[Geoserver-users] Rasters, Tiles, and FME

Jonathan_Moules2 · December 14, 2012, 5:21pm

Hi List,

A few generic questions.

First: What are gridsets actually for? I know how to create them (the documentation is very good for that), but I can’t figure out what they’re for.

Second: I have a number of large rasters in JPEG2000 format (up to several GB in size). GeoServer can’t access these (we’re not going to use the extension). I have FME so can do lots of processing on them if needed: What’s the best way to serve these up? I was thinking of tiling them (WMS can serve tiled data right?). But then the question becomes, which tiling system do I use? There seem to be several:

imagePyramid - http://docs.geoserver.org/stable/en/user/tutorials/imagepyramid/imagepyramid.html?highlight=tiling
JDBC - http://docs.geoserver.org/stable/en/user/tutorials/imagemosaic-jdbc/imagemosaic-jdbc_tutorial.html?highlight=tiling
imageMosaic - http://docs.geoserver.org/stable/en/user/tutorials/image_mosaic_plugin/imagemosaic.html

What are the advantages/disadvantages of each? I’m guessing some are easier to create/use and possibly faster.

Thanks,
Jonathan

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Arne_Kepp1 · December 16, 2012, 11:23pm

If you want to have efficient caching it is crucial that clients ask for the tiles that you have already generated. Basically they need to know the grid that you are basing your tiles on (origin of the grid, size of each tile in terms geographical extent and in terms of pixel size). And you need to define this for every zoom level (because for a given resolution the tiles may not cover the full extent exactly).

The result is a set of grids, aka gridset, which all your clients need to know about and use. The most commonly used, but rarely the best, is the one Google- and Bing Maps use for Spherical Mercator.

Not the right person to ask what raster approach is the most efficient, but converting the JPEGs to GeoTIFFs with overviews and inner tiling will probably be quiet fast, even though they take up more space. Performance on that end is less important if you can use tile caching. You can have them act as one layer using imagemosaic.

-Arne

On 12/14/12 14:21 , Jonathan Moules wrote:

Hi List,
A few generic questions.

First: What are gridsets actually for? I know how to create them (the documentation is very good for that), but I can't figure out what they're for.

Second: I have a number of large rasters in JPEG2000 format (up to several GB in size). GeoServer can't access these (we're not going to use the extension). I have FME so can do lots of processing on them if needed: What's the best way to serve these up? I was thinking of tiling them (WMS can serve tiled data right?). But then the question becomes, which tiling system do I use? There seem to be several:

imagePyramid - http://docs.geoserver.org/stable/en/user/tutorials/imagepyramid/imagepyramid.html?highlight=tiling
JDBC - http://docs.geoserver.org/stable/en/user/tutorials/imagemosaic-jdbc/imagemosaic-jdbc_tutorial.html?highlight=tiling
imageMosaic - http://docs.geoserver.org/stable/en/user/tutorials/image_mosaic_plugin/imagemosaic.html

What are the advantages/disadvantages of each? I'm guessing some are easier to create/use and possibly faster.

Thanks,
Jonathan

This transmission is intended for the named addressee(s) only and may contain sensitive or protectively marked material up to RESTRICTED and should be handled accordingly. Unless you are the named addressee (or authorised to receive it for the addressee) you may not copy or use it, or disclose it to anyone else. If you have received this transmission in error please notify the sender immediately. All email traffic sent to or from us, including without limitation all GCSX traffic, may be subject to recording and/or monitoring in accordance with relevant legislation.

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Jonathan_Moules2 · December 19, 2012, 10:10am

Hi Arne,
Thanks for the reply. I get what gridsets do (further clarified by your reply), I don’t understand how to use them. What other parts of GeoServer do they interact with? Or what parts of the client software? And how do you get the client software to use the same gridsets? The documentation only tells me how to create them, it doesn’t say what I should do after that.

Unfortunately FME can’t create GeoTIFFs with overviews and possibly not inner tiling too. I’m aware GDAL does but we’d prefer to use FME.

Does anyone else have any suggestions how to process the rasters?
Cheers,
Jonathan

On 16 December 2012 23:23, Arne Kepp <arne@anonymised.com> wrote:

If you want to have efficient caching it is crucial that clients ask for the tiles that you have already generated. Basically they need to know the grid that you are basing your tiles on (origin of the grid, size of each tile in terms geographical extent and in terms of pixel size). And you need to define this for every zoom level (because for a given resolution the tiles may not cover the full extent exactly).

The result is a set of grids, aka gridset, which all your clients need to know about and use. The most commonly used, but rarely the best, is the one Google- and Bing Maps use for Spherical Mercator.

Not the right person to ask what raster approach is the most efficient, but converting the JPEGs to GeoTIFFs with overviews and inner tiling will probably be quiet fast, even though they take up more space. Performance on that end is less important if you can use tile caching. You can have them act as one layer using imagemosaic.

-Arne

On 12/14/12 14:21 , Jonathan Moules wrote:
Hi List,

A few generic questions.

First: What are gridsets actually for? I know how to create them (the documentation is very good for that), but I can’t figure out what they’re for.

Second: I have a number of large rasters in JPEG2000 format (up to several GB in size). GeoServer can’t access these (we’re not going to use the extension). I have FME so can do lots of processing on them if needed: What’s the best way to serve these up? I was thinking of tiling them (WMS can serve tiled data right?). But then the question becomes, which tiling system do I use? There seem to be several:

imagePyramid - http://docs.geoserver.org/stable/en/user/tutorials/imagepyramid/imagepyramid.html?highlight=tiling
JDBC - http://docs.geoserver.org/stable/en/user/tutorials/imagemosaic-jdbc/imagemosaic-jdbc_tutorial.html?highlight=tiling
imageMosaic - http://docs.geoserver.org/stable/en/user/tutorials/image_mosaic_plugin/imagemosaic.html

What are the advantages/disadvantages of each? I’m guessing some are easier to create/use and possibly faster.

Thanks,
Jonathan

This transmission is intended for the named addressee(s) only and may contain sensitive or protectively marked material up to RESTRICTED and should be handled accordingly. Unless you are the named addressee (or authorised to receive it for the addressee) you may not copy or use it, or disclose it to anyone else. If you have received this transmission in error please notify the sender immediately. All email traffic sent to or from us, including without limitation all GCSX traffic, may be subject to recording and/or monitoring in accordance with relevant legislation.
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