[gdal-dev] gdal2tiles with GeoTIFF which crosses antimeridian?

Sat Nov 28 07:44:14 PST 2020

Good Morning,

I have a stackoverflow on this issue if anyone can give some info. It turns
out that if you force the resolution in the warp, the resulting file does
look good.

https://gis.stackexchange.com/questions/380002/issue-creating-tiles-from-geotiff-which-crosses-the-180th-meridian/

On Thu, Nov 26, 2020 at 10:01 AM James Russo <jr at halo3.net> wrote:

> Lars,
>
> Sorry! My apologies. Despite double checking, there was a copy and paste
> error in the script. The second gdalwarp with the -te was outputting to the
> same path as the no sliced version. Corrected script below. I appreciate
> you looking into this with me!
>
> *additionally, My original reply directly to you also included a typo.
> This script should be good!
>
> -jr
>
> ---snip---
> #!/bin/bash
>
> wget -SN
> https://aeronav.faa.gov/content/aeronav/Planning/AK_WallPlan_2.zip &&
> unzip -xo AK_WallPlan_2.zip
> mv "Alaska Wall Planning Chart 2.tif" Alaska_Wall_Planning_Chart_2.tif
> gdal_translate  -expand rgb  -strict  -co TILED=YES -co COMPRESS=LZW  -co
> BIGTIFF=YES Alaska_Wall_Planning_Chart_2.tif alaska_expanded_rgb.vrt
> gdalwarp -t_srs EPSG:3857 -r lanczos -overwrite -multi -wo
> NUM_THREADS=ALL_CPUS -wm 1024 --config GDAL_CACHEMAX 1024 -co TILED=YES
> alaska_expanded_rgb.vrt alaska_warped.vrt
> gdalwarp -t_srs EPSG:3857 -te -19979999 6016546 -13438444 11497579 -r
> lanczos -overwrite -multi -wo NUM_THREADS=ALL_CPUS -wm 1024 --config
> GDAL_CACHEMAX 1024 -co TILED=YES alaska_expanded_rgb.vrt
> alaska_warped_sliced_at_180.vrt
> rm -rf alaska_tiles_no_slice
> rm -rf alaska_tiles_sliced_at_180
> gdalinfo alaska_warped.vrt
> time gdal2tiles.py -vvv -z 0-9 --processes=16 -r lanczos -w leaflet
> alaska_warped.vrt alaska_tiles_no_slice
> gdalinfo alaska_warped_sliced_at_180.vrt
> time gdal2tiles.py -vvv -z 0-9 --processes=16 -r lanczos -w leaflet
> alaska_warped_sliced_at_180.vrt alaska_tiles_sliced_at_180
>
> ---snip---
>
> On Thu, Nov 26, 2020 at 9:55 AM <lars.schylberg at blixtmail.se> wrote:
>
>> Hi,
>>
>> I tried to reproduce your experiment. It seems like the command that
>> produces "alaska_warped_sliced_at_180.vrt" is missing in your script.
>> I guess that step could be vital to understand what is going on.
>>
>> Best regards
>>
>> /Lars Schylberg
>>
>> 26 november 2020 kl. 03:42, "James Russo" <jr at halo3.net
>> <jr at halo3.net?to=%22James%20Russo%22%20%3Cjr at halo3.net%3E>> skrev:
>>
>> Good Evening,
>> I'm just following up on this question from a few days ago with some more
>> information and the script I am using which reproduces this issue.
>> The example results can be found here at the s3 links below and are all
>> generated from the same original GeoTIFF. The only difference is that on
>> one of them I slice off all data left of the 180, the other one the map is
>> left complete. The html files are set to the same example point and zoom
>> level to show how that without slicing the file, the image quality is very
>> poor. The one thing I notice is that if I include the 180 meridian, the
>> number of tiles generated is far larger (46k vs 8k).
>> Bad Results:
>>
>> http://halo3.net/alaska_tiles_no_slice/leaflet.html
>>
>> Good Results:
>>
>> http://halo3.net/alaska_tiles_sliced_at_180/leaflet.html
>>
>> Below is the script I use to generate both tile sets. It will
>> automatically download, unzip and process the input file I am using
