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Burası değişti

Posted by mehmet şanlı on 23 April 2016 in Turkish (Türkçe)

Sahilde dolguyaılarak büyük maltepe sahil park yapıldı Turgut Özal Blv. No:129 İdealtepe 34841 Maltepe/İstanbul Türkiye

https://drive.google.com/open?id=0B1NPHkrwgWZtYS02Rm1KMXVCTUU

Location: Zümrütevler, Maltepe, İstanbul, Marmara Bölgesi, Türkiye

Informe de la práctica de BIOLOGÍA realizada el día 15 de Abril de 2016.

Posted by inventadero on 23 April 2016 in Spanish (Español)

#Informe de la práctica realizada el día 15 de Abril de 2016.

##Recolección de muestras de Plancton en las cercanías del IPFPMP de Arrecife

APPS:

1.Geo Tracker - GPS tracker

2.OruxMaps

Ver en MOODLE

Location: Arrecife Centro, Arrecife, Las Palmas, Canarias, España

Travel Pulau Seribu

Posted by kepulauan seribu on 23 April 2016 in Indonesian (Bahasa Indonesia)

Kepulauan Seribu yang merupakan salah satu tujuan wisata di Jakarta ternyata menyimpan kekayaan bawah laut yang luar biasa. Pulau Seribu merupakan salah satu tempat wisata terindah yang dimiliki Indonesia. Sebut saja diantaranya pulau putri, pulau bidadari, pulau tidung, pulau kotok, pulau ayer, pulau sepa, pulau pantara dan lain-lain. Panorama alam, keindahan bawah air serta rekreasi pantai terbaik menjadi sesuatu yang ditawarkan untuk kita nikmati. Anda juga bisa menikmati berbagai macam aneka kegiatan bermain di pantai dan laut seperti diving, snorkeling, memancing, sepeda pantai, banana boat, jet ski, dan canoe.

Pulau seribu memiliki pulau resort dan penduduk, Pulau Seribu jakarta Kepulauan Seribu yang terdiri dari beberapa pulau memiliki keindahan alam bawah laut dengan pasir putihnya, Laut yang biru memiliki keindahan daya tarik para wisatawan asing dan lokal. Pulau Seribu mempunyai beberapa fasilitas water sport dan juga memiliki alat Snorkeling dan Diving sehingga wisatawan dapat menikmati keindahan alam bawah lautnya seperti trumbu karang dan hewan-hewan laut yang ada di Kepulauan Seribu. Ada beberapa Pulau Seribu yang sering di datangi oleh wisatawan asing maupun lokal, yaitu : Pulau Ayer, Pulau Bidadari, Pulau Sepa, Pulau Putri, Pulau Pantara, Pulau Pelangi,Pulau Pramuka, Pulau Tidung, Pulau Kotok, Pulau Macan.

Pulau Seribu sering sekali di adakan Event suatu Perusahaan untuk liburan, meeting dan Motivasi karyawan Perusahaan tersebut,Paket event yang sering di lakukan di pulau seribu seperti :

Paket Meeting | Paket Outing | Paket Outbound| Paket Family Gathering.

PT. WIJAYATAMA INDONESIA WISATA

JL. Condet Raya No.1 Cililitan, Kramat Jati Jakarta Timur, DKI Jakarta, 13460

CS Wijayatama : (021) 8088-9688 | 8088 0526

Hotline 24 Hours : +628159977449

Fax : 021 8088 9671

Email : pulauseribu@wijayatama.co.id

website : http://kepulauan-seribu.com

Location: Condet Raya, RT 06, RW 02, Balekambang, Kramat Jati, Jakarta Timur, Daerah Khusus Ibukota Jakarta, 13530, Indonesia

Fermate SAF Udine/3

Posted by Gabriele Dri on 22 April 2016 in Italian (Italiano)

Mappato quasi tutte le fermate della zona nord-ovest in base alle foto e alle coordinate che ho preso in questi giorni. Le riconoscerai dal formato corto con i tag name, alt_name e ref.

Cancellato tutte le fermate che avevo prematuramente inserito.

