Le portail francophone de la géomatique

Feeds

61038 items (0 unread) in 112 feeds

Dans la presse

• Directions Magazine : A la une
• Directions Magazine : Blogue
• SIG la lettre : à la une
• SIG la lettre : actualité
• SIG la lettre : Produits et Services
• Les Rencontres de SIG-la-Lettre
• SIG la lettre : divers
• Directions Magazine : Communiqués de presse
• BalizMedia : Communiqués de presse
• PortailSIG - Actualité
• Revue Internationale de Géomatique : Numeros de 2012
• magazine CARTO

Du côté des éditeurs

• Imagerie Géospatiale
• Virtual Earth in Europe by Arnaud
• Geospatial made in France
• GéoTrouveTout
• Humblogue
• le blog decigeo
• Articque - Les Sytèmes d'Analyse Géographique, la cartographie, le géomarketing et la géostatistique
• GeoConcept
• arcOrama, un blog sur les SIG, ceux d ESRI en particulier
• arcOpole - Actualité du Programme
• arcUtilisateurs
• Geomatys
• Blog Géoclip O3, générateur d'observatoires

Toile géomatique francophone

• Le blog TIC » Information Géographique
• Geospatial air du temps by Géo212
• Monde géonumérique
• Le petit blog cartographique - Article
• ReLucBlog - SIG, MOZILLA & NTIC
• TerrImago "Le temps du monde fini commence" (Paul Valéry)
• GeoInWeb
• Le monde de la Géomatique et des SIG ... tel que je le vois
• Géographie 2.0
• BloGoMaps - google maps france
• GeoRezo.net - Géoblogs
• Geotribu
• Benjamin Chartier
• neogeo
• OpenSource, Geospatial et Web ?.0
• Faire joujou avec son GPS
• Géomatique et Topographie
• HelioMap
• La chronique de la parallaxe
• Remote In Every Sense
• UrbaLine
• GEMTICE
• Serial Mapper
• SIG-o-Matic
• Cybergeo
• Librairie La GéoGraphie • Actualité internationale
• Les Cafés géographiques
• Une carte du monde.
• Mappemonde
• Les blogs du Diplo - Visions cartographiques
• Oslandia
• Le Forum français de l'OGC
• Inventis Géomarketing
• Blogue de la géomatique du MSP
• Blog technique de Nicolas Boonaert
• WebMapping
• A GeoSpatial World
• Cartes et Cartographie / Maps and Mapping
• Sample Digital Orthophoto Images
• Silatitudes - Accueil
• RSS Libre@vous
• Blog d'Intelli3
• Audissey
• GeoReader's Digest
• Michael TRANCHANT
• Le blog d'Henri Pornon
• Le blog de l'image satellite - CNES
• Data and GIS tips
• Geo By The Cloud
• 123 Opendata
• ReLucBlog
• L'Atelier de Cartographie
• AdrienVH.fr, le blog » Cartographie
• Cartes et figures du monde
• Baptiste Coulmont » cartographie
• l'aménagerie » SIG
• geomarketing.ca
• 
• My Geomatic
• OpenStreetMap France
• Sigea : actualités
• Sigea : Quoi de neuf
• Géoportail.fr
• Géosource
• www.touraineverte.com
• archeomatic
• Geographica » Cartographica
• Tutoriels et formations gratuits des logiciels SIG ArcGIS, MapInfo, ArcView GIS etc.
• simon mercier

Géomatique anglophone

• Planet Geospatial - http://planetgs.com
• Google Maps Mania
• All Points Blog
• Directions Media - Podcasts
• Navx
• James Fee GIS Blog
• OGC News Feed

Blogs GeoRezo.net

• Parcell'air
• Le coin de l'open-source géospatial
• INSPIRE by clouds
• Les GéoBlogs
• Infobulle
• Le blog SIG & URBA
• Blog Interopérabilité & GéoInformation

Autres planets

• Planet OSGeo

• 07 mars 2010
• 23:37

  Martin Davis: Open Source Geocoders

  sur Planet OSGeo
  One of the more interesting projects we have going on here at Refractions is to build a geocoder for use in a crime-mapping application we are developing for a client. We do have an existing geocoder codebase developed for another project. But we're not 100% happy with its performance and customizability, so we decided to look into developing a new library specifically for this project.
  
