[MapServer-users] WMS: Not all features show, depending on how I zoom and pan

[Scott]

It would be interesting if you could change your 
'irrigation-network.gml' into a different format, say .shp, something like:

ogr2ogr irrigation-network.shp irrigation-network.gml

Then try that as a data source in your layer and see if your results 
differ. This would might help us distinguish between a driver issue and 
a mapserver issue.



On 10/2/22 04:51, Antonis Christofides wrote:
> Hello Seth,
> 
> 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.
> 
> 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?
> 
> Thanks!
> 
> Antonis
> 
> 
> 
> On 28/09/2022 17.47, Seth G wrote:
>> Hi,
>>
>> Is there any change if you update the layer to have a single class 
>> with a simple line (no EXPRESSION, LABEL, MAXSCALEDENOM)?
>>
>> E.g.
>>
>>         CLASS
>>             STYLE
>>                 COLOR 0 0 255
>>                 WIDTH 6
>>             END
>>
>> Seth
>>
>> --
>> web:https://geographika.net
>> twitter: @geographika
>>
>> On Wed, Sep 28, 2022, at 1:03 PM, Antonis Christofides wrote:
>>>
>>> Hello,
>>>
>>> I have a problem that has already been discussed in stackexchange 
>>> (https://gis.stackexchange.com/questions/440902/mapserver-wms-not-all-features-show-depending-on-how-i-zoom-and-pan <https://gis.stackexchange.com/questions/440902/mapserver-wms-not-all-features-show-depending-on-how-i-zoom-and-pan>), but without solution so far.
>>>
>>> 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.
>>>
>>> Here is how QGIS shows an irrigation network, received by MapServer 
>>> via WMS and superimposed on OpenStreetMap:
>>>
>>> enter image description here
>>>
>>> Here is the same thing, but slightly panned to the right:
>>>
>>> enter image description here
>>>
>>> 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.
>>>
>>> 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 
>>> https://poros.irmasys.com/cgi-bin/mapserv?map=/opt/aira-poros/aira-poros/mapserver/extralayers.map <https://poros.irmasys.com/cgi-bin/mapserv?map=/opt/aira-poros/aira-poros/mapserver/extralayers.map>. Finally, below I paste the interesting parts of the mapfile.
>>>
>>> Thanks!
>>>
>>> Antonis
>>>
>>>
>>>
>>>
>>> |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" 
>>> "https://poros.irmasys.com/cgi-bin/mapserv?map=/opt/aira-poros/aira-poros/mapserver/extralayers.map&" <https://poros.irmasys.com/cgi-bin/mapserv?map=/opt/aira-poros/aira-poros/mapserver/extralayers.map&> "wms_srs" "EPSG:4326 EPSG:2100 EPSG:3857" "wms_enable_request" "*" "wms_feature_info_mime_type" "text/html" "wfs_title" "Aira Poros" "wfs_onlineresource" "https://poros.irmasys.com/cgi-bin/mapserv?map=/opt/aira-poros/aira-poros/mapserver/extralayers.map&" <https://poros.irmasys.com/cgi-bin/mapserv?map=/opt/aira-poros/aira-poros/mapserver/extralayers.map&> "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|
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>>
> 
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