Ho solo un piccolo problema: a causa di parecchia vegetazione e abitazioni, qualche fermata nella zona del Villaggio del Sole è fuori posizione (5-20 metri ad occhio): cosa mi consigli a questo punto, riprendere le coordinate in un secondo momento oppure un posizionamento manuale "ad occhio" migliore?

Ayuda mapear pueblos pequeños Zona Cero Terremoto Ecuador / Help to Map small towns at Ground Zero Ecuador Earthquake

Posted by jose_ecu on 22 April 2016 in English (English)

Estimados amigos:

Desafortunadamente no existe un plano detallado de la ubicación de poblados pequeños, ni de carreteras o caminos en la zona del terremoto en Ecuador.

La ayuda la estan recibiendo de personas de otras ciudades del pais y del extranjero, pero ni lo nacionales conocemos la ubicacion de los pueblos pequeños que piden ayuda.

Actualmente estoy ubicando los pueblos pequeños para ayudar a orientarse a las personas que trabajan en la zona cero.

Por favor si pueden ayudarme comunicarse conmigo. Gracias

jose_ecu


Dear Friends:

Unfortunately, there is no detailed plan of small town locations or roads in the earthquake zone in Ecuador.

They are receiving the help of people from other cities in the country and abroad, but neither national know the location of the small towns who ask for help.

Currently I am placing small towns to help orient people working at ground zero.

Please if you can help contact me. Thank you

jose_ecu

Location: Sauces 4, Guayaquil, Guayas, Ecuador

Belgische Mapper van de Maand: Stijn Rombauts

Posted by escada on 22 April 2016 in English (English)

Wie ben je ?

Stijn Rombauts is 37 jaar, bio-ingenieur van opleiding en werkt bij de Vlaamse Milieumaatschappij, waar hij computermodellen van waterlopen bouwt en onderhoudt, die gebruikt worden in overstromingsvoorspellers of bij het ontwerp van wachtbekkens of vistrappen e.d. Omdat hij voor z’n werk meestal achter de computer zit, probeert hij in z’n vrije tijd zoveel mogelijk actief buiten in de natuur te zijn: te voet, met de mountainbike of in de kano.

Stijn Rombauts

Wanneer en op welke manier leerde je OpenStreetMap kennen ?

Vooral als mountainbiker ben ik altijd op zoek naar de interessantere onverharde paden en wegen en ik geraakte op den duur teleurgesteld in de (gedateerde) kaarten van het NGI. Veldwegen en bospaden hebben nogal te nijging te verdwijnen, ergens anders terug te verschijnen of te verharden. En zo ben ik ergens in de herfst van 2012 op OpenStreetMap gebotst: een kaart die op dat vlak vaak nog wel een pak slechter was en is, maar waar ik tenminste zelf kan aan bijdragen.

Gebruik je OpenStreetMap ook zelf ?

Eigenlijk gebruik ik OpenStreetMap weinig. Ik heb wel een OpenStreetMap-kaart op m’n GPS staan, maar da’s dan eerder om tijdens mijn tochten te controleren of dat paadje hier links al in OSM zit. En ik moet toegeven dat ik meestal nog eerder naar Google Maps en Streetview grijp.

Hoe map je ?

In den beginne lag mijn focus dus op de veldwegen en bospaden. Na een tijdje ben ik ook wandel- en mountainbikeroutes beginnen toevoegen. Maar gaandeweg werd het me duidelijk dat andere aspecten wel wat verfijning konden gebruiken. Zo zijn de meeste wegen gemapt toen de eerste luchtfoto’s beschikbaar zijn geworden (vermoed ik). Maar veel van die wegen liggen niet helemaal op de juiste plaats. En er zijn wegen bijgekomen, kruispunten heraangelegd, fietspaden aangelegd e.d. Daarom heb ik me al vele avonden geamuseerd met het controleren van elk wegsegmentje, niet alleen qua ligging maar ook qua tags. Het noorden van Limburg heb ik zo al eens doorploegd; momenteel ben ik even overgeschakeld naar Vlaams-Brabant. En en passant bekijk ik dan ook de foutmeldingen in Osmose en Keepright. En soms word ik afgeleid door spoorwegen of dan weer door een stukje landgebruik of nog iets anders. M’n actieradius is eigenlijk nog behoorlijk klein: Limburg, Vlaams-Brabant, Luik en Luxemburg, op een uitzonderlijke zijsprong naar Frankrijk of Noorwegen na.

