Re: [OSM-talk] Ideas for student project on OSM
I´d like the OSM equivalent the watchlist function in MediaWiki. Ideally I would be able to get an email alerting me when changes are made to areas I am interested in. On Tue, Oct 28, 2008 at 11:35 PM, Matt Amos [EMAIL PROTECTED] wrote: On Tue, Oct 28, 2008 at 8:24 PM, Freek [EMAIL PROTECTED] wrote: I have not seen those (would be interested), but I would guess rectangular queries make an equilateral-triangle subdivision inherently less favourable, even though the geometry is distorted by the projection i think it might have been this one... or maybe not... it was a long time ago :-) http://research.microsoft.com/research/pubs/view.aspx?tr_id=736 (we don't have much data near the poles anyway ;-) this is exactly why an icosahedral decomposition is so good - each tile in the same level of the tree is very nearly the same projected area. the quadtile approach (whether using 3395 or 4326) projects to much smaller areas near the poles than the equator, so wastes valuable coordinate space and unbalances the tree. if the icosahedron is oriented correctly (fuller's dymaxion orientation) then several of the triangular faces are completely filled with ocean and can be omitted. cheers, matt ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk -- Tel: +44(0) 7814 517 807 ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Ideas for student project on OSM
El Miércoles, 29 de Octubre de 2008, paul youlten escribió: I´d like the OSM equivalent the watchlist function in MediaWiki. Ideally I would be able to get an email alerting me when changes are made to areas I am interested in. Already done. Have a look at itoworld.com/product/osm , define an area, subscribe to the daily RSS feed for edit sessions. -- -- Iván Sánchez Ortega [EMAIL PROTECTED] Mama,mama,... porque a papa le llaman el caracol? signature.asc Description: This is a digitally signed message part. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Ideas for student project on OSM
James Stewart wrote: Sent: 28 October 2008 2:38 PM To: talk@openstreetmap.org Subject: [OSM-talk] Ideas for student project on OSM Hi, I am a contributor to the map,but also work in the University in Edinburgh. I have been talking to the people who run the MSc in GIS, they have 140 students, and have to propose potential dissertation projects. Most of the students work on the technology side, programming and developing tools. Has any one got any ideas of the sorts of work that could be done/needs to be done for the OSM project that a post grad student could work? I'd suggest you get students to read up about the project and get enthusiastic for something. They will be much more productive if they come up with an idea themselves, true OSM style. Cheers Andy ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Ideas for student project on OSM
Andy, Unfortunately it will be too late then. We h ave to seed them with ideas, which they choose fairly soon, in order to start next year, so we are looking for examples of projects to get them interested, rather than hope they get interested first, James On 28 Oct 2008, at 14:54, Andy Robinson (blackadder-lists) wrote: James Stewart wrote: Sent: 28 October 2008 2:38 PM To: talk@openstreetmap.org Subject: [OSM-talk] Ideas for student project on OSM Hi, I am a contributor to the map,but also work in the University in Edinburgh. I have been talking to the people who run the MSc in GIS, they have 140 students, and have to propose potential dissertation projects. Most of the students work on the technology side, programming and developing tools. Has any one got any ideas of the sorts of work that could be done/needs to be done for the OSM project that a post grad student could work? I'd suggest you get students to read up about the project and get enthusiastic for something. They will be much more productive if they come up with an idea themselves, true OSM style. Cheers Andy -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Ideas for student project on OSM
Do you know this: http://wiki.openstreetmap.org/index.php/Student_projects and related pages on the wiki ? Pieren On Tue, Oct 28, 2008 at 3:59 PM, James Stewart ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Ideas for student project on OSM
On Tue, Oct 28, 2008 at 02:38:05PM +, James Stewart wrote: Hi, I am a contributor to the map,but also work in the University in Edinburgh. I have been talking to the people who run the MSc in GIS, they have 140 students, and have to propose potential dissertation projects. Most of the students work on the technology side, programming and developing tools. Has any one got any ideas of the sorts of work that could be done/needs to be done for the OSM project that a post grad student could work? Just a few random ideas: - generate places tree (i.e. Continent - Country - State - District - City etc.) - Bonus: house numbering - layering: use several OSM API instances to store (different types of) data (e.g. main API + phone numbers/contact information) - add layering support to JOSM - CLI tool for accumulating information from different API instances - CLI tool for splitting and feeding information into different API instances - relation editing: - add modular / easily extensible special purpose relation editors to JOSM - Turn restrictions - Bus routes - Collected ways - ... CU Sascha -- http://sascha.silbe.org/ http://www.infra-silbe.de/ signature.asc Description: Digital signature ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Ideas for student project on OSM
