Photogrammetric like ortho-photos rendered with GDAL/PostGIS from 3D point clouds created in Bundler and PMVS? Yes indeedeedoo: Point cloud in meshlab: And “orthophoto” derived from voronoi polygons in PostGIS, rendered to tif with gdal: Hat tip to my3dscanner for making it so easy to generate the point cloud. More on this later. Continue reading Photogrammetry using Bundler, PMVS, GDAL, and PostGIS.
I show a simple example today of using gdal tools to change from raster to polygons with Bash. That’s right. Still no pythonista here. I have poked ever so gently at the surface of ruby and rails recently, while watching another coder re-tune his brain to a new set of principles of least surprise. By the way, for my regular readers, please be patient with … Continue reading Reprocessing imagery with GDAL and BASH — and then cleaning up afterward
I just can’t seem to get away from Bash. One day I promise to do the same work with Python, but for now, the following will take your directory of 3-band imagery, extract the first band, and if it succeeds, delete your original file. Seeing as I had almost 300GB of imagery, and very little space left, this kind of housekeeping was necessary (my other … Continue reading Reprocessing imagery with GDAL and BASH — and then cleaning up afterward
A perennial favorite on this blog is “GeoServer and efficient delivery of raster data (image pyramid layer)“. I am neither the last nor the first authority on this topic (check the GeoSolutions blog for authoritative work on GeoServer and raster, also look to the GeoServer documentation), but I’ve had some good experiences with serving rasters in GeoServer, especially using image pyramid layers Read the original, … Continue reading GeoServer and efficient delivery of raster data (image pyramid layer) (update)
Mini GDAL tip of the day: gdalwarp, especially in combination with gdal_merge, is a powerful tool for doing all sorts on nice aggregation (read: mosaic’ing) of spatial raster data. Unfortunately, at least with a google search, there’s very little to be found on demonstrating the use of queries in conjunction with cutlines, probably because in general these queries are not difficult to figure out. In … Continue reading gdal_warp, cutlines, and cwhere– simple tip for use on Linux
Open Source software is not, of course just about warm and fuzzies, great support, rapid development cycles, shared costs, etc., it’s also about getting your hands dirty with someone else’s code and implementing stuff more quickly and more intelligently because of it, and hopefully learning something in the process. You don’t have to poke under the hood to drive the car, but sometimes it’s nice … Continue reading GDAL Slopes– Local Hydrologic Slope vs. the Standard Approach
gdal_calc is a python script that makes it easy to do band math and logical operations with gdal/numby. This ranges from basic arithemtic operations to logical functions. And while gdal_calc.py has been around since 2008, it is but is a recent and revelatory discovery for me. I had just today resigned myself to properly learning python so as to use the gdal bindings. But, my … Continue reading gdal_calc.py– Raster Calculator using Numby Functions
Translating MrSid lossy compressed files into uncompressed imagery has its drawbacks, including licensing and artifacts. Old versions of fwtools, which includes the GDAL utilities (and more), were compiled with a license that allowed for the translation of MrSid into e.g. Erdas Imagine images or GeoTiff. The licensing changed on that library, so FWTools and MS4W don’t do this anymore. If you have a compiled version … Continue reading GDAL, MrSid, and nearblack
One thing I’ve learned in the last few years is that there is no theoretical reason why (properly indexed and summarized) data cannot be displayed at all scales as quickly as at any scale. This is the principle at work behind the extraordinary efficiencies of delivering data and imagery through a slippy map interface like Google, Bing, and OpenLayers as well as efficient thick client … Continue reading GeoServer and efficient delivery of raster data (image pyramid layer)
This will be a very quick post today. We wanted to use some historical USGS quads for analysis. We had a ready source, used ArcGIS to georeference them to a grid, but then wanted something approaching a seamless product. Enter gdal. First step, create an image to put the mosaic into: gdal_merge -o usgs_merge.tif -createonly input1.tif input2.tif … Then mosaic into that. Since we have … Continue reading Historical USGS Quads
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