Waar ben jij als mapper het meest trots op?

Het zijn allemaal maar kleine bouwsteentjes die ik links en rechts toevoeg aan het al imposante OSM-kasteel. Maar ondertussen heb ik blijkbaar toch al bijna 300 wandelroutes toegevoegd of gecontroleerd.

Stijn's Achivements Stijn's Achivements

Waarom map je ? Wat motiveert je ?

Ik ben altijd al licht autistisch geïnteresseerd of gefascineerd geweest door kaarten. En nu mag ik zelf echte kaarten tekenen! Wat meer zou ik nog kunnen wensen? ;-) Soms ben ik ook wel eventjes beu, maar dat duurt nooit lang.

Doe je ook nog andere dingen ivm OpenStreetMap ?

Misschien te weinig. Ik heb al vaak gedacht dat ik wat meer tijd in de wiki zou moeten steken. In de talk-be mailinglijst passeert heel wat interessante informatie, maar uiteindelijk is dat een redelijk vluchtig en onoverzichtelijk medium. Zeker voor nieuwe mappers gaat er zo veel informatie verloren.

Heb je ideeën over hoe we de OpenStreetMap gemeenschap kunnen uitbreiden?

De moeilijkste vraag, zeker? Ik volg het niet allemaal op de voet, maar misschien dat via contacten met organisaties als Trage Wegen de bekendheid van en interesse in OSM het snelst kan groeien.

Wat is de grootste sterkte van OpenStreetMap volgens jou?

Dat mappers van over de hele wereld kunnen meewerken aan het maken van kaarten aan de andere kant van de wereld en dan vooral voor landen of regio’s waar er geen degelijke kaarten bestaat, lijkt mij de grootste sterkte. Vele kleintjes maken een groot.

Wat is de grootste uitdaging/moeilijkheid voor OpenStreetMap ?

In België is al heel veel al wel een keer gemapt. De grote uitdaging de komende jaren lijkt mij: hoe houden we alles up-to-date? Dat ergens een stuk landgebruik ontbreekt, is gemakkelijk te zien. Dat ergens een stuk landgebruik al 5 jaar niet meer is nagekeken, is een pak lastiger te zien. Hetzelfde voor wegen, wandel-, fiets en busroutes en alle andere zaken die in OSM zitten.

Hoe blijf je op de hoogte van nieuwtjes ivm OpenStreetMap ? …

Eigenlijk alleen via de talk-be mailinglist. Wat natuurlijk maakt dat mijn venster op de ruimere, internationale OSM-wereld behoorlijk klein is.

Heb je contact met andere mappers ?

Ik ben al ‘ns keertje naar een meetup in Leuven en Antwerpen geweest, maar tja, vanuit het verre Limburg...

Om af te sluiten, is er iets dat je de lezer nog zou willen meedelen ?

Verdorie, zo’n lange vragenlijst. Weer een avond dat ik niet heb kunnen mappen… ;-)

Belgian Mapper of the Month: Stijn Rombauts

Posted by escada on 22 April 2016 in English (English)

Stijn Rombauts is a 37 year old bio-engineer who works for the Flanders Enviroment Agency, where he builds and maintains computermodels of streams and rivers. Those models are used to predict floods and to plan of e.g. fish steps and waiting basins. Because he spends a lot of time in front of the computer for his job, he tries to be active, in the nature, during his spare time: be it on foot, with the mountain bike or in a canoe.

Stijn Rombauts

How and when did you discover OpenStreetMap ?

As a mountain biker, I am constantly on the lookout for interesting unpaved paths and roads. In the end I got disappointed in the dated maps of the NGI. Field roads and forest paths have the tendency to disappear and to reappear elsewhere or to become a paved way. This lead me to OpenStreetMap, somewhere in the autumn of 2012. A map that was often worse with respect to those unpaved roads, but at least I could improve it myself.

Do you Use OpenStreetMap ?

