Participants of the 1st Davao Mapping Party drove around town, took notes, asked around and practically having a wonderful time while contributing to the awesome Openstreetmap.org project. The teams covered close to 250 km adding POIs along the way as well as new access roads and subdivisions.
- team_bura(blue): Matina Aplaya
- team_dinuguan(cyan): Catalunan Grande/parts of Mintal and Catalunan Peqeuño
- team_lechon(green): Sasa/Panacan Area
- team_sulatkamay(yellow): Bangkal
- team_rapidorapido(red): Toril and parts of Buhangin/Cabantian
The team names should give you an idea what some of the guys had for lunch :). By late afternoon the teams finally convened at Chicco de Cafe which provided the mappers a cool lounge to share mapping stories, problems encountered while mapping as well as new POI discoveries. I bumped into a few issues while rendering the tracks, so I was not able to show the group the rendered tracks that day. I spent the whole sunday sorting it out. Here is the cleaned-up version guys..enjoy! (pictures and other stuff on the next blog)
davao mapping party render
Participants of the 1st Davao Mapping Party drove around town, took notes, asked around and practically having a wonderful time while contributing to the awesome Openstreetmap.org project. The teams covered close to 250 km adding POIs along the way as well as new access roads and subdivisions.
42 comments:
Guys,
What happened to the trace we made at Waan, Tigatto Area ?
Hi Art, unfortunately the data we got from you was corrupted, it could be caused by the power problem you mentioned last Saturday. Sayang talaga, but we can still use data from the paper map for updating the POIs and street names.
To Davao Mappers.
I suggest that you should invite a mapping professional into your group. Mapping is not a kiddy thing. It requires knowledge on Geometric Geodesy and GPS Systematic Errors. Without the required knowledge, doing mapping is just like wearing a blindfold blindly.
Arnel M. Domag
nth geographics and geometrics
@amdomag:hi and thank you for posting, we do have mapping professionals in OSM. And we would welcome you anytime. It may look as kiddy to you but trust me we are serious in making this work...its just that we want to incorporate fun as well. There will be errors but that's part of the whole exercise, crowd sourcing allows us to correct these errors to match known data. If you have the time you are welcome to help out.
@Avat@r: Its nice to learn that you indeed have mapping professionals in your group. I also suggest that you need to at least discuss within the group the implications of Executive Order No. 45 or the PPCS-TM/PRS92 as a WGS84 variant. Good luck.
Arnel M. Domag
nth geographics and geometrics
@amdomag: I have to wonder if you realize that GPS isn't the only method employed.
@amdomag: your expertise in geodesy must come in use locating your head inside your ass.
The professionals OSM has on board generally understand that there is a lot more to geography than archaic geometry. You clearly don't.
@anonymous: we don't have to resort to name calling and amdomag is entitled to his opinion just like you.
@amdomag: I'm pretty sure it will be easier to re-project WGS84 to PRS92 than to wait for the PRS92 project to finish. In the meantime happy OSMing :)
@anonymous: I am not posting my comment to intimidate anybody. I am just helping out here. In view of my expertise in Surveying/Mapping/GPS/GIS/Engineering/CAD/Design, I guess I know what I am talking about. I can tell you right away that in the Philippines, I cannot locate my head inside my ass using your handhelds with less than 30meters accuracy. This is due to ionospheric errors and US Degredation Policy. I can only do that using a survey grade DGPS. Geometric Geodesy is not the geometry you're talking about. It is a discipline and science used to physically and mathematically model the physical earth. If you tell me that there is more to geography, then what are they that are not geometrically referenced? If you say nice restaurants, five star hotels, airports, offices, food chains, and other installations, how can we locate them geographically if they are not geometrically referenced?
Arnel M. Domag
nth geographics and geometrics
@ amdomag
Obviously you know a lot about surveying/mapping ....
Please download a subset of our OSm data. Test/evaluate/check accuracy and topology. If you find errors (I'm sure there are) please inform us so we can correct them.
As you said we need mapping pros but passionate enthusiasts can also contribute a lot. BTW, we actually have a "kid" mapping the whole of San Pablo City.
maning
> survey grade DGPS
Can you donate tracks from your equipment?
@maning: Sorry guys if using the word kid in my first post caused rising of eyebrows of your members. I am quite taken out of context here. My intention is to provide better view on what mapping really is. Passionate enthusiasts can contribute a lot but on the basis of correct data collection procedure. If you want me to comment on your spatial database, I can tell you right away that no single point is correctly positioned if the mapping methodology is incorrect.
