Viewing posts for the category gdal

More to maps than markers

Posted by: Will Cadell in esri user experience mapping web development code gdal postgis GIS open source tools google maps consulting leaflet 2 years, 7 months ago

Google Maps have been with us since February 2005, virtually a decade ago as I write this (expect a party on Feb 8th 2015). From their acquisitions of Where 2 Technologies and Keyhole, Google ignited a cartographic web revolution. Yes, of course there were maps on the internet pre-Google Maps, but Google brought the web map to the consumer, and has driven the expectation of location intelligence in web and mobile apps ever since.

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Step Up Your Raster Handling Skills

Posted by: Kaela Perry in mapping code gdal GIS Open Source Tools google maps 3 years, 7 months ago

It is not uncommon for raster data to be large and unruly. Creating tiles is one way to deal with these large datasets and speed up rendering. This post introduces a few handy tools for dealing with raster data while walking through the process of combining multiple raster files to create tiles for a super-overlay for a nice clean visual output that renders more efficiently (particularly in Google Earth). All from the command line.

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GDAL & OGR clipping (hack)

Posted by: Will Cadell in gdal mapping technology open source tools GIS 4 years, 6 months ago

Today I had to clip a raster image by 102,000 polygon features. With out doubt this task demanded automation. I decided to try my hand at python coding using the excellent GDAL library. I had this great idea that i could do the whole thing nicely in GDAL, but i was foiled by time (or not enough of it) and I did half of the process in a pure GDAL script then I dropped to the cmd line to execute gdal_translate with a changing projwin per iteration. In case you are unaware with the gdal library comes a series of astonishingly useful utilities. I used to use the FWTools port but now I use the OSGeo4w one instead. There are a number of raster processing wonder-tools in here, and gdal_translate is one of them! Back to my script, I realize now that in actual fact i am using almost exclusively OGR pieces of GDAL, confused yet?. Its simple: GDAL = rasters OGR = Vectors I start by importing:

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PostGIS to PostGIS via ogr2ogr

Posted by: Will Cadell in technology code ogr2ogr gdal postgis GIS open source tools 4 years, 6 months ago

OGR2OGR is a hugely useful GIS utility. Today I was using it to copy data between an Amazon Web Services (AWS) based PostGIS database and a local PostGIS database. This is a slightly weird use case, but I wanted to pull down some data locally for editing via Quantum GIS (QGIS).

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