I rarely use OpenStreetMap. I do have an OpenStreetMap-map on my GPS, but that is used only to check the existence of the paths during one of my excursions. I have to admit that I still rely on Google Maps and StreetView most of the time.

How do yo map ?

When I just started, the focus was on field roads and forest paths. After awhile I also started to add walking and mountain bike routes. But gradually, it became clear that other aspects also needed refinement. I expect that most roads are mapped when the first aerial images became available. But most of those roads are not located correctly. And new roads have been added, crossings have been redesigned, cycleways have been created, etc. That is why I have entertained myself already during many evenings by checking each and every road segment, not only the positions, but also the tags. I worked myself through the roads in the north of the Limburg province. Right now I am doing the same in Vlaams-Brabant. During this task I also look at the errors reported by Osmose and Keepright. Sometimes I get distracted by the railways, or some land use issues or some other problems. My action area is rather small: Limburg, Vlaams-Brabant, Luik and Luxemburg, with an occasional dodge to France or Norway.

What is your biggest achievement as mapper?

I only add small building blocks in several different places to the impressive OpenStreetMap-castle. But in the meantime it seems that I have added or checked almost 300 walking routes.

Stijn's Achivements

Stijn's Achivements

Why do you map ? What motivates you ?

I always had a light autistic interest or fascination for maps. And now I am allowed to draw real maps myself ! What more can I wish ? :-) There are periods during which I loose interest, but they never last long.

Do you do other things for OpenStreetMap besides mapping ?

Maybe not enough. It is not the first time that I wonder whether I should spend more time in the wiki. A lot of interesting information passes on the Belgian mailing list, but in the end that is a fairly volatile and cluttered medium. This means that a lot of information gets lost, especially for new mappers.

Do you have ideas to extent the community ?

The most difficult question, I assume ? I am not so familiar with this topic, but maybe the interest in OpenStreetMap and its community can grow the fastest via contacts with organisations such as Trage Wegen. (which is an organisation that works around roads for non-motorized traffic).

What are the strong points of OpenStreetMap ?

I think that the main strength of OpenStreetMap is that mappers from all over the world can contribute to the creation of a map on the other side of the world, especially for countries or regions for which no decent maps exist. Many small ones make one great.

What is the biggest challenge for OpenStreetMap ?

In Belgium, we have already mapped a lot of things already once. I think that the biggest challenge for the years to come is to keep all of this up-to-date. When a piece of land use is missing, one can easily spot this. That a piece of land use has not been checked, is much harder to see. The same holds for roads; hiking, cycling and public transport routes and all other objects in OpenStreetMap.

How do you stayed informed about OpenStreetMap news ?

Actually, only through the talk-be mailing list. This is of course a limited view on the activities of the world-wide OpenStreetMap community.

Do you have contact with other mappers ?

I have visited meetups in Leuven and Antwerp, but it was a long drive from Limburg.

Anything else you want to mention ?

Damn, such a long interview. Another night I could not map ...;-)

Mapping exit numbers on US motorways

Posted by jinalfoflia on 22 April 2016 in English (English)

The data team at Mapbox has been trying out mapping missing motorway exit numbers in the US. Based on the density of Mapillary street photographs, the following 9 US states were chosen to improve:

  • California
  • Florida
  • New Jersey
  • Maryland + DC
  • Pennsylvania
  • Washington State
  • Colorado
  • Texas
  • Illinois

We used the checkautopista2 tool which made it very easy to detect exits that lack a ref tag. In summary we found most of these exits to have no official exit number and added the noref=yes tag when we could confirm it on official documents or on Mapillary photographs.

exit These are the exit numbers added by the team. The pink dots represent ref=* tags and the blue dots represnt noref=yes tags added by the team, click here to view the full map

The team has been working on this from 31 March 2016 to 14th April 2016 and reviewed more than 220 highways.

  • Number of ref=* added by team on nodes highway=motorway_junction are 63
  • Number of noref=yes added by team on nodes highway=motorway_junction are 219

This is the workflow that was used for this mapping activity. Would be great to hear your feedback on how it can be improved for further such tasks, please drop a comment here or on the project tracker.

Happy Mapping!

