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    <p>Hello Seth,</p>
    <p>Thanks for replying. I experimented and found out there's no
      difference if I use something minimal such as what you suggested.
      What does make a difference is the CRS: if I tell QGIS to use
      EPSG:2100 (Greek grid—the CRS the data files use), then everything
      works fine. If I use 4326 or 3857, then the problem appears.
      Therefore it appears that the problem is with reprojecting (as the
      stackexchange user "nmtoken" had suspected). Leaflet seems to be
      requesting 3857.</p>
    <p>What would be the right course of action here? Should I tell
      Leaflet to do the reprojection instead? Should I investigate
      further why mapserver has trouble reprojecting (and how would I do
      that)? Should I reproject my data files (GML) offline and store
      them in 3857 instead of 2100? Is there any common/best practice
      regarding this?</p>
    <p>Thanks!</p>
    <p>Antonis</p>
    <p><br>
    </p>
    <p><br>
    </p>
    On 28/09/2022 17.47, Seth G wrote:<br>
    <blockquote type="cite"
      cite="mid:895e9d3d-cc0e-4a4f-adcd-a76ba66db6c2@app.fastmail.com">
      <meta http-equiv="content-type" content="text/html; charset=UTF-8">
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      <style type="text/css">p.MsoNormal,p.MsoNoSpacing{margin:0}</style>
      <div>Hi,<br>
      </div>
      <div><br>
      </div>
      <div>Is there any change if you update the layer to have a single
        class with a simple line (no EXPRESSION, LABEL, MAXSCALEDENOM)?<br>
      </div>
      <div><br>
      </div>
      <div>E.g.<br>
      </div>
      <div><br>
      </div>
      <div>        CLASS<br>
      </div>
      <div>            STYLE<br>
      </div>
      <div>                COLOR 0 0 255<br>
      </div>
      <div>                WIDTH 6<br>
      </div>
      <div>            END<br>
      </div>
      <div><br>
      </div>
      <div>Seth<br>
      </div>
      <div><br>
      </div>
      <div id="sig62266145">
        <div class="signature">--<br>
        </div>
        <div class="signature">web:<a href="https://geographika.net"
            moz-do-not-send="true" class="moz-txt-link-freetext">https://geographika.net</a><br>
        </div>
        <div class="signature">twitter: @geographika<br>
        </div>
      </div>
      <div><br>
      </div>
      <div>On Wed, Sep 28, 2022, at 1:03 PM, Antonis Christofides wrote:<br>
      </div>
      <blockquote type="cite" id="qt" style="">
        <p>Hello,<br>
        </p>
        <p>I have a problem that has already been discussed in
          stackexchange
          (<a class="qt-moz-txt-link-freetext moz-txt-link-freetext"
href="https://gis.stackexchange.com/questions/440902/mapserver-wms-not-all-features-show-depending-on-how-i-zoom-and-pan"
            moz-do-not-send="true">https://gis.stackexchange.com/questions/440902/mapserver-wms-not-all-features-show-depending-on-how-i-zoom-and-pan</a>),
          but without solution so far.<br>
        </p>
        <p>I'm repeating the full text here, but if there's any problem
          with the images it might be better to go to stackexchange to
          read it.<br>
        </p>
        <p>Here is how QGIS shows an irrigation network, received by
          MapServer via WMS and superimposed on OpenStreetMap:<br>
        </p>
        <p><img src="https://i.stack.imgur.com/bCOib.png" alt="enter
            image description here" moz-do-not-send="true"><br>
        </p>
        <p>Here is the same thing, but slightly panned to the right:<br>
        </p>
        <p><img src="https://i.stack.imgur.com/Ca7Tc.png" alt="enter
            image description here" moz-do-not-send="true"><br>
        </p>
        <p>Several items are obviously missing. In fact there are items
          missing in the top picture as well. Different items become
          visible as I zoom and pan differently.<br>
        </p>
        <p>Since this pretty much tells the whole story, I'm not going
          into more details. MapServer version is 7.6.2 (prepackaged for
          Debian). The base URL is <a class="qt-moz-txt-link-freetext
            moz-txt-link-freetext"
href="https://poros.irmasys.com/cgi-bin/mapserv?map=/opt/aira-poros/aira-poros/mapserver/extralayers.map"
            moz-do-not-send="true">https://poros.irmasys.com/cgi-bin/mapserv?map=/opt/aira-poros/aira-poros/mapserver/extralayers.map</a>.
          Finally, below I paste the interesting parts of the mapfile.<br>
        </p>
        <p>Thanks!<br>
        </p>
        <p>Antonis<br>
        </p>
        <p><br>
        </p>
        <p><br>
        </p>
        <div><br>
        </div>
        <pre><code>MAP
    NAME "aira-poros"
    STATUS ON
    SIZE 9040 7731
    EXTENT 103986.57 3850796.18 1007945.14 4623933.00
    UNITS meters
    PROJECTION
        "init=epsg:2100"
    END
    CONFIG MS_ERRORFILE "/var/log/mapserver/extralayers.log"

