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Coast gis talk
Coast gis talk
Coast gis talk
Coast gis talk
Coast gis talk
Coast gis talk
Coast gis talk
Coast gis talk
Coast gis talk
Coast gis talk
Coast gis talk
Coast gis talk
Coast gis talk
Coast gis talk
Coast gis talk
Coast gis talk
Coast gis talk
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Coast gis talk

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  • 1. Tools and Best Practicesfor Coastal Web MapsCarl SackUniversity of Wisconsin Sea Grant
  • 2. (Some) Options for Making Web Maps
  • 3. Web Mapping: A Basic Framework1. Data Storage1. Location2. Types3. Projection & CRS2. Web Mapping Services1. OGC Standards3. Client Libraries and APIs1. API2. Code library3. Framework4. Plug-inDisclaimer: suggestions are based on broad survey knowledgeand should not be considered definitive!
  • 4. Data StorageWhere to put it?• Local host machine:– Easy access to hardware– Maintenance and limited speed• Cloud host (Amazon, Esri, CartoDB)– High bandwidth, no hardware maintenance– Distributed back-ups– Ongoing cost
  • 5. Data Storage• Vector data:– Best stored in SQL database– PostGIS, MySQL, SQLite, Oracle, Microsoft– KML, GML, Shapefile, GeoJSON most popular transferformats– OGR2OGR to change formats easily (GDAL/OGRLibrary)• Raster data:– No advantage to database vs. file structure– GeoTIFF most popular for georeferenced images– Web services (WMS, Tiles) in JPEG and/or PNG
  • 6. Data Storage• Projection and CRS– Store in same SRS as it will be used– Projections required for slippy map:• EPSG:3857 (EPSG:900913) – Spherical Mercator– Advantageous for complex shapes (coastlines, e.g.)• EPSG:4326 – Plate Carrée (less common)– Less distortion poleward• Other projections– Must be rectangular to cover the whole globe continuouslyand without wild distortion– Equal-area projections more appropriate for choroplethmaps, but rare. Supported by OpenLayers and Google MapsAPI.– Unlikely to need equal-area for coastal features
  • 7. Web ServicesOGC Standards:• WMS: Most well-used; map images• WFS: Vector data• WPS: Server-side data processing• CSW: Catalog Services• WMTS: TilesAll standards on http://www.opengeospatial.org• Vital for interoperability!
  • 8. Web ServicesREST InterfaceClient:http://neowms.sci.gsfc.nasa.gov/wms/wms?VERSION=1.3.0&REQUEST=GetMap&LAYERS=MOD_LSTD_CLIM_M&WIDTH=960&HEIGHT=600&FORMAT=image/jpeg&CRS=CRS:84&BBOX=-180,-90,180,90Server:Most Common:•Map Server•GeoServer•ArcGIS For Server
  • 9. Web ServicesWMS process:• Style the data• Render the image• Send the image to clientWFS process:• Reformat the data• Send GML to client• Data styled and rendered by client
  • 10. Web ServicesTiles (WMTS):• Server generatestiles on the fly orserves pre-renderedimages• Caching increasesspeed of delivery• Stored in specializeddirectory structure:http://www.server.com/tiles/{z}/{x}/{y}.png
  • 11. Client-Side DevelopmentSome vocabulary:• Code Library: script that simplifies mapdisplay and interaction in a client browser• API: a partly-hidden code library controlledby a proprietary service• Framework: an all-in-one solution• Plug-in: a program that runs compiled codeinside of a browser (Flash, Flex, Java,Silverlight)
  • 12. Client-Side DevelopmentPopular APIs:• Google Maps API v3– Popular for publicmash-ups, but size-limited, costs• ArcGIS Online API– JavaScript, iOS,Android flavors, butlarge, license costs
  • 13. Client-Side DevelopmentPopular open-source libraries:• OpenLayers– Oldest, most robust open-source library, but huge andhard to figure out• Leaflet– Lightweight, gooddocumentation, easy to extend,lots of plugins• D3– Vector data loading andmapping with many projection,styling, and interactionpossibilities
  • 14. Client-Side DevelopmentOther Cool Stuff:• GeoMoose, Geomajas, GeoExt– All-in-one frameworks• CartoDB– Entierly cloud-based toolchain• Geocommons, ArcGIS Online Viewer– Online sources of data and applications for makingsimple web maps• Ushahidi Crowdmap– Crowdsourced geographic information
  • 15. Some ResourcesWright, D., N. Dwyer, and V. Cummins (eds.). 2011. Coastal Informatics: WebAtlas Design and Implementation (Information Science Reference), New York,NY, USA: 33-52.Wolfgang, K. and D.M. Danko (eds.). 2012. Springer Handbook of GeographicInformation (Springer), New York, NY, USA: 61-122.Davis, S. 2007. GIS for Web Developers: Adding ‘Where’ to Your Web Applications,The Pragmatic Bookshelf, Raleigh, NC, USA, 176p.Roth R.E., R.G. Donohue, C.M. Sack, T.R. Wallace, and T.M.A. Buckingham.2013. “A Process for Assessing Emergent Web Mapping Technologies.” In:Proceedings of the 26th International Cartographic Conference. Dresden,Germany: August 25-30. www.northlandia.com/pdf/RothEtAl2013.pdfOGC Standards: http://www.opengeospatial.org
  • 16. Thank you! Questions?ContactCarl Sackcmsack@wisc.edu@northlandiguanaResourceshttp://giscollective.org/tutorials/web-mappingwww.northlandia.com/pdf/coastalwebmaps.pdf

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