[Geomoose-users] GeoMoose 3 - AGS Legend Support

Fri Jun 12 12:50:38 PDT 2020

I think you are basically correct.  A couple of minor points:

Keep in mind that the legend graphic file could be any URL that returns an image and doesn't necessarily need to point to a static file on the web server.  So, for example, it could be a legend or preview imaged generated from a WMS request (or other URL). However, I suspect that you are correct that it will be 'static' as in it will only be loaded once per GeoMoose session rather than updated as the map view changes.

Also, an HTML legend can be all sorts of creative with what is included (<a>, CSS background-image: url(...), etc.).

The layer types 'mapserver' and 'mapserver-wfs' are just shortcuts for 'wms' and 'wfs' where GeoMoose does the url='/cgi-bin/mapserv?map=<file>&' substitution for you (using the values from config.js).  (Long ago, the 'mapserver' layer type actually made a Mapserver 'mode=map' request, but it has been using WMS behind the scenes since at least GeoMoose 2.6.)

Rant/aside/tangent:

Personally, I don't like the mapserver layer types and think that this path rewrite stuff is better done on the web server so access is consistent with other WxS clients (like QGIS).

I have Apache setup with Actions and RewriteRules so that '/datasets/some.map' -> '/cgi-bin/mapserv' with the MS_MAPFILE environment variable set to '/srv/datasets/some.map' behind the scenes.

This also allows for using Apache to manage access to individual mapfiles as well as separates mapfiles in the logs because every request isn't just /cgi-bin/mapserv with the actual mapfile being potentially hidden in a POST.  This also uses Apache to be sure the .map file exists and is under the /srv/datasets tree before executing the request (so things like '..' in the path don't let people tell mapserver to access other places on your server).

This does require a patch to mapserver or the setting the "ows_onlineresource" metadata in every mapfile so the links in GetCapabilites responses point to the