گناباد به کاخک

Posted by hamidreza20 on 22 April 2016 in Abkhazian (Аҧсуа)

اشکالات این قسمت و مشکل در مسیریابی برطرف شد

Location: ۴۰۰ دستگاه, گناباد, خراسان رضوی‎, جمهوری اسلامی‏ايران‎

Mapping Torre Annunziata

Posted by doktorpixel14 on 22 April 2016 in English (English)

Hey, Today I present you my work in Torre Annunziata (near Naples) of the last two months:

After I edited Before I edited

Here you see the map now, compared to the MapQuest Open map (which is not updated yet).

I created more then 10,000 objects, which include shops, addresses, buildings and streets.

Location: Rione Carceri, Torre Annunziata, NA, Campania, Italy

Running for HOT Chair of Voting Members

Posted by mikelmaron on 20 April 2016 in English (English)

I'm running for Chair of Voting Members for Humanitarian OpenStreetMap Team.

I see the Chair as a straightforward role. The key responsibility is to communicate responsibilities and opportunities to HOT Voting Members, and organize the space for official convening and processes. This includes notification of Annual and Special Meetings, Elections and Ballots, as well as ensuring announcements of other meetings, like Working Groups. Expect to work closely with the Board Secretary and HOT's Operations Coordinator, and the Governance Working Group, in these tasks.

My work over the last year with the Governance Working Group has prepared me well for this role. I have been closely studying, revising and clarifying HOT's Bylaws and processes, with focus on making our governance work well for us.

This work be done with excellent clarity. HOT Voting Members cover nearly every time zone, many languages, and everyone's time is precious. Our governance responsibilities should be straightforward and understandable, so we can focus most of our efforts on the amazing core work of HOT.

Using Maps.me mobile editor for the first time

Posted by jinalfoflia on 20 April 2016 in English (English)

Maps.me is a mobile application that provides offline map service world wide and it uses OpenStreetMap. It also provides a provision to add POIs and building information. This means more eyes and contributors to OpenStreetMap. I played around with maps.me application for Android, these are some points that we should make note of:

  • The UI is smooth and makes it easy to add POI's on map.
  • It's a really good mobile editor.
  • The app provides fields that will help the user add information about a POI/Buildings conveniently.
  • The maps are updated only with the next release of the application, so the changes made by the user on OpenStreetMap will not be reflected until the next release of the application.
  • The tags provided are limited, for example common tag like university is absent.

photo_2016-04-20_15-13-00

  • These maps are downloaded and saved offline, so the changes made are also saved locally and they get pushed automatically to OpenStreetMap once the user connects to the Internet.
    • There is no pop-up stating that the data is being uploaded to OSM
    • The app adds it's own changeset comment (the user doesn't have an option to add custom comment to the changes they make) screen shot 2016-04-20 at 12 52 06 pm

Adding a place using maps.me application

video_2016-04-20_13-52-25

Issues that are concerning:

  • Since the map is only updated with the new release of the application, there are possibilities of duplication of data.
  • One can add POIs on top of another POIs. The application doesn't caution users with a warning that data already exists.
  • Many POIs were found to be in the middle of the road, this is probably due to gps variations.

poornibadrinath and I came across these changesets which has the editor=maps.me, here are the observations:

screenshot 2016-04-20 12 10 00

screenshot 2016-04-20 12 20 11

screenshot 2016-04-20 12 47 21

screenshot 2016-04-20 12 51 48

Feature requests, bugs and suggestions regarding this application can be reported in their github repository.

Mijn leven...

Posted by Varkpower on 20 April 2016 in Dutch (Nederlands)

Lief dagboek

Dit is mijn leven

einde

Ik ben jij

Posted by Varkpower on 20 April 2016 in Dutch (Nederlands)

Lief dagboek,

ik ben jij

einde

Open Peer Review Process at Mapbox

Posted by pratikyadav on 20 April 2016 in English (English)

As part of the Mapbox Data team, we make sure that our contributions to OpenStreetMap from our mapping projects, through user feedback and support to HOT activations are at par with the OpenStreetMap data quality standards. One of the ways we check data quality is through our weekly manual peer review process.

