How can I confirm the existence of pyramids in QGis?
I have created pyramid layers for my ASTER satellite images (.img) using Gdal Tools “Build Overviews” (Pyramids). The dialog said “Processing completed”. I don’t have the impression that zooming in or...
View ArticleLack of Options in Gdal Tool “Build Overviews” QGis
I am using QGis 1.8 and I want to build overviews (pyramids) for satellite imagery using the Gdal Tool. I would like to use the resampling method “cubic convolution”, but the option doesn’t exist...
View ArticleUSGS FLT Hdr file interpretation
I have a legacy program that attempts to read USGS 1/3 arcsec data. When I compare results to GDAL, I find that the lat/lon to pixel conversion is off by 1 line. The reason (I think) is because the...
View ArticleOSM linestring shown as point
I have loaded the following file http://openstreetmapdata.com/data/coastlines to postgreSQL. In visual studio with gdal/ogr and geos enabled: SELECT geom FROM waterpoly WHERE geom IS NOT NULL LIMIT 10;...
View ArticleLSA-SAF data reprojection with GDAL and R
The Land Surface Analysis Satellite Applications Facility (LSA SAF) distributes several products derived from the EUMETSAT satellites data. I am working with R to read and process the data (the file of...
View ArticleWhat are the differences between the photometric options for GDAL_merge?
I am using GDAL_merge to merge several geotiff tiles into one large tile. One of the creation options I can add is photometric. There are several options for this. MINISBLACK MINISWHITE RGB CMYK YCBCR...
View ArticleClik here to view.
How to properly convert EPSG:3857 to EPSG:4326 tif?
I tried using the answer from “Transforming EPSG:3857 to EPSG:4326” to do this but gdalinfo tells me that this didn’t really work properly. Driver: GTiff/GeoTIFF Files: geo-map.tif Size is 1024, 512...
View ArticleHow to use gdal module in python
i am trying to import gdal modules from osgeo installed in my win64x machine but i get the following error. i am using the python shell from arcgis 10.1 that comes with python 2.7.2 Traceback (most...
View ArticleOptimising Min/Max temporal raster search in python/gdal
I need to search across ~100 1200×1200 raster tiles and produce a min and a max raster. Along the way i also want to exclude values that are over 1 or less than 0. What would be the quickest method to...
View ArticleClik here to view.
Invert gdaldem aspect
I am trying to identify lakes and other water bodies in a DEM file. The source file is located here. I am using gdaldem aspect to identify contiguous pixels with zero slope change. gdaldem aspect -co...
View Articleimporting osgeo module in ubuntu 10.04
I have problem with importing “osgeo” module in ubuntu 10.04; I have installed GDAL 1.7 from source ( 1)./configure 2)make) however, still in python I cant import osgeo module. I appreciate any hints....
View ArticleMaking development patterns more efficient with ZSH
A common pattern I find myself encountering is converting a CSV to a projected GeoJSON as described here. That entails 3 steps, and I’d like to get it down to the following: GEOIFY {file}...
View ArticleWhat does the predictor switch do while compressing geoTIFFs in GDAL
I am merging several geoTIFF into one and am using the -co COMPRESS=DEFLATE create option for geoTIFFs. An additional switch is the predictor switch. What does it do? The GDAL website is not clear on...
View ArticleWhat are the datasource formats in OGR [on hold]
here in this tutorial you see that the format of the datasource is .shp meaning that it can just have one layer. I want to know what are the datasources that gdal suppots? and can have more than 1...
View ArticleDriver error when converting MapInfo file to Shapefile with ogr2ogr
I am trying to convert a MapInfo file to an ESRI shapefile using GDAL‘s ogr2ogr command as described here, but I am getting the following error: FAILURE: Unable to open datasource `Iceland2pts.mif'...
View ArticleIs georeference the same as geotransform?
Does georeference mean the same as geotransform? If not then what is the difference?
View ArticleGeoPDF Support in GDAL
I installed OSGeo4W using a Windows installer… it contains GDAL 1.7.3. I can’t get GDAL to recognize PDF as a file type using commands in MSYS shell. Does this version of GDAL not support PDFs? If not,...
View ArticleHow do I know the vertical/horizontal units of my DEM? I'm creating a slope...
I’m using gdaldem to create a slope map. I can apply a scale. The default is 1. The notes say: Ratio of vertical units to horizontal. If horizontal unit of source DEM is degrees (e.g WGS84 projection),...
View ArticleDisplaying DEM raster in QGIS
Using Raster>Analysis>DEM to display hillshade produces the message “gdaldem.exe had stopped working” so I asked the community. I’m new to QGIS, and I now realise after a little experimentation...
View ArticleHow to convert 4-channel PNG files to grayscale geoTIFFs?
I suspect that there exists a gdal tool (gdal_translate?) that will convert a 4-channel PNG (+ world file) to a 1-channel (gray-scale) geoTIFF. From the gdal_translate man page, it appears simple to go...
View Article