  Of course the first thing we did was carry out a technology review of all the open-source geocoders we could find. Here's a list of all the ones we looked at:
  

  • Geo-Coder-US - A Perl module developed by the ubiquitous Schuyler Erle. "For geocoding US addresses, that is, estimating the latitude and longitude of any street address or intersection in the United States, using the TIGER/Line data set". Probably no longer being developed, since it has been superseded by

  • GeoCommons Geocoder::US - a rewrite of Geo-Coder-US into Ruby (and also requiring C and SQLite). "Although it is primarily intended for use with the US Census Bureau’s free TIGER/Line dataset, it uses an abstract US address data model that can be employed with other sources of US street address range data"

  • JGeoCoder - A Java API loosely modelled after Geo::Coder::US. Works against a SQL database loaded with TIGER data (an H2 image is supplied). Last activity in 2008.

  • Explorer GeoCoder by SRC - A C++ library for "a data and country independent geocoding engine" which can "assign latitude and longitude coordinates to any United States street address or intersection". Has an active mailing list.

  • Frost Tiger Geocoder by Stephen Frost et al - a Postgres SQL library for geocoding against TIGER data
    

  (This is summarized in tabular form on this Tsusiat page).
  
  Some observations:
  

  • All of the engines implement parsing and matching logic purely in code. None of them provide a declarative description language to allow easy modification of parsing, standardization, and matching rules. (To be fair, this is bit of a tall order. And it's not clear that it's even possible to provide an understandable declarative language for the fully general case. For example, the ArcMap geocoder (which appears to be the old MatchWare engine) provides a geocoding definition language (actually 5 different ones) - but the languages look scarily complex! Nonetheless, this is an important feature for easy of maintenance and customization.)
  • JGeoCoder uses a large number of complex regular expressions to perform parsing. This looks like it would be difficult to customize, due to the well-known opaqueness of large REs, and perhaps also to the relative inflexibility of the RE paradigm
  • The GeoCoder::US Ruby module seems to be the simplest code base. (I ended up almost understanding its parsing algorithm 8^) It uses REs, but in a saner amount. However, it's unclear how well it deals with erroneous input data, and how easy it would be to modify for a different address model.
  • The Explorer geocoder uses a large amount of fairly complex C++ code. It also looked quite challenging to understand and modify.
  • In all the projects the parser design appears to be fairly ad-hoc and poorly documented. This situation doesn't inspire confidence that it would be possible to modify the parser to support a different address model, or to handle particular kinds of input errors. (GeoCoder::US is a possible exception to this - it has a relatively simple parsing algorithm with at least some documentation).
    

  In the end we decided not to use any of these projects. I'll talk about what we did do in another post.

• 23:31

  Slate Wants Hand-Drawn MapsThe Map Room

  sur Planet Geospatial - http://planetgs.com
  Slate's Julia Turner is the latest to put out a call for hand-drawn maps, in a post that is part of her series on signs: The maps we draw for one another also have a certain ephemeral beauty. Each map is the product of a conversation. While most professional maps...
• 23:26

  Bernard GutsellThe Map Room

  sur Planet Geospatial - http://planetgs.com
  Via MapHist, news of the passing on Thursday of Bernard V. Gutsell (1914-2010), who founded the journal Cartographica in 1965....
• 23:19

  Positional Accuracy Part 2The ENTCHEV GIS Blog

  sur Planet Geospatial - http://planetgs.com

  So how do you define accuracy? In the GIS world there are a few different types of accuracy to consider. When some people hear the word “accuracy” they think about the bullseye on a dart board and how close someone can stick the dart near that bullseye. Since spring training just started others may think about a baseball pitcher and how close he can get the ball to the catcher’s mitt or strike zone. As a GPS/GIS person I usually define accuracy as how close the GIS feature is to its true location on the planet, with separate accuracy values for horizontal and vertical location. But accuracy can be defined a few ways in a GIS.

  First a few questions; what is the true location of a feature and how can someone find the true location of a feature to tell how accurate their data is? (To be answered later) The second question; does the true location really matter? I have found over the many years I have been working with GIS data that people often don’t want “accurate” data, they want data that looks good. By looking good I mean that the data agrees with the base mapping that is currently being used. So even if the base map is of poor quality as long as the other data overlays nicely everything else doesn’t matter.

  That leads me to my multiple definitions of accuracy. In the GIS world we have what I often refer to as “absolute accuracy”, which I use to describe how close a feature is to its true location, as defined by the geodetic datum and adjustment being used. And then we have what I describe as “relative accuracy”, which I use to describe how close to the true distance one feature is relative to another shown on the same map. In this part of the country most land surveys are still done with relative accuracy as the only consideration and I find in the GIS world that digitizing is still very popular because of the relative accuracy visual benefits.