To be more open towards our QA processes, we are bringing our manual peer review accessible for anyone to participate.

cwe5a3kxiaact3a

The process of manual peer review are as follows:

  • Every Wednesday a new Peer Review Ticket will be opened in our mapping repo with the following information:

    • List of projects the team worked on last week;
    • Link to each member's edits (in .osm format) extracted using osm-history-processor
    • Instructions on loading data to JOSM.
  • After loading the data for a specific team member in JOSM, we compare the edits to the latest data.

  • We use JOSM filters to see only the edits of a specific team member.

  • We review quality based on the context of the mapping project. Specifically, we look for:

  • The reviews are compiled as ticket comments for each team member providing links to changeset/ways/nodes that should be fixed.

  • Each team members will check all reported issues and correct the edit if necessary. In case of disagreements, we use changeset comments to discuss specific edits.

Aside from the manual peer review, we also run daily automated error detection with OSMLint and validation using the Tasking Manager.

We invite the community to take part in the process and improve workflow. Feel free to comment on the peer review ticket to report any quality issues in our edits.

Happy mapping.

Mapbox's probably fragmentary "Tracking conversations" tool

Posted by malenki on 19 April 2016 in English (English)

This message I wanted to send to Mapbox. Regrettably you either need to create an account to "contact" them or use some fancy social network foo.
Ever written an email on twitter?

Thus I paste the mail here and link it on twitter. Brave new world…

Hi,

in January you published a new tool named "tracking conversations"¹ which is supposed to list (I assume all) comments a user made on Notes or Changeset Discussions at OSM. Querying for changeset discussions I contributed to since January shows a meagre three discussions:
https://www.mapbox.com/osm-comments/#/changesets/?q=from:2016-01-01%20users:malenki&show=all
Pascal Neis' tool which shows only the discussions of the last seven days lists seven changeset discussions from me: http://resultmaps.neis-one.org/osm-discussions#11/51.1279/14.2215

Do I handle your tool wrong or does it have a bug?

Best regards
[malenki]

Please send an answer to osm at malenki dot ch
(It would be useful to have an "your email address"-field on the tech support form as well)

¹ https://www.mapbox.com/blog/osm-comments/

300 ....

Posted by Harald Hartmann on 19 April 2016 in German (Deutsch)

... ist die nächste Ausgabe der Wochennotiz ... ein Grund um mal zu schauen, was noch so alles hinter dieser Zahl steckt:

Hab ich was vergessen? :)

Ofis Mobilyaları

Posted by ofismob on 19 April 2016 in Turkish (Türkçe)

Ofis Mobilyalarinda lider firma Nehir Ofis Mobilyasi ile ofislerinizin trendlerini 2016 standartlarina tasiyin. En uygun fiyatli ofis mobilyasi garantisi, yaza ozel %30 indirimli buro mobilyalaiı ve 5000 m2 kapasiteli shoowromuyla nehir ofis hizmetinizde.

Sac Ekimi

Posted by mdhair on 19 April 2016 in Turkish (Türkçe)

Erkeklerin en buyuk sorunlarindan biri de Sac Dokulmesi. Sac dokulmesini engellemek mumkun degil ama dokulen saclar Dogal Sac Ekimi yöntemleriyle Md Hair Center kalitesinde mumkundur. En uygun Saç Ekimi fiyatları icin Md Saç Ekim Merkezini tercih edin.

Updating NYC building footprints - Part 1

Posted by PlaneMad on 19 April 2016 in English (English)

NYC had an import of over 1 million building footprints and 900,000 addresses in 2014 from the New York City Department of Information Technology and Telecommunications (DoITT). The DoITT GIS releases an updated shapefile of the footprints every quarter, and the latest version can be accessed here: Building footprints | Address points

Open datasets like these are a great opportunity to explore how OSM can be used as a bridge between authoritative information and that crowdsourced by citizens. Two years after the import, it is interesting to see how the OSM data compares with the latest official footprints. The interesting questions to ask is:

  • What has improved in the DoITT footprints that can be updated in OSM?
  • What has improved in OSM that can be updated in the DoITT data?

Both of these are pretty challenging questions and requires some careful data comparison and conflation. manings and I were trying our hand at answering these questions and here is our progress.