I suggest the region-based history idea. The source for it's data will be a planet file plus all the subsequent diffs. It must then be able to get the map for any given historic time and any reasonable bounding box. The challenge is to index all that data and provide a reasonable service to the community. Optionally it should be able answer the query when a particular bounding box was changed. Some more info here : http://wiki.openstreetmap.org/index.php/Talk:OSM_Protocol_Version_0.6 ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Ideas for student project on OSM
El Martes, 28 de Octubre de 2008, James Stewart escribió: Has any one got any ideas of the sorts of work that could be done/needs to be done for the OSM project that a post grad student could work? Right off the top of my head, on the it would be useful section: - OSM - to - WFS-T bridge (or read-only live WFS interface) - Support for more map projections in JOSM - Support for georeferenced raster images in JOSM (jpg would do; jpeg2000 and ecw would be a plus) - Support for OSM API 0.6 in traditional GIS software (arcgis, qgis, grass, gvsig, whatever) - A method for getting submetric GPX traces based on raw data from garmin receivers (build on top of the GPS post-processing stuff at http://artico.lma.fi.upm.es/numerico/miembros/antonio/async/ ) - Tool to automatically detect large sections of overlapping area ways (i.e. administrative borders shared between administrative areas), and convert the area ways into relations (heavy graph theory here) Also, on the good to know section: - PostGIS vs. MySQL spatial vs. Oracle Spatial vs. MS SQL server benchmarks. SQLite anyone? - R-tree vs. quadtiles benchmarks. Also, on the less useful but awesome anyway because OSM has so much cool data section: - Render the OSM dataset in a cool and useful projection, such as sinusoidal or an Icosahedral Pseudoglobe (that last one would be a nice swag item for the State of the Map). - Benchmark a quadtile solution vs. a more general geodetic grid tree solution (get the quadtile idea, apply it to triangles instead of squares, put 'em on a geodesic sphere; basically, instead if dividing a square into four squares, you increase the chord factor of a fractal geodesic sphere by one). Throw in a R-tree benchmark for good measure. Cheers, -- -- Iván Sánchez Ortega [EMAIL PROTECTED] Now listening to: Broadway Project - In Finite (2005) - [2] I, Partisan (4:48) (0.00%) signature.asc Description: This is a digitally signed message part. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Ideas for student project on OSM
On 28 Oct 2008, at 15:33, Iván Sánchez Ortega wrote: El Martes, 28 de Octubre de 2008, James Stewart escribió: [..] - Support for more map projections in JOSM Could also add it to Merkaartor. [...] Also, on the good to know section: - PostGIS vs. MySQL spatial vs. Oracle Spatial vs. MS SQL server benchmarks. SQLite anyone? There has already been some testing of osm data in SQLite, and there it is only suitable for small (less than 2GB) amounts of data. Shaun smime.p7s Description: S/MIME cryptographic signature ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Ideas for student project on OSM
Write a tile data server: http://wiki.openstreetmap.org/index.php/Tile_data_server ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Ideas for student project on OSM
El Martes, 28 de Octubre de 2008, Iván Sánchez Ortega escribió: - Benchmark a quadtile solution vs. a more general geodetic grid tree solution (get the quadtile idea, apply it to triangles instead of squares, put 'em on a geodesic sphere; basically, instead if dividing a square into four squares, you increase the chord factor of a fractal geodesic sphere by one). Throw in a R-tree benchmark for good measure. Related to this... Create a way to render triangular tiles matching such a fractal geodesic index... and... Modify KDE's Marble in order to render a geodesic sphere :-D Cheers, -- -- Iván Sánchez Ortega [EMAIL PROTECTED] Now listening to: Gene Harris - Jazz in the City - A Beautiful Day in the Big Apple With Gare Du Nord - [9] Listen Here (4:54) (0.00%) signature.asc Description: This is a digitally signed message part. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Ideas for student project on OSM
On Tue, Oct 28, 2008 at 6:01 PM, Iván Sánchez Ortega [EMAIL PROTECTED] wrote: El Martes, 28 de Octubre de 2008, Iván Sánchez Ortega escribió: - Benchmark a quadtile solution vs. a more general geodetic grid tree solution (get the quadtile idea, apply it to triangles instead of squares, put 'em on a geodesic sphere; basically, instead if dividing a square into four squares, you increase the chord factor of a fractal geodesic sphere by one). Throw in a R-tree benchmark for good measure. e.g: http://www.cs.umd.edu/~hjs/pubs/leesdh98short.pdf there were some published benchmarks of icosahedral quadtiles vs. rectangular quadtiles vs. R(*?)-trees and rectangular quadtiles won for those benchmark conditions. i can't find the paper now, though. this was one of the reasons i never finished my icosahedral OSM server implementation. (the other one was that i spent all my time reading papers, not actually writing code...) Related to this... Create a way to render triangular tiles matching such a fractal geodesic index... and... Modify KDE's Marble in order to render a geodesic sphere :-D in 3D *and* in fuller's dymaxion projection :-) cheers, matt ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Ideas for student project on OSM
