[mapserver-users] MapServer returns a blank image when requesting a square image

[Pablo Sanfilippo]

I'm actually using MapServer 7.1 and it works fine as long as I'm using
4326 to request the tiles (whatever projection the sources of tileindex are
in). The problem is when I make the request using 3857 and the height of
the image is greater or equal to the width.

On Thu, Jan 11, 2018 at 1:02 PM, Rahkonen Jukka (MML) <
jukka.rahkonen at maanmittauslaitos.fi> wrote:

> Hi,
>
>
>
> You can have tileindex in different projection and it can contain images
> which are originally in several projections nowadays with in MapServer >=
> 6.4. Read http://www.gdal.org/gdaltindex.html and
> http://www.mapserver.org/optimization/tileindex.html
>
>
>
> -Jukka Rahkonen-
>
>
>
> *Lähettäjä:* Pablo Sanfilippo [mailto:sanfilippopablo at gmail.com]
> *Lähetetty:* 11. tammikuuta 2018 17:47
> *Vastaanottaja:* Rahkonen Jukka (MML) <jukka.rahkonen at maanmittauslaitos.fi
> >
> *Kopio:* Seth G <sethg at geographika.co.uk>; mapserver-users at lists.osgeo.org
>
> *Aihe:* Re: [mapserver-users] MapServer returns a blank image when
> requesting a square image
>
>
>
> I'm going to try and make that zip.
>
>
>
> About explicit PROJECTION blocks, actually yes. I forgot about mentioning
> that. It works fine when explicitly setting the PROJECTION in the raster
> layer. However, I can't do that because the files referenced by the
> tileindex are in different projections.
>
>
>
> On Thu, Jan 11, 2018 at 11:00 AM, Rahkonen Jukka (MML) <jukka.rahkonen@
> maanmittauslaitos.fi> wrote:
>
> Hi,
>
>
>
> I have been using a spatialite layer as a tileindex for years without
> problems so definitely that is not a bug that affects all users and use
> cases. Try to create a zip file that contains everything that is needed for
> reproducing the issue. Let’s hope that you can make it with a spatialite
> database and two images in the tileindex.
>
>
>
> Have you already tried to add explicit PROJECTION blocks into both LAYERs?
>
>
>
> -Jukka Rahkonen-
>
>
>
>
>
>
>
> *Lähettäjä:* mapserver-users [mailto:mapserver-users-
> bounces at lists.osgeo.org] *Puolesta *Pablo Sanfilippo
> *Lähetetty:* 11. tammikuuta 2018 14:46
> *Vastaanottaja:* Seth G <sethg at geographika.co.uk>
> *Kopio:* mapserver-users at lists.osgeo.org
> *Aihe:* Re: [mapserver-users] MapServer returns a blank image when
> requesting a square image
>
>
>
> Oh, so this is a definitely a bug. Is it reported yet in the issue tracker?
>
>
>
> On Wed, Jan 10, 2018 at 3:55 PM, Seth G <sethg at geographika.co.uk> wrote:
>
> Hi Pablo,
>
>
>
> Just to note I also ran into this issue so you are not alone!
>
> A WMS request from OpenLayers to MapServer would be fine, but modifying
> the size of the image (WIDTH and HEIGHT parameters) would result in a blank
> image and no errors in the logs.
>
> I never got a chance to debug further though. An error should ideally be
> reported somewhere rather than a blank, seemingly valid, image.
>
>
>
> Seth
>
>
>
> --
>
> web:http://geographika.co.uk
>
> twitter: @geographika
>
>
>
>
>
> On Wed, Jan 10, 2018, at 6:46 PM, Pablo Sanfilippo wrote:
>
> Hi all,
>
>
>
> I admit this is the weirdest issue I have come across. This are the
> relevant parts of my MapServer configuration:
>
>
>
> # A valid mapfile used for testing
>
> MAP
>
>   NAME valid
>
>   STATUS ON
>
>   PROJECTION
>
>     "init=epsg:4326"
>
>   END
>
>
>
>   IMAGECOLOR 0 0 0
>
>   TRANSPARENT ON
>
>
>
>   WEB
>
>     METADATA
>
>       "wms_srs"             "EPSG:4326 EPSG:3857"
>
>   END
>
>   END
>
>
>
>   LAYER
>
>     NAME "index"
>
>     STATUS ON
>
>     TYPE POLYGON
>
>     CONNECTIONTYPE POSTGIS
>
>     CONNECTION "host=x port=x dbname=x user=x password=x"
>
>     DATA "geometry from (select i.geometry, i.id, '/vsis3/' ||
> i.s3_bucket || '/' || i.s3_key as location from images_image) as index
> using unique id"
>
>     CLASS
>
>       STYLE
>
>         OUTLINECOLOR 0 0 0
>
>         WIDTH 1.0
>
>         COLOR 200 200 200
>
>         ANTIALIAS true
>
>       END
>
>     END
>
>   END
>
>
>
>   LAYER
>
>     NAME "images"
>
>     STATUS ON
>
>     TILEINDEX "index"
>
>     TILEITEM "location"
>
>     TYPE RASTER
>
>     PROJECTION
>
>       AUTO
>
>     END
>
>     METADATA
>
>       "wms_title"           "Images"
>
>     END
>
>   END
>
>
>
>
>
> END
>
>
>
> The data in the PostGIS index is in EPSG:4326. The images referenced by
> the index are GeoTIFFs georeferenced in EPSG:4326.
>
>
>
> A WMS request for the index layer shows the index polygons fine, whatever
> the SRS and image size in the request.
>
> A WMS request for the images layer using SRS=EPSG:4326 shows the images
> fine, whatever the image size.
>
> A WMS request for the images layer using SRS=EPSG:3857 will work fine as
> long as the requested image size's x is greater than or equal to the y. If
> not, it will return a blank (transparent) image. For example, a 1300x1299
> image will work fine, a 1300x1300 image won't work and 1301x1300 won't work
> either.
>
>
>
> Any clues?
>
>
>
> Thanks!
>
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>
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>
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>
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>
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>
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