Preparing the data

Grab the latest NYC footprints from DoITT and the NYC OSM extract from Mapzen.

Use QGIS to filter only the buildings from the OSM extract and save it as a separate shapefiles to make the analysis slightly faster.

Visual diff of footprints

A simple way to quickly see a difference between the geometries in the two datasets is to do a visual diff by overlapping the layers with different colors. Geometries that don't overlap will show the color of the underlying layer.

screenshot 2016-04-14 17 34 26 Green=missing in DoITT; Yellow= OSM overlaps DoITT; Red=missing in OSM. (interactive map)

This is a purely visual comparison and with some eyeballing, we noticed not much has changed. The green buildings on the New Jersey side are outside the import area and do not exist in the DoiTT dataset. We know have a few more questions that lie unanswered:

  • Why are there missing buildings in the latest DoiTT data, is it because OSM more updated, or have the buildings been demolished and OSM is outdated?
  • Why are there missing buildings in OSM? Were they demolished and deleted, or were they never they never added in the first place?

Both the above questions can be answered if we know which dataset is more updated, and the only reliable method to find out is to visit the site and ground truth the information.

Centroid diff of footprints

Next we will try to detect changes in building configurations, where buildings might have combined or been split from its parent. This can be done by comparing the centroids of the two footprint datasets and check if they match. To do this, we can first extract the centroid of all the OSM footprints, and using a point in polygon analysis, find out how many centroid intersect with every DoITT footprint.

screenshot 2016-04-14 18 28 57 Black=0 OSM footprints at location; Grey=1 OSM footprint at location; Yellow= 2 OSM footprints at location; Red=2+ OSM footprints at location

untitled2 This method can isolate the footprints that need to be added into OSM, but its not a simple insertion as there may be cases where a single building might need to be split into smaller buildings

untitled2 This also detected overlapping polygons in OSM, and cases where multiple buildings need to be combined into larger buildings

untitled2 In cases where the buildings have transformed their shape drastically, the centroid may not overlap and get flagged as a missing building

Minor shape changes don't get flagged

Stats - Total footprints in DoITT dataset: 1,082,433 - No existing OSM footprint at location (PNTCNT=0): 1,223 footprints to add - 1 existing OSM footprint at location (PNTCNT=1): 1,072,975 footprints not changed or with minor geometry changes - 2 existing OSM footprints at location (PNTCNT=2): 1,661 footprints to be merged or updated - More than 2 existing OSM footprints at location (PNTCNT>2): 251 footprints to be merged or updated

View Map | JOSM/iD TMS https://api.mapbox.com/styles/v1/planemad/cilja03bn002bccm7chcpw604/tiles/{z}/{x}/{y}?access_token=pk.eyJ1IjoicGxhbmVtYWQiLCJhIjoiemdYSVVLRSJ9.g3lbg_eN0kztmsfIPxa9MQ

Shape diff of footprints

The above analysis can still miss out on minor shape changes. To find out which buildings were modified since the last import, we tried to compare shape changes using the nycdoitt:bin footprint id as primary reference key.

For each nycdoitt:bin polygon from OSM and NYC:

  • compute the perimeter and area.
  • get the absolute difference between both polygons.

This process confirms the centroid diffs in our test area and can further identify shape changes where, the buildings were not deleted/added but shapes were improved, etc. This is only true if the nycdoitt:bin id has not changed. However, we noticed that the building id from the NYC changes a lot and is not unique to each building. For example, in our test area, we found many duplicate entries (i.e. 1000000 = 106; 2000000 = 1482; 3000000 = 2052; 4000000 = 10119; 5000000 = 2623). Taginfo confirms this thus, using the nycdoitt:bin id is not the best approach to do this comparison.

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Clearly none of these approaches give a clear picture of how to conflate the two datasets. Our next attempt would be at using a more traditional approach using PostGIS to intersect geometries and compare the differences for a manual review. We're hoping to have a reusable workflow that can be used by open data agencies like NYC DoITT to use updates from OSM and also give back to the map more often.

Would be great to hear about alternate approaches for data conflation and strategies that could be explored in the future. You can look forward to another update on the spatial adventures of Maning and I soon.

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