Coast gis talk
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This document provides tools and best practices for creating coastal web maps. It discusses options for data storage, including hosting locally or in the cloud. Common data formats like Shapefiles, GeoJSON and GeoTIFF are recommended. It also covers web mapping services like WMS, WFS and WMTS based on OGC standards. Popular client-side development options are presented, such as APIs from Google Maps and ArcGIS, and open-source libraries like OpenLayers and Leaflet. Resources for further information are provided.
Coast gis talk
- 1. Tools and Best Practices for Coastal Web Maps Carl Sack University of Wisconsin Sea Grant
- 2. (Some) Options for Making Web Maps
- 4. Web Mapping: A Basic Framework 1. Data Storage 1. Location 2. Types 3. Projection & CRS 2. Web Mapping Services 1. OGC Standards 3. Client Libraries and APIs 1. API 2. Code library 3. Framework 4. Plug-in Disclaimer: suggestions are based on broad survey knowledge and should not be considered definitive!
- 5. Data Storage Where 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
- 6. Data Storage • Vector data: – Best stored in SQL database – PostGIS, MySQL, SQLite, Oracle, Microsoft – KML, GML, Shapefile, GeoJSON most popular transfer formats – OGR2OGR to change formats easily (GDAL/OGR Library) • Raster data: – No advantage to database vs. file structure – GeoTIFF most popular for georeferenced images – Web services (WMS, Tiles) in JPEG and/or PNG
- 7. 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 continuously and without wild distortion – Equal-area projections more appropriate for choropleth maps, but rare. Supported by OpenLayers and Google Maps API. – Unlikely to need equal-area for coastal features
- 8. Web Services OGC Standards: • WMS: Most well-used; map images • WFS: Vector data • WPS: Server-side data processing • CSW: Catalog Services • WMTS: Tiles All standards on http://www.opengeospatial.org • Vital for interoperability!
- 9. Web Services REST Interface Client: http://neowms.sci.gsfc.nasa.gov/wms/wms? VERSION=1.3.0&REQUEST=GetMap&LAYERS=MOD_LSTD_CLIM_M&WIDTH=960&HEIG HT=600&FORMAT=image/jpeg&CRS=CRS:84&BBOX=-180,-90,180,90 Server: Most Common: •Map Server •GeoServer •ArcGIS For Server
- 10. Web Services WMS process: • Style the data • Render the image • Send the image to client WFS process: • Reformat the data • Send GML to client • Data styled and rendered by client
- 11. Web Services Tiles (WMTS): • Server generates tiles on the fly or serves pre-rendered images • Caching increases speed of delivery • Stored in specialized directory structure: http://www.server.com/tiles/{z}/{x}/{y}.png
- 12. Client-Side Development Some vocabulary: • Code Library: script that simplifies map display and interaction in a client browser • API: a partly-hidden code library controlled by a proprietary service • Framework: an all-in-one solution • Plug-in: a program that runs compiled code inside of a browser (Flash, Flex, Java, Silverlight)
- 13. Client-Side Development Popular APIs: • Google Maps API v3 – Popular for public mash-ups, but size- limited, costs • ArcGIS Online API – JavaScript, iOS, Android flavors, but large, license costs
- 14. Client-Side Development Popular open-source libraries: • OpenLayers – Oldest, most robust open- source library, but huge and hard to figure out • Leaflet – Lightweight, good documentation, easy to extend, lots of plugins • D3 – Vector data loading and mapping with many projection, styling, and interaction possibilities
- 15. Client-Side Development Other 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 making simple web maps • Ushahidi Crowdmap – Crowdsourced geographic information
- 16. Some Resources Wright, D., N. Dwyer, and V. Cummins (eds.). 2011. Coastal Informatics: Web Atlas Design and Implementation (Information Science Reference), New York, NY, USA: 33-52. Wolfgang, K. and D.M. Danko (eds.). 2012. Springer Handbook of Geographic Information (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.pdf OGC Standards: http://www.opengeospatial.org
- 17. Thank you! Questions? Contact Carl Sack [email protected] @northlandiguana Resources http://giscollective.org/tutorials/web-mapping www.northlandia.com/pdf/coastalwebmaps.pdf