Re: [HOT] Fwd: mapping standards
Hello Pierre, hello John! Thanks a lot for your quick and detailed replys! I did't expect a simple answer anyway ;-) Your hint, John, that HOT-mapping is more standardised makes the guidelines (http://wiki.openstreetmap.org/wiki/Highway_Tag_Africa) more than only a rough orientation for us. And I agree with you, the most important tasks to work on is the traffic network and that's what we actually concentrating on. We're just trying to figure out how to do it as right as possible. I found conventions that seem to underline the HOT-approach: In some situations it is however appropriate to base the tag value on the physical attributes of a highway: - The official classification for the road is not known or easy to establish. - The administrative classification for a road does not match the physical attributes for some historical reason. (https://wiki.openstreetmap.org/wiki/Highway_tag_usage) So, is there a general favour for tagging based on physical attributes instead of administrative levels? Would a wide frequently used and well biult county-level road get a secondary-tag although it belongs to the 3rd administrative level? In fact, our work has been initiated by a group of Cameroonians running a small non-profit association for setting up connections and provide support in terms of research and education. They are helping us translating our questions and transfering them to local people they know. So we asked about official criteria the government uses for classifying their roads and for establishing a network hierarchy. We've been told that the guys have already approached the administration and are waiting for an answer. What ever this answer might be, we hope that some of the criteria we'll get back can be applied in our work based on satellite images. But we're still waiting ... John, you've mentioned a list of tasks. Where can we find this list? Does this list indicate, what features or regions are under contruction? We found a reasonable amount of undefined objects (mostly roads) in our area which are not visible in OSM or the iD-Editor. Is there someone working on these objects? What shall we do at locations where we know that these exist? I'm afraid of finally ending up either with an inhomogeneous, incomplete mapping result or with objects being mapped twice after the undefined showed up again. So far for now! Thanks again for your support! kamak Am 2014-11-09 19:49, schrieb john: I'm currently mapping #684 - Polio outbreak and Ebola preparedness, Meiganga, Cameroon and I must confess I have questions about the project. I can understand French especially a European or African accent so the video was useful to some extent. To me HOT is different to normal OSM. In normal OSM people basically do their own thing. Sometimes they use standard tags but there is a wide range and style of tagging. HOT prepares maps for a particular target audience so to my mind takes a more standarised approach. What I haven't seen is a list of requirements. There is a list of tasks but that isn't the same as a list of requirements. For Meiganga there are thousands of buildings to be mapped. I understand the idea that ideally each building outline shape should be carefully mapped but realistically with the JOSM building tool I can approximate the building size in two or three seconds. To carefully trace the outline takes me twenty seconds or so. If I look at some tasks I see someone has mapped three buildings then given up. They are beautifully mapped but when there are another 98+ buildings to map in the task and another 180 odd tasks to do? Yes we are using volunteers so their time doesn't cost us anything but mapping buildings is tedious and how fast do we want the information to be made available and how accurate do we need it? What exactly is the requirement? I think for this you need to go back to the AID agencies and the Cameroon government cartographers and get them to make a list and set priorities. Can we tackle the tasks differently? The road network and water really need to be done first. It's better to have as few a number of segments in a read as possible. That way when you tag the name you only need do it once. Water, in a task its difficult to see if its a river, ditch or a clump of trees sometimes. From further out you stand a better chance. Also if we break the tasks down then the grunts, sorry less skilled volunteers, can tick off the task as done when they've mapped all the houses and paths. If they are daunted by the idea that they have to map all the residential and non-residential buildings and forests before marking the task done they maybe reluctant to tick the box and we end up with lots of tasks mapped but not ticked as done. Then we get to the quality of the map. It sounds dumb but different satellites have different accuracy. DigitalGlobe’s WorldView-2 is one of the better ones. There was
[HOT] Fwd: mapping standards
Regards to all list members! I'm one of a group of cartography students from Germany. One of the courses in our master program deals with OSM mapping of the Region West in Camerun. We're aiming on two things: Final goal no. 1 is to fill gaps and correct existing routes and their attributes mainly based on satellite imagery. Secondly, goal no. 2 is a final one, too, but contains basic work prior to our mapping process: We want to find or develop tagging standards for Camerun which shall finally become available at the OSM-page Tagging guidelines by country. So we're all together 15 students that start working on the road network. BUT that's important for us: 1. We would like to get in contact with mappers who have already worked on that before or doing it right now. We would like to share experiences in order to avoid working and discussing on things that others have already done or that has been already discussed. And of course: We want to avoid interfering with mapping activities that are going on right now in that region, but rather combine our efforts for the next few weeks in order to produce a consistent output. 2. On which basis have the existing routes been tagged before? Where there specific agreements for Camerun? What about the usability of the criteria proposed on the Highway Tag Africa-page in the OSM-Wiki which is initiated by HOT? What about the usability of Référentiel Géographique Routier which can be seen on www.geocameroun.cm? Finally, we would like our contributions to be substantial in order to develop a standardized and reliable geoinformational fundament on which further mapping can be consistantly conducted. So we're looking forward to any advices! Best regards from Germany! kamak ___ HOT mailing list HOT@openstreetmap.org https://lists.openstreetmap.org/listinfo/hot
