[MapServer-users] Wrong and inconsistent GetFeatureInfo result for CLUSTER layer

Tue Mar 4 00:14:13 PST 2025

So, I've now confirmed that version 8.4 behaves the same way. Since I can't seem to find a solution for this, and because it appears to be a bug, I think I should create an issue.

Erik

Fra: MapServer-users <mapserver-users-bounces at lists.osgeo.org<mailto:mapserver-users-bounces at lists.osgeo.org>> På vegne av Guldberg, Erik via MapServer-users
Sendt: tirsdag 18. februar 2025 12:37
Til: Seth G <sethg at geographika.co.uk<mailto:sethg at geographika.co.uk>>
Kopi: MapServer Users <mapserver-users at lists.osgeo.org<mailto:mapserver-users at lists.osgeo.org>>
Emne: Re: [MapServer-users] Wrong and inconsistent GetFeatureInfo result for CLUSTER layer

Hi,
I may try to see if I manage to get a v. 8.4 up and running, but as I read the issues that were fixed, it's quite another problem, related to the getCapabilities output. I haven't noticed that I have any such problems.

Erik

Fra: Seth G <sethg at geographika.co.uk<mailto:sethg at geographika.co.uk>>
Sendt: tirsdag 18. februar 2025 11:04
Til: Guldberg, Erik <Erik.Guldberg at ra.no<mailto:Erik.Guldberg at ra.no>>; MapServer Users <mapserver-users at lists.osgeo.org<mailto:mapserver-users at lists.osgeo.org>>
Emne: Re: [MapServer-users] Wrong and inconsistent GetFeatureInfo result for CLUSTER layer

Hi Erik,

Are you able to confirm the issue still exists on newer versions of MapServer (8.4 or 8.2.2)?
There was a fix related to CLUSTER and PostGIS added to the newer versions, see https://github.com/MapServer/MapServer/pull/7111.

Seth

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web:https://geographika.net & https://mapserverstudio.net
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On Tue, Feb 18, 2025, at 10:16 AM, Guldberg, Erik via MapServer-users wrote:

It's interesting to note that, if I set a label, like the name of the object ("tittel"), it's always correct. It's only the getFeatureInfo that is wrong.

Also, I've tried to create a cluster layer from another dataset, where the main different is, I believe, that the projection is different, and I don't have the same problem there. Using the same cluster settings.

Fra: MapServer-users <mapserver-users-bounces at lists.osgeo.org<mailto:mapserver-users-bounces at lists.osgeo.org>> På vegne av Guldberg, Erik via MapServer-users
Sendt: fredag 14. februar 2025 14:51
Til: mapserver-users at lists.osgeo.org<mailto:mapserver-users at lists.osgeo.org>
Emne: [MapServer-users] Wrong and inconsistent GetFeatureInfo result for CLUSTER layer

Hi,

I have a WMS service, https://kart.ra.no/wms/brukerminner, where I have problems getting correct getFeatureInfo results from a layer with CLUSTER content.

It contains the cluster layer and a regular point layer for the same data. The regular point layer is shown at 1:50 000.

For single objects in both the cluster layer, I want to be able to use getFeatureInfo. This works, but the problem is that the results most of the time are wrong, and that they change for time to time, likely due to change in zoom level. For the regular point layer, the result is always correct. I've also created a test cluster layer without the scale limit, and that also gives the correct result if I zoom in enough.

All the symbols are placed correctly in the map, for all layers. I've used the database, and also this OGC API service (that uses the same data source as the WMS) as a reference: https://api.ra.no/brukerminner

I'm using MapServer version 7.6.4.

Some example queries, using QGIS.

Wrong result. The object I get in the getfeatureinfo is 64 km away from where I clicked.

https://kart.ra.no/wms/brukerminner?language=nor&SERVICE=WMS&VERSION=1.3.0&REQUEST=GetFeatureInfo&BBOX=760392.02671199827454984%2C8263040.88853696268051863%2C1033357.36004533339291811%2C8407916.1385369636118412&CRS=EPSG%3A3857&WIDTH=1984&HEIGHT=1053&LAYERS=Brukerminner&STYLES=&FORMAT=image%2Fpng&QUERY_LAYERS=Brukerminner&INFO_FORMAT=text%2Fhtml&I=1069&J=616&FEATURE_COUNT=10

Zoomed in a bit more gives another, wrong result. This is 8.7 km away from where I clicked:

https://kart.ra.no/wms/brukerminner?language=nor&SERVICE=WMS&VERSION=1.3.0&REQUEST=GetFeatureInfo&BBOX=871972.11004533257801086%2C8307721.07603696547448635%2C940213.44337866583373398%2C8343939.88853696547448635&CRS=EPSG%3A3857&WIDTH=1984&HEIGHT=1053&LAYERS=Brukerminner&STYLES=&FORMAT=image%2Fpng&QUERY_LAYERS=Brukerminner&INFO_FORMAT=text%2Fhtml&I=1022&J=627&FEATURE_COUNT=10

This is the Test-layer, how it looks now. I've tried different variations of PROCESSING settings.

LAYER

                NAME "TEST"

                DEBUG 5

                TYPE POINT

                STATUS ON

                TEMPLATE "../templates/brukerminner.html"

                HEADER "../templates/header.html"

                FOOTER "../templates/footer.html"

    TOLERANCEUNITS pixels

                TOLERANCE 25

    # MINSCALEDENOM 50000

                METADATA

                               "wms_enable_request" "*"

        "wms_include_items" "tittel"

        "wms_title" "TEST"

                               "wms_feature_info_mime_type" "text/html"

END

PROJECTION

                "init=epsg:4326"

END

EXTENT -19.76 54.57 45.57 82.67  #4326

PROCESSING "CLOSE_CONNECTION=DEFER"

CONNECTIONTYPE POSTGIS

CONNECTION "host=host  dbname=db user=user password=password port=5432"

DATA "geom from xx.xx using unique id using srid=4326"

LABELITEM "Cluster_FeatureCount"

# PROCESSING "CLUSTER_ALGORITHM=SIMPLE"

PROCESSING "CLUSTER_GET_ALL_SHAPES=ON"

PROCESSING "ITEMS=tittel,beskrivelse,fylke,kommune,opprettet,endret,opprettet_av,linkkulturminnesok,gpsposisjon"

# PROCESSING "CLUSTER_KEEP_LOCATIONS=ON"

CLUSTER

MAXDISTANCE 50

REGION "ellipse"

END

CLASS

                NAME "Brukerminne"

    EXPRESSION ("[Cluster_FeatureCount]" = "1")

                STYLE

                               SYMBOL "brukerminne"

        COLOR 200 0 0

                               SIZE 27

        OFFSET 0 -13.5

                END

END

END

Anyone with ideas on what's wrong?

Thanks,

Erik

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