a tagging system in order to get the right symbols on the map. It is better to enter too much information into the database than too little, as the map you get out in the end is generated on the information you wish for the detail level you want on the map. Though entereing temporary or uncertain data into the database is seldom any good idea.

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Mapping Standard

One important thing to keep in mind while mapping is the level of detail. Too much detail on the completed map will makeit useless for the user, but including too few details will also do the same. The map database should contain as much usefull information as possible as this will allow the completed map to include whatever information is desired.

Therefor I have started to put in information about where to find banks, restaurants, fuel stations, beaches and much more along with the information about the streets. Oneway streets, no exit streets, street quality and much more is also of interest.

Information about street lights, speed limits, traffic survailance points and speed reduction utilities will be included in a later state as my primary goal is to get the streets itself on the map. Speed limits are generally only advicable in Brazil, so that is really of lesser importance for route planning.

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