If you're unaware of the mapping procedure then you're indeed wearing a blindfold blindly. In that context, I used the word kid.
Arnel M. Domag
nth geographics and geometrics
@Avat@r: PRS92 was completed way back in 1992 thru AusAid. Doing coordinate transformation from WGS84 to PRS92 and vice versa is a matter of software operation but doing so requires working knowledge in mapping. This is the point I want to raise. Your mapping pro members must provide the group a glimpse of true mapping so that each member will eventually become better mappers.
Arnel M. Domag
nth geographics and geometrics
Have you actually used the data? Please do. Point me to a specific error and I will fix it. Thankfully in the OSM community we encourage people to find the errors.
All I can say is, it "fits my purpose". I can use it in my Garmin GPS as many people do (not the DGPS that you use though). I don't need submeter accuracy just find the nearest pub.
I guess deCarta was blind using osm data as well:
http://www.decarta.com/about/press_releases_2009/news_events_160909.htm
It is not productive just to say we can't do it right.
Give us real world problems and we will try to correct them. If you can provide us with dgps that would be helpful :)
> PRS92 was completed way back in 1992 thru AusAid
Are densified control points finished? Last time I asked, not yet.
@maning: PRS92 control propagation will take us forever. We can at least use the nearest PRS92 station.
I am not saying that you can not do it right. Your lines are telling me that you have indeed working knowledge in mapping. I guess we're in the same boat.
> you have indeed working knowledge in mapping
I think I just enough to trust that the crowd can do it. :)
> Sorry guys if using the word kid
Btw, when I said:
> "kid" mapping the whole of San Pablo City.
I was really pertaining to a young mapper/kid barely 17 when he started mapping San Pablo:
http://epsg4253.wordpress.com/2009/07/28/ianlopez-osm-ph-mapper/
:)
Hi guys,
This discussion is interesting, but I think I've read enough about the expertise and procedures required to make it happen. How about actually working back on the OSM data and make it as accurate as possible?
Walk the walk, as they say. :-)
@amdomag: You still don't get it - even if OSM were short on people with geodetic knowledge it wouldn't matter much. 90%+ of geographic information that is interesting to 99% of the population is in the order of "There's a postbox on the north side of Sunnyvale Drive between Avon Close and George Street."
To contribute this information you need a near zero knowledge of geodesy.
@Anonymous: My intention is to provide better direction in mapping procedure. I understand what you are trying to point out but from my standpoint, whatever you want to map out must be geometrically referenced in order to sustain the project. For me, the 90% info to 99% population ratio is inaccurate on the basis of sustainability. At this point in time, maybe the information your OSM provides is already sufficient but its rapid declination is very imminent as the requirement rises up due to daily advancement of technology. If we map out places correctly, then I can say that we can use the information forever. As a suggestion and as what I first posted, it is advantageous to your group to invite mapping professionals. They can provide the group better understanding in mapping. No offense here. It is good for every member.
@amdomag, I guess no one pointed out that OSM does not really aim to produce a definitive map of the world positioned to less than 0.1-meter accuracy--at least in the short- to mid-term. What is there now is damn useful for 99.99% of the population. Unless people get consumer GPS units that have submeter accuracy, then it should not be a bother that this street is 2 meters out of place. Also, no one expects to use OSM to measure out parcels and lots so such a high level of accuracy is not needed.
OSM is supposed to be fun after all, and not an exercise in ivory-tower mapping processes.
> it is advantageous to your group to invite mapping professionals
Point well taken. And trust me I already did when I started contributing.
But we will not wait for mapping pros to join before we start doing it. If I waited for mapping pros to join, the data may not be as rich as it is right now.
I guess people were offended because your post implied "kids" are doing what "experts in Surveying/Mapping/GPS/GIS/Engineering/CAD/Design" should be doing.
If you said something like:
"Cadastral mapping is not a kiddy thing."
Then I agree.
I've been in this industry long enough to say that we can't get any free vector data from the data silos maintained by people from Surveying/Mapping/GPS/GIS/Engineering/CAD/Design.
@Eugene: Thank you for your comment. What I am trying to point out here is not the survey grade mapping. My point is simply for your group to invite mapping pros. They will at least share the mapping concepts. At least those who use GPS must be able to understand the precision/accuracy of their handheld coordinate readouts. I guess if one knows the mapping concepts then he's in the right path. Wether we like it or not, this is the future. This is also damn good for the members.