  In the early stages of GIS development the difference between relative and absolute accuracy were a big issue. People were trying to use poor quality base maps that sometimes had no real-world coordinates at all. Since then base map quality has improved tremendously. Good thing because as more people wanted to use GPS to add data to their GIS absolute accuracy became very important. Even still I find that the base map and relative accuracy to the base map is the most important concern when displaying data to people that don’t understand accuracy issues.

  In my area of the U.S most people are now using orthophotos as their base map. But if I go out and locate the position of a well defined feature using survey-grade GPS techniques and I establish the “absolute accuracy” of that feature to +/-1cm but that location doesn’t overlay onto the base map nicely I find that people want to believe the base map before the feature location. It seems hard for people to understand the idea that everything we look at on a map has an error associated with it and that it's ok for a +/-1cm point to be "off" 80cm when the base map itself is +/-1m. Some features may have more error or lower accuracy than others, even the base map itself.

  It seems that relative accuracy to a base map is still most important when viewing the data but absolute accuracy becomes more important when the GIS matures and people want to start uploading the GIS data back onto ever more sophisticated GPS equipment and portable computers for maintenance and/or feature recovery, especially is the feature is buried or difficult to find. The bottom line, use the most accurate base map available, if possible include estimated accuracy values in all databases, make sure all datum references are properly identified, and if you need to “adjust” feature locations to make the data overlay onto a base map better please make a copy of that layer before editing if the original layer has a higher absolute accuracy than the base map.         

   

  Next Post: Where do GIS and GPS positional errors come from?

• 20:34

  Apocalpyse Cow ? (2) Les vaches aménagent le territoire

  sur Les Cafés géographiques
  Il y a bien longtemps, c'était dans le dernier quart du XIXe siècle, lorsque les Etats-Unis se lancèrent dans le commerce mondial des grains, le prix des céréales s'effondrait en France et dans de nombreuses régions de polyculture. On vit les vaches venir au secours des hommes. L'Auxois, au pied du Morvan, devint la terre d'élection d'une race locale, le charolais, qui allait assurer sa prospérité. Et dans bien d'autres régions, ce fut le même sauvetage.
  Aujourd'hui, c'est « Haro sur le bovin ! » Même (...)
• 20:34

  Apocalypse Cow ? (2) Les vaches aménagent le territoire

  sur Les Cafés géographiques
  Il y a bien longtemps, c'était dans le dernier quart du XIXe siècle, lorsque les Etats-Unis se lancèrent dans le commerce mondial des grains, le prix des céréales s'effondrait en France et dans de nombreuses régions de polyculture. On vit les vaches venir au secours des hommes. L'Auxois, au pied du Morvan, devint la terre d'élection d'une race locale, le charolais, qui allait assurer sa prospérité et la sauver du naufrage. Et dans bien d'autres régions, ce fut le même sauvetage.
  Aujourd'hui, c'est « Haro sur (...)
• 20:34

  Apocalypse Cow ? (2) Les vaches aménagent-elle encore le territoire ?

  sur Les Cafés géographiques
  A l'occasion du Salon de l'agriculture. Voir aussi Apocalypse Cow ? (1)
  Il y a bien longtemps, c'était dans le dernier quart du XIXe siècle, lorsque les Etats-Unis se lancèrent dans le commerce mondial des grains, le prix des céréales s'effondrait en France et dans de nombreuses régions de polyculture. On vit les vaches venir au secours des hommes. L'Auxois, au pied du Morvan, devint la terre d'élection d'une race locale, le charolais, qui allait assurer sa prospérité et la sauver du naufrage. Et dans bien (...)

• 20:27

  Gay Bars and Clubs on Google Maps

  sur Google Maps Mania
  GayBarMapsThe GayBarMaps website provides up-to-date information about gay bars, clubs, taverns, pubs and nightclubs. The site uses Google Maps to show the locations of all the bars in its database.The map for each location allows the user to select from a number of categories, Bars, Restaurants, Lodging, Events and Other. Clicking on a map marker reveals the name and address of the bar and a

• 20:00

  Parcours et identité des migrants

  sur Les Cafés géographiques
  Débat, "Parcours et identité des migrants", le mercredi 7 mars de 20h à 22h, au café Le Flesselles, organisé par l'association d'étudiants géographes nantais Geode et l'institut de géographie de l'Université de Nantes avec Mickaël Garreau, responsable Pays de la Loire de la Cimade, association de solidarité avec les migrants et Mehdi Alioua, sociologue à l'Université de Toulouse Le Mirail, spécialiste de la migration (...)
• 20:00

  Parcours et identités des migrants

  sur Les Cafés géographiques
  Débat, "Parcours et identité des migrants", le mercredi 7 mars de 20h à 22h, au café Le Flesselles, organisé par l'association d'étudiants géographes nantais Geode et l'institut de géographie de l'Université de Nantes avec Mickaël Garreau, responsable Pays de la Loire de la Cimade, association de solidarité avec les migrants et Mehdi Alioua, sociologue à l'Université de Toulouse Le Mirail, spécialiste de la migration (...)