Re: [HOT] Fwd: mapping standards
About the video of the Eurosha volunteers, I forgot to add the link.This is https://www.youtube.com/watch?v=saFsT558Xbo Pierre ___ HOT mailing list HOT@openstreetmap.org https://lists.openstreetmap.org/listinfo/hot
Re: [HOT] Fwd: mapping standards
I'm currently mapping #684 - Polio outbreak and Ebola preparedness, Meiganga, Cameroon and I must confess I have questions about the project. I can understand French especially a European or African accent so the video was useful to some extent. To me HOT is different to normal OSM. In normal OSM people basically do their own thing. Sometimes they use standard tags but there is a wide range and style of tagging. HOT prepares maps for a particular target audience so to my mind takes a more standarised approach. What I haven't seen is a list of requirements. There is a list of tasks but that isn't the same as a list of requirements. For Meiganga there are thousands of buildings to be mapped. I understand the idea that ideally each building outline shape should be carefully mapped but realistically with the JOSM building tool I can approximate the building size in two or three seconds. To carefully trace the outline takes me twenty seconds or so. If I look at some tasks I see someone has mapped three buildings then given up. They are beautifully mapped but when there are another 98+ buildings to map in the task and another 180 odd tasks to do? Yes we are using volunteers so their time doesn't cost us anything but mapping buildings is tedious and how fast do we want the information to be made available and how accurate do we need it? What exactly is the requirement? I think for this you need to go back to the AID agencies and the Cameroon government cartographers and get them to make a list and set priorities. Can we tackle the tasks differently? The road network and water really need to be done first. It's better to have as few a number of segments in a read as possible. That way when you tag the name you only need do it once. Water, in a task its difficult to see if its a river, ditch or a clump of trees sometimes. From further out you stand a better chance. Also if we break the tasks down then the grunts, sorry less skilled volunteers, can tick off the task as done when they've mapped all the houses and paths. If they are daunted by the idea that they have to map all the residential and non-residential buildings and forests before marking the task done they maybe reluctant to tick the box and we end up with lots of tasks mapped but not ticked as done. Then we get to the quality of the map. It sounds dumb but different satellites have different accuracy. DigitalGlobe’s WorldView-2 is one of the better ones. There was presentation by *Kevin* Bullock on the subject at a SOTM US recently but the video seems to have disappeared. If you can find it the relevant bit is 15 mins in for 90 seconds. If you look at in task 684 you'll notice that the Bing imagery and the Mapbox imagery don't quite line up. Some mapping has been carefully done from Bing and some from the DigitalGlobe imagery. Can we clean the data up? Interesting question, from a satellite imagery I'm unable to tell if a building is residential or not, however many buildings mapped from satellite imagery are tagged building=house rather than building=yes. I would suggest that if building=house is tagged from satellite imagery this be changed to building=yes by bot but only if its the initial tag on the building. Some small blobs might be a car or an outhouse. Perhaps it might be worthwhile to scan for a minimum size building? If we go back to the idea of requirements again it seems likely that to get a better map we need someone on the ground. worldbicyclerelief.org do reasonable bikes for Africa, I'm from a technical background so I like the idea of some sort of computing device to enter data on. Smart phone perhaps or can we work with one of the local schools? I assume that Internet access is not ideal but text messaging might work. I'd envisage compressing / encoding the information so it fitted into the constraints of text messaging to get the updates back. It would need some programming effort on the device and at the other end but there are a large number of programmers around OSM. This may well be already sorted out but as a mapper I'd like to think that my efforts were used rather than left waiting for someone on the ground to do their bit. I might even dump some cash into a charity that could sort this sort of stuff out and yes I know its not as instant as a bag of flour but it is important to have the infrastructure in place. Cheerio John On 9 November 2014 10:53, Pierre Béland pierz...@yahoo.fr wrote: About the video of the Eurosha volunteers, I forgot to add the link. This is https://www.youtube.com/watch?v=saFsT558Xbo Pierre ___ HOT mailing list HOT@openstreetmap.org https://lists.openstreetmap.org/listinfo/hot ___ HOT mailing list HOT@openstreetmap.org https://lists.openstreetmap.org/listinfo/hot