>> producing the same results shown at the links above.
>> I'd appreciate any insight into the issue and how I might be able to get
>> it resolved? I'm still quite a novice at all this GIS stuff, but it has
>> been a fun experience so far.
>> Thanks,
>> -jr
>> ---snip---
>> #!/bin/bash
>> wget -SN
>> https://aeronav.faa.gov/content/aeronav/Planning/AK_WallPlan_2.zip &&
>> unzip -xo AK_WallPlan_2.zip
>> mv "Alaska Wall Planning Chart 2.tif" Alaska_Wall_Planning_Chart_2.tif
>> gdal_translate -expand rgb -strict -co TILED=YES -co COMPRESS=LZW -co
>> BIGTIFF=YES Alaska_Wall_Planning_Chart_2.tif alaska_expanded_rgb.vrt
>> gdalwarp -t_srs EPSG:3857 -r lanczos -overwrite -multi -wo
>> NUM_THREADS=ALL_CPUS -wm 1024 --config GDAL_CACHEMAX 1024 -co TILED=YES
>> alaska_expanded_rgb.vrt alaska_warped.vrt
>> gdalwarp -t_srs EPSG:3857 -te -19979999 6016546 -13438444 11497579 -r
>> lanczos -overwrite -multi -wo NUM_THREADS=ALL_CPUS -wm 1024 --config
>> GDAL_CACHEMAX 1024 -co TILED=YES alaska_expanded_rgb.vrt alaska_warped.vrt
>> rm -rf alaska_tiles_no_slice
>> rm -rf alaska_tiles_sliced_at_180
>> gdalinfo alaska_warped.vrt
>> time gdal2tiles.py -vvv -z 0-9 --processes=16 -r lanczos -w leaflet
>> alaska_warped.vrt alaska_tiles_no_slice
>> gdalinfo alaska_warped_sliced_at_180.vrt
>> time gdal2tiles.py -vvv -z 0-9 --processes=16 -r lanczos -w leaflet
>> alaska_warped_sliced_at_180.vrt alaska_tiles_sliced_at_180
>> ---snip---
>> On Tue, Nov 24, 2020 at 6:20 AM James Russo <jr at halo3.net> wrote:
>>
>> Good Evening,
>> GIS novice here. I have a GEOTiff that I'm trying to create tiles from
>> which crosses the 180. It's a FAA sectional chart from the US used for
>> aviation. If I slice off anything west of the 180, I can generate the tiles
>> and they look good. If I don't the area of the tiles is super large and the
>> resulting tile set is very pixelated.
>> The source file is located here in zip form (
>> https://aeronav.faa.gov/content/aeronav/Planning/AK_WallPlan_2.zip)
>> I've tried some of the solutions that specify to use the CONFIG_LONG
>> option, but that doesn't seem to be impacting anything. The only solution I
>> have come up with is to cut off the area which crosses the 180 which yields
>> good results.
>> I've included below the commands I've been using. I'm looking for any
>> suggestions/guidance. I realize this is somewhat of a common problem. Even
>> MapTiler had the problem, but they have sent an updated version which
>> supposedly fixes it, but I can't afford that solution at this point so I'd
>> like to stick to GDAL if possible.
>> Thanks,
>> -jr
>> --- snip --
>> gdal_translate \
>> -expand rgb \
>> -strict \
>> -co TILED=YES \
>> -co COMPRESS=LZW \
>> -co BIGTIFF=YES \
>> alaska.tif alaska_expanded_rgb.vrt
>>
>> gdalwarp \
>> -overwrite \
>> -cutline "Alaska_Wall_Planning_Chart.shp" \
>> -crop_to_cutline \
>> -cblend 10 \
>> -r lanczos \
>> -dstalpha \
>> -co ALPHA=YES \
>> -co TILED=YES \
>> -multi \
>> -wo NUM_THREADS=ALL_CPUS \
>> -wm 1024 \
>> --config GDAL_CACHEMAX 1024 \
>> "alaska_expanded_rgb.vrt" \
>> "alaska_clipped.vrt"
>>
>> gdalwarp \
>> -t_srs EPSG:3857 \
>> -te -19497422 6016546 -13438444 11497579 \
>> -r lanczos \
>> -overwrite \
>> -multi \
>> -wo NUM_THREADS=ALL_CPUS \
>> -wm 1024 \
>> --config GDAL_CACHEMAX 1024 \
>> -co TILED=YES \
>> "alaska_clipped.vrt" \
>> "alaska_warped.vrt"
>> gdal2tiles.py -z 0-8 --processes=16 -r lanczos -w leaflet
>> alaska_warped.vrt
>>
>>
>>
>>
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