• 18:05

  The Library as Digital Creation Center and Urban Informatics ProcessorSpatial Sustain

  sur Planet Geospatial - http://planetgs.com
  The new digital resource center at the State Library of Queensland envisions the future library as a place for creativity for, “art, design, gaming, engineering, sound, science, craft and architecture.” The idea of the new facility called the Edge is to foster connections for multidisciplinary design work and to foster innovation. The $7.9 million construction [...]
• 17:32

  In Praise of InnovationSpatial Sustain

  sur Planet Geospatial - http://planetgs.com
  I’m a fan of Thomas Friedman’s mix of doomsaying and praise of innovation. He’s a great cheerleader of the American drive to be the best in the world through innovation. In his column today he outlines two innovators in the green technology space. There’s a truly exciting process that could make coal fired powerplants much [...]

• 16:50

  GeoJQuery

  sur Benjamin Chartier

  Un nouveau projet est en train de prendre forme : GeoJQuery (cf. ici et là). Une liste de diffusion de l’OSGeo consacrée à ce projet vient également d’être créée (cf. ici).

  L’objectif du projet : faire quelque chose de similaire à GeoExt mais sur la base de jQuery au lieu de Ext JS.

• 16:31

  Laser Scanning the Hold of a Whaling ShipLiDAR News

  sur Planet Geospatial - http://planetgs.com

  A well done presentation for the boat lovers and those not familiar with laser scanning.

  Click here to view the embedded video.

• 16:05

  N°1. Vidal de la Blache. Cabris. Préalpes de Grasse.

  sur Les Cafés géographiques
  Ce dessin est tiré du carnet n° 26 (1907, p.53) de Paul Vidal de La Blache, retrouvé avec les autres dans les archives de l'Institut de Paris par Bernadette Joseph et identifié par Marie-Claire Robic. Vidal a couvert ainsi 33 carnets qui concerne plus d'une vingtaine de pays, à commencer par la France qu'il a largement parcourue lors de la préparation du Tableau de la géographie de la France, tome 1 de l'Histoire de France d'Ernest Lavisse. Les textes en ont été transcrits et étudiés par l'équipe « Histoire et (...)
• 16:05

  N°1. Vidal de la Blache. Cabris. Préalpes de Grasse

  sur Les Cafés géographiques
  Ce dessin est tiré du carnet n° 26 (1907, p.53) de Paul Vidal de La Blache, retrouvé avec les autres dans les archives de l'Institut de Paris par Bernadette Joseph et identifié par Marie-Claire Robic. Vidal a couvert ainsi 33 carnets qui concerne plus d'une vingtaine de pays, à commencer par la France qu'il a largement parcourue lors de la préparation du Tableau de la géographie de la France, tome 1 de l'Histoire de France d'Ernest Lavisse. Les textes en ont été transcrits et étudiés par l'équipe « Histoire et (...)

• 15:38

  Nine States and Washington DC Receive FGDC "50 States" CAP GrantsNSGIC News

  sur Planet Geospatial - http://planetgs.com
  Nine states and the District of Columbia have been awarded grants for strategic and business planning under the 2010 CAP Grant program from the Federal Geographic Data Committee (FGDC). The awards are under two categories from the 2010 CAP Grant program that are focused on the 50 States Initiative: Category 3 (Strategic and Business Plan Development) and Category 4 (Business Plan Development and Implementation).
  
  
  
  Category 3 Recipients
  
  

  • With strong political support from their Governor, the Alabama GIS community is ready to use a Strategic Plan to move forward.
  • GIS professionals in Alaska note that their state is less well-mapped than the Moon. They will use their grant to start developing standards and partnerships to acquire new base map data.
  • Massachusetts has already developed a strategic plan. They will use their grant to develop a statewide base map, based on local tax maps and working closely with municipal governments.
    
    
  • In Mississippi the response to, and recovery from, Hurricane Katrina showed clearly the need to good statewide GIS data, and gaps in that data for the state. They will use their grant to start bridging those gaps.
  • Ohio will use their grant to develop standards and ways to work together among state and local government agencies.