On Tuesday 28 October 2008, Iván Sánchez Ortega wrote: - Benchmark a quadtile solution vs. a more general geodetic grid tree solution (get the quadtile idea, apply it to triangles instead of squares, put 'em on a geodesic sphere; basically, instead if dividing a square into four squares, you increase the chord factor of a fractal geodesic sphere by one). Throw in a R-tree benchmark for good measure. If you want to minimize the number of disk seeks in a quadtile-like approach, using a special type of space-filling curve can also help [1]. It may be interesting to see if such an optimization criterion leads to different space-filling curves for triangle-based subdivisions. By the way, on the side of R-trees (special) space-filling curves can also be used to improve query efficiency, see the recent thread on dev [2]. A comparison with a standard type R-tree would not be fair in my opinion. On Tuesday 28 October 2008, Matt Amos wrote: there were some published benchmarks of icosahedral quadtiles vs. rectangular quadtiles vs. R(*?)-trees and rectangular quadtiles won for those benchmark conditions. i can't find the paper now, though. this was one of the reasons i never finished my icosahedral OSM server implementation. (the other one was that i spent all my time reading papers, not actually writing code...) I have not seen those (would be interested), but I would guess rectangular queries make an equilateral-triangle subdivision inherently less favourable, even though the geometry is distorted by the projection (we don't have much data near the poles anyway ;-) [1] http://dx.doi.org/10.1016/S0304-3975(96)00259-9 (sciencedirect.com, no open access. The z-curve in Fig. 2 is basically the one used in current quadtile implementations.) [2] http://lists.openstreetmap.org/pipermail/dev/2008-October/012185.html -- Freek ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Ideas for student project on OSM
Well, I'm really pleased with the performance of the fixed tile size algorithms I implemented in gosmore. OSM data is remarkably flat : Either a tile is empty (sea / rural / unmapped) or has approximately the same number of objects as any other urban tile. So if the tiles are small enough you don't need a second index (e.g. subdividing the tiles). * Arrange the tiles in a 2-D Hilbert curve to reduce disk seeks * Use integers, because most of the operations are compares On Tue, Oct 28, 2008 at 10:24 PM, Freek [EMAIL PROTECTED] wrote: On Tuesday 28 October 2008, Iván Sánchez Ortega wrote: - Benchmark a quadtile solution vs. a more general geodetic grid tree solution (get the quadtile idea, apply it to triangles instead of squares, put 'em on a geodesic sphere; basically, instead if dividing a square into four squares, you increase the chord factor of a fractal geodesic sphere by one). Throw in a R-tree benchmark for good measure. If you want to minimize the number of disk seeks in a quadtile-like approach, using a special type of space-filling curve can also help [1]. It may be interesting to see if such an optimization criterion leads to different space-filling curves for triangle-based subdivisions. By the way, on the side of R-trees (special) space-filling curves can also be used to improve query efficiency, see the recent thread on dev [2]. A comparison with a standard type R-tree would not be fair in my opinion. On Tuesday 28 October 2008, Matt Amos wrote: there were some published benchmarks of icosahedral quadtiles vs. rectangular quadtiles vs. R(*?)-trees and rectangular quadtiles won for those benchmark conditions. i can't find the paper now, though. this was one of the reasons i never finished my icosahedral OSM server implementation. (the other one was that i spent all my time reading papers, not actually writing code...) I have not seen those (would be interested), but I would guess rectangular queries make an equilateral-triangle subdivision inherently less favourable, even though the geometry is distorted by the projection (we don't have much data near the poles anyway ;-) [1] http://dx.doi.org/10.1016/S0304-3975(96)00259-9http://dx.doi.org/10.1016/S0304-3975%2896%2900259-9( sciencedirect.com, no open access. The z-curve in Fig. 2 is basically the one used in current quadtile implementations.) [2] http://lists.openstreetmap.org/pipermail/dev/2008-October/012185.html -- Freek ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Ideas for student project on OSM
On Tuesday 28 October 2008, Nic Roets wrote: Well, I'm really pleased with the performance of the fixed tile size algorithms I implemented in gosmore. OSM data is remarkably flat : Either a tile is empty (sea / rural / unmapped) or has approximately the same number of objects as any other urban tile. So if the tiles are small enough you don't need a second index (e.g. subdividing the tiles). Interesting observation... * Arrange the tiles in a 2-D Hilbert curve to reduce disk seeks Still, I think the idea of Asano et al. [1] applies because you are retrieving a set of square tiles within a rectangular query region (with a reasonable aspect ratio), but I don't know if it's really noticeably better in practice. [1] Publicly available version: ftp://ftp.inf.ethz.ch/doc/papers/ti/grpw/SFC.ps.gz -- Freek ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Ideas for student project on OSM
On Tue, Oct 28, 2008 at 8:24 PM, Freek [EMAIL PROTECTED] wrote: I have not seen those (would be interested), but I would guess rectangular queries make an equilateral-triangle subdivision inherently less favourable, even though the geometry is distorted by the projection i think it might have been this one... or maybe not... it was a long time ago :-) http://research.microsoft.com/research/pubs/view.aspx?tr_id=736 (we don't have much data near the poles anyway ;-) this is exactly why an icosahedral decomposition is so good - each tile in the same level of the tree is very nearly the same projected area. the quadtile approach (whether using 3395 or 4326) projects to much smaller areas near the poles than the equator, so wastes valuable coordinate space and unbalances the tree. if the icosahedron is oriented correctly (fuller's dymaxion orientation) then several of the triangular faces are completely filled with ocean and can be omitted. cheers, matt ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