By the way Eugene, I am pretty sure that your OSM cannot provide 2m spatial accuracy. This is again my point for mapping pros to participate in the process in order to sustain the fun you're talking about.
@maning: I'll do my part to at least inform my mapping pros friends to join in the process. Sorry for my first post.
@amdomag, thanks for clarifying your position. Unfortunately, it came off as something like the Encyclopedia Britannica saying to the Wikipedia users to learn the proper encyclopedia-building concepts. It just turns people off.
If your point is only to inform people that there is a limit to the accuracy that the amateur mapping techniques OpenStreetMap uses, then it is a valid point. After all, being a crowd-sourced project, we only have consumer-grade GPS units that is usually only accurate to 10 meters and we don't use practically any geodetic equipment in our surveying. But I don't think it takes a mapping professional to point that out.
OpenStreetMap doesn't aim to replace NAMRIA or even UK's Ordnance Survey. What we want is open/free vector map data that is topologically correct and is reasonably placed (to about 10 meters) such that users of the data won't get lost. After all, locating a store to about 10 meters (but in the correct side of the street), especially if they only have paper maps, or even consumer GPS devices, is enough. Any more accuracy is just icing on the cake. :-)
@amdomag, additional comment. You mentioned that consumer GPS is not very accurate "due to ionospheric errors and US Degredation Policy." You already probably know that the degradation policy (i.e., Selective Availability) was disabled by President Clinton in 2000 such that the theoretical accuracy obtained by consumer GPS units is equal to military-grade equipment (discounting differential GPS). It's true that there are still ionospheric effects and even multi-path effects (such as around tall skyscrapers) but most GPS enthusiasts already know about that.
You also pointed that "no single point is correctly positioned if the mapping methodology is incorrect" implying that OSM data collected currently will not be useful. Well, "correctly positioned" is a subjective term that depends on the level of accuracy required by the user. For cadastral usage, I agree that OSM's accuracy is not enough, but for practically every consumer mapping need, OSM is more than enough.
@Eugene: US Degradation Policy provided two phases of errors: Selective Availability (SA) and AS (Anti Spoofing). Adding them up provides 100m of error. When Pres. Clinton stepped down in 2000, SA was dropped for some reason. Until today, SA is still in effect. Due to this, the error due to the policy upgraded to 30m. For this reason, it is not theoritically possible for the consumer GPS to attain the military grade precision level. In addition, consumer GPS can only receive the SPS. PPS is always for the US military, allied forces, and US authorized contractors for obvious reasons. Without differential correction, your OSM can never attain the 2m accuracy.
Again, 'di ko minamaliit effort nyo. I am just suggesting something for the future of the group. After all, I am one million percent sure that differential correction (i.e. WAAS/EGNOS) will eventually be provided in the Philippines either by a private entity or the gov't for free. It is at this point that we'll understand each other on sustainability issues.
For the meantime, happy OSMng!
Hey Mapping Pros!!!!
Help me out here!!
Another thing.
Doing mapping using your own personal perception and build data for the community to use provides danger somehow. Knowing how to operate the GPS without knowing the mapping concepts can never secure the output. It is just like an architect doing engineering design by just merely using an engineering software is never equal to an engineer doing same design using same software. It is always best to follow the standard procedure by practice.
I am not saying here that we need survey grade maps. We only need the mapping procedure knowledge. It is always better to start learning the process.
Theoretically, we cannot append correctly gathered data to your existing OSM data for consistency reasons. If we reach the point where we need correct spatial information, then back to square one tayo nyan. What will happen to the data provided by the community?
@ amdomag
That's another unique thing in OSM, what we call free form tagging.
This simply mean, you can map/tag anything you like. For most people this doesn't make sense. Even for me when I started. But trust me it works. :)
In the Philippines, we follow basic conventions. But we adjust them depending on the need.
Some links:
http://wiki.openstreetmap.org/wiki/Map_Features
http://wiki.openstreetmap.org/wiki/Any_tags_you_like
@maning: tnx for the links.
@amdomag, the anti-spoofing provision is not a problem in practice. It is used to prevent spoofing of the GPS signal, and not really as a way to increase accuracy.
And I'm quite sure SA has been completely disabled. The Department of Defense has even stated that the GPS satellites that they will launch to replace the old ones will not have SA at all.