    # [Omitting some OUTPUTFORMAT sections]

    WEB
        IMAGEPATH "/var/cache/mapserver/"
        IMAGEURL "/mapserver_tmp/"
        METADATA
            "wms_title" "Aira Poros"
            "wms_onlineresource" <a class="qt-moz-txt-link-rfc2396E" href="https://poros.irmasys.com/cgi-bin/mapserv?map=/opt/aira-poros/aira-poros/mapserver/extralayers.map&" moz-do-not-send="true">"https://poros.irmasys.com/cgi-bin/mapserv?map=/opt/aira-poros/aira-poros/mapserver/extralayers.map&"</a>
            "wms_srs" "EPSG:4326 EPSG:2100 EPSG:3857"
            "wms_enable_request" "*"
            "wms_feature_info_mime_type" "text/html"

            "wfs_title" "Aira Poros"
            "wfs_onlineresource" <a class="qt-moz-txt-link-rfc2396E" href="https://poros.irmasys.com/cgi-bin/mapserv?map=/opt/aira-poros/aira-poros/mapserver/extralayers.map&" moz-do-not-send="true">"https://poros.irmasys.com/cgi-bin/mapserv?map=/opt/aira-poros/aira-poros/mapserver/extralayers.map&"</a>
            "wfs_srs" "EPSG:2100 EPSG:4326 EPSG:3857"
            "wfs_enable_request" "*"
        END
    END

    LAYER
        NAME "irrigation-network" 
        TYPE LINE
        CONNECTIONTYPE OGR
        CONNECTION "irrigation-network.gml"
        METADATA
            "wms_title" "Irrigation network"
            "wfs_title" "Irrigation network"
            "gml_include_items" "all"
            "gml_featureid" "id"
        END
        STATUS ON
        PROJECTION
            "init=epsg:2100"
        END
        CLASSITEM 'category'
        CLASS
            EXPRESSION '1'
            STYLE
                COLOR 0 0 255
                OPACITY 50
                WIDTH 6
            END
            LABEL
                COLOR 0 0 255
                ANGLE FOLLOW
                OFFSET 5 99
                MAXSCALEDENOM 10000
                TEXT "[irri_code]"
            END
            LABEL
                COLOR 0 0 255
                ANGLE FOLLOW
                OFFSET -8 99
                MAXSCALEDENOM 10000
                EXPRESSION (NOT('[Diameter]' = ''))
                TEXT "D=[Diameter] mm"
            END
        END

        # [Omitting three more classes]
    END

    # [Omitting four more layers]
END</code>
</pre>
        <div>_______________________________________________<br>
        </div>
        <div>MapServer-users mailing list<br>
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        <div><a href="mailto:MapServer-users@lists.osgeo.org"
            moz-do-not-send="true" class="moz-txt-link-freetext">MapServer-users@lists.osgeo.org</a><br>
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        <div><a
            href="https://lists.osgeo.org/mailman/listinfo/mapserver-users"
            moz-do-not-send="true" class="moz-txt-link-freetext">https://lists.osgeo.org/mailman/listinfo/mapserver-users</a><br>
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        </div>
      </blockquote>
      <div><br>
      </div>
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