  Category 4 Recipients
  
  

  • Washington DC has completed a strategic plan and will use their grant to develop a business plan to take the next steps and adapt to a changing geospatial industry.
  • In Hawaii, the state GIS council is voluntary and used their strategic plan to start to formalize its role. Development of a business plan will help them bring a large user-group/stakeholder community into the process and to focus on statewide base map data.
  • In Idaho, the strategic plan calls for regional user-groups to organize statewide data in regional segments, The southeast GIS user group will use their grant to develop that new idea and blaze the way for the other regions.
  • The strategic plan developed in Maine suggested a project to develop a statewide cadastral data set based on local government efforts supported by the statewide GIS community. They will use their grant for a pilot project in a representative county.
  • The state of New York will also use their grant to build on a cadastral data concept developed as part of their strategic plan. The will explore ways to integrate data from many local governments and share that data at a state level.
    
    

  Representatives from all of these states, DC, and from states that have been funded for strategic planning in the past, have gathered for a pre-conference workshop as part of the NSGIC Mid-Year meeting in Annapolis. Starting at 8:30 a.m. on Sunday, March 7, the workshop will review strategic and business planning processes and the states will share lessons-learned, ideas, and goals.
• 14:39

  CDC Unveils Fatal Injury Mapping ModelSpatial Sustain

  sur Planet Geospatial - http://planetgs.com
  The Center for Disease Control’s National Center for Injury Prevention and Control has just released an online fatal injury mapping model that allows you to query injury statistics to create custom maps of death rates throughout the United States. There’s a fascinating level of detail to this resource, including the intent of injury, ethnicity, age, [...]

• 13:47

  Where's My Bike with Google Maps

  sur Google Maps Mania
  GPS Bike Live TrackerWilfred Ketelaar of XL-Network has created a Google Maps mashup to show the current position of his bike. Wilfred has placed a GPS unit in his bike so that he can track the bike's movements and find it if it is stolen.The tracker automatically updates a Google Map every minute to show the current location of the bike. The red line on the map shows the last journey made. The

• 12:03

  OpenStreetMap 3DVector One

  sur Planet Geospatial - http://planetgs.com
  OpenStreetMap 3D is a project from the University of Heidelberg.  It is based upon open geodata and incorporates Shuttle Radar Topographic Mission (SRTM) digital elevation data. For the representation of information the 3D View ‘XNavigator’ is developed and used. The OpenStreetMap WebMapService of Europe is also incorporated and available for viewing here. The Cartographic Research Group [...]

• 2:07

  Un réchauffement climatique foudroyant : gare aux maisons les pieds dans l'eau

  sur Les Cafés géographiques
  Le climat de l'Atlantique Nord a connu un changement radical en très peu de temps à la fin de la dernière période glaciaire. Ce sont des carottes extraites des glaces du Groenland par des chercheurs de l'Institut Niels Bohr de l'Université de Copenhague qui le disent.
Année après année, la neige qui recouvre le Groenland se compacte en glace qui emprisonne des éléments du climat de l'année en cours. Les 3 km d'épaisseur de la calotte glaciaire sont ainsi une bibliothèque pour climatologues, renfermant plus (...)
• 2:07

  112 : Un réchauffement climatique foudroyant : gare aux maisons les pieds dans l'eau

  sur Les Cafés géographiques
  Le climat de l'Atlantique Nord a connu un changement radical en très peu de temps à la fin de la dernière période glaciaire. Ce sont des carottes extraites des glaces du Groenland par des chercheurs de l'Institut Niels Bohr de l'Université de Copenhague qui le disent.
Année après année, la neige qui recouvre le Groenland se compacte en glace qui emprisonne des éléments du climat de l'année en cours. Les 3 km d'épaisseur de la calotte glaciaire sont ainsi une bibliothèque pour climatologues, renfermant plus (...)

• 0:49

  Live in a Movie SetVerySpatial

  sur Planet Geospatial - http://planetgs.com

  Oscar time is here and several news sources have stories about vacationing in your favorite movie setting. The Telegraph UK article “Oscars 2010: film location holidays” explores locations of this year’s Oscar-nominated films such as Avatar,District 9, Precious, and Crazy Heart. Film induced tourism is a growing tourism draw according to books such as “Film-induced Tourism (Aspects of Tourism)”. Many tourism bureaus now have film tourism locations on their websites such as Scotland (Harry Potter, Chariots of Fire), Vancouver Island’s flash map of locations, and New York City’s wonderful “Scenes from the City“.