robintw
  • Member for 11 years, 6 months
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When did the word "geospatial" first come into usage?
15 votes

The Google Books NGram dataset is a perfect way to answer this - it shows the frequency of words or phrases in the Google Books corpus (basically all text in all books, journals, magazines etc that ...

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Which Tools do you use for Classification of Remote Sensing Data?
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13 votes

I use a number of tools depending on the type of classification I am trying to perform. For general unsupervised/supervised classification I use ENVI, which has many options for classification ...

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How sensitive is Landsat to atmospheric correction?
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11 votes

Generally the answer is "Quite a large effect", but it can vary significantly. In general - do atmospheric correction if possible, and the best atmospheric correction you can - although I ...

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6S atmospheric correction results wrong
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10 votes

Short answer: It's a numerical precision issue: the xa, xb and xc coefficients are not displayed in the 6S output file with enough precision to produce the correct answer when using the formula. It is ...

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Seeking Australian Spatial Data?
8 votes

My list of Free GIS Data lists freely available GIS data for various countries including Australia. Unfortunately there is only one link for Australia, but that is to a government site which seems to ...

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Using R with ArcGIS Desktop?
7 votes

The Geospatial Modelling Environment (the successor of Hawth's Tools for ArcGIS) links python scripting, R and ArcGIS in a useful way. I haven't investigated the links with R in detail, but it looks ...

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How to use the same ROI for multiple LANDSAT images in ENVI?
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6 votes

ROIs in ENVI are stored in pixel-based co-ordinates, with no geographic information at all. The size of the image used to create the ROI is stored in the ROI file, and when you open the ROI list for ...

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Comprehensive database of all cities/towns in South Africa?
5 votes

I put a list online a while back of a number of free GIS datasets (see http://freegisdata.rtwilson.com/). Two that may be relevant to you are: Natural Earth populated places - although this is likely ...

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Open access repository of general GIS spatial data?
4 votes

I've tried to create a site a bit like the online repository that you want. My Free GIS data list provides links to a huge amount of data, sorted by category. The sort of data that is available ...

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What are the licence limitations on the free Ordnance Survey (OS) data sets?
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4 votes

The full license text is available at the OS website. Looks relatively simple - you can use it commercially if you want, but you must attribute them.

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Writing shapefile with projection defined crashes fiona
3 votes

This turned out to be an issue with the GDAL installation on my computer, and an incompatability between the various versions of GDAL, its supporting libraries (such as PROJ and GEOS) and Python. ...

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What is the best/easiest way to obtain temporal Landsat imagery?
3 votes

I find the USGS NewEarthExplorer to be the easiest way to download Landsat scenes. As I discuss in a blog post, it has a far more 'modern' interface which makes it easier to select appropriate images ...

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Reading BSQ file format in IDL?
3 votes

Are you using IDL with ENVI, or by itself? If you're using IDL with ENVI (by far the easiest if you have ENVI) then the standard ENVI file reading commands will work. For example: ENVI_SELECT, fid=...

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gdalinfo gives no georeferencing information for a PostGIS raster
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2 votes

I have now found the answer to this question, thanks to Bborie Park on the PostGIS-Users mailing list. Basically, by default when communicating with PostGIS, GDAL uses a setting called mode with a ...

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ENVI EX reviews?
2 votes

In my experience, ENVI EX provides a rather simplistic method for performing feature extraction using object-based image analysis. I investigated using ENVI EX for a project involving image ...

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In the UK, how do I convert from an address to a lat/long?
2 votes

The most accurate way to do this is to use the Ordnance Survey AddressPoint dataset. Their price list seems to suggest that for use on just one terminal costs around £16,000. However, if you are ...

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