[gdal-dev] Generating 200x200 tiles

[Alistair Young]

thanks for that. I downloaded the TFW and TAB files from the Ordnance Survey, put them in the same directory as the tif and did:

gdal_translate -of VRT -a_srs EPSG:27700 sx88.tif out.vrt

And ran ctb-tile on out.vrt. It tiled it but into what appear to be weird columns and rows. E.g. Col 14, row 16046 etc. The SDK fails to read this as I suspect it expects 20 cols and 20 rows (it’s 5 metres per pixel resolution)

I’m not sure what ullr is for. There’s no  information about the tif (it’s a British National Grid Square 20kmx20km) but I’ve no idea what lat/lon it covers.

Alistair


-----------------
mov eax,1
mov ebx,0
int 80

From: <gdal-dev-bounces at lists.osgeo.org<mailto:gdal-dev-bounces at lists.osgeo.org>> on behalf of Homme Zwaagstra <hrz at geodata.soton.ac.uk<mailto:hrz at geodata.soton.ac.uk>>
Date: Monday, 21 September 2015 08:29
To: "gdal-dev at lists.osgeo.org<mailto:gdal-dev at lists.osgeo.org>" <gdal-dev at lists.osgeo.org<mailto:gdal-dev at lists.osgeo.org>>
Subject: Re: [gdal-dev] Generating 200x200 tiles



On 19/09/15 08:14, Alistair Young wrote:
> Thanks for that. I tried ctb but just got "Could not get transformation > information from source dataset². Chaning gdal2tiles to output 200x200 > worked ok but the SDK failed to display the tiles. I just have a 4000x4000 > tif with no geo referencing information so I can only generate raster > profile tiles.

Alistair, you'll have trouble getting anything useful out of any geospatial
tools without inputting datasets that are correctly georeferenced with an
appropriate spatial reference system.  Assuming you know the extents of your
4000x4000 raster, you should be able to do this by creating a virtual raster
with gdal_translate using options along the following lines:

   gdal_translate -of VRT -a_srs srs_def -a_ullr ulx uly lrx lry in.tif out.vrt

Passing out.vrt to ctb should resolve the error, and you'll have more chance
with other tools too.

Best regards,

Homme

> > Alistair > > > ----------------- > mov eax,1 > mov ebx,0 > int 80 > > > > > On 18/09/2015 00:36, "gdal-dev-bounces at lists.osgeo.org<mailto:gdal-dev-bounces at lists.osgeo.org> on behalf of Brad > Hards" <gdal-dev-bounces at lists.osgeo.org on behalf of bradh at frogmouth.net><mailto:gdal-dev-bounces at lists.osgeo.orgonbehalfofbradh@frogmouth.net> > wrote: > >> On Thu, 17 Sep 2015 06:03:15 PM Alistair Young wrote: >>> I've been using gdal2tiles to generate zoom levels and tiles and it's >>> working fine but unfortunately the tiles are 256x256 and don't work with >>> the UK Ordnance Survey mapping SDK, which requires 200x200 tiles. Is >>> there >>> a way to generate these 200x200 tiles? I can generate them using >>> gdal_retile but it can't generate the zoom levels. >> I'd suggest just hacking the python script.  Make a copy, and edit the >> __init__() function to change the tileSize member init to be 200 vs 256. >> >> Worth a quick try at least. >> >> Brad >> >> >> _______________________________________________ >> gdal-dev mailing list >> gdal-dev at lists.osgeo.org<mailto:gdal-dev at lists.osgeo.org> >> http://lists.osgeo.org/mailman/listinfo/gdal-dev > > _______________________________________________ > gdal-dev mailing list > gdal-dev at lists.osgeo.org<mailto:gdal-dev at lists.osgeo.org> > http://lists.osgeo.org/mailman/listinfo/gdal-dev


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