After all, it is not in the best interest of the U.S. to add inaccuracy to GPS signals. There are far too many industries (e.g. aviation) relying on GPS for them to re-enable SA. In addition, EU's Galileo (and other similar systems from Russia/India, and China) will provide alternatives.
@amdomag, I'm not yet sure you really know how OSM works. OSM data is like Wiki text--it can get refined in time as long as better (and freely-licensed) data becomes continually available. There is *absolutely* no need to go back to square one. I'm really not sure why you would say that. Please try to view the methodologies and the data schema used by OpenStreetMap before you consider the output as unusable.
There are plenty of high-profile people in the international GIS industry who see value in OpenStreetMap and its crowd-sourced approach to mapping. If you explore the OSM-world a bit, maybe then you can provide more usable constructive input from your professional mapping background, as you have suggested.
Anyway, I find the discussion interesting and I appreciate the time you spend giving your ideas. :-)
I want to contribute to the discussion I have noticed the issue here is inaccuracy.
I am a GPS enthusiast I design and build my own GPS devices the accuracies of my GPS units are 10m and 2.5m. All of these GPS devices we built came with a data logger. I donated all of my data for the past 6 years to OSM community hoping that other mappers may correct them if there are some errors.
I will be very glad to know if somebody will point out the errors so I can correct my device.
I am a cartographer for an NGO here in Mindanao for 4 years. I also use and teach CAD. By the way am an engineer that's why I am very meticulous when it comes to inaccuracies of these data.
@amdomag, if you can tell me your mapping methods/techniques it will be very helpful to the OSM community. I am the one training some OSM contributors on how to do it right.
Hew, it's hot in here!
Eugene was right SA wa disabled and the GPS SVs was already replaced with a new SVs. Increasing its number from 24 to 32 and by the way SV #32 was disables because it introduces inacuracy to the whole system (I don't need to elaborate on this). The EU was disappointed with the Selective availability of US GPS. That is why they've created their own system the Galileo it will be finished in 2011 hopefully.
Because it is very accurate I am planning to migrate to that system. Well based on the articles that I read in the internet Galileo can be accurate less than 10cm. I haven't tried it yet but it is promising.
We all agree that SA was disabled when Clinton stepped down in 2000 but we differ in views on how mapping really works. I am sharing my ideas to let everybody know how we do mapping in millimeter accuracy DGPS world. Again, I am taken out of context when I said back to square one. I am only pointing out the potential big loss to the community when the time differential correction is for free. Is OSM ready for differentail correction?
Even being an EE/ECE/Electronics/CAD Engr is not a guarantee that you indeed understand the concept of mapping. No offense here.
Mapping is for mapping engineers that's why I am sharing my ideas here.
It is theoretically impossible to attain a cm level accuracy without differential correction irrespective of satellite positioning system employed. Believe me.
Do all members really understand gps elevation readouts? Do all members really understand the difference between LatLong values and their grid coordinate counterparts? Are all members aware that straight lines in real world are curve lines in map? Are all members aware that straight lines in map are curve lines in real world? These are just few things that members need to realize in order to sustain the fun we are all talking about here. OSM mainly relies on basemaps irrespective of how it operates. That is why mapping is a primary issue here.
For those who assume that mapping is a plane trigonometry thing..it is not.
Seriously guys, I think we're just beating a dead horse now and, frankly, I've had enough of this intellectual masturbation. Unless there's specific talk on specific data points that's already in OSM, any discussion after this is just redundant and annoying.
I'd like to make a motion to close this discussion.
@Mark: I second the motion and move the discussion in the OSM mailing list. Mapping Mindanao blog has a limited audience and most mapping experts is in the mailing list.
@amdomag: Please do join our OSM mailing list
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk-ph
Why don't you share what you want us to learn so that we can attain the accuracy you want.
You already made your point I understand what you want to attain, join the discussions or open this discussion in the mailing list. And invite your peers also I know we can have a very healthy discussion there.
Mapping Mindanao is not the proper venue for technical discussions the mailing list is the appropriate venue for that. Local and international mapping experts is in the list. The people in this discussion above are also in the mailing list (I cannot say the same for anonymous).
Copy.
I'll try to find time to provide the local mappers informal presentation for me to share what I am trying to point out.
Happy OSMing. Kitakita ta mga bisaya.
By the way, kinsa naay balita kung kanus-a ipagawas ang consumer GNSS? Basin ulahi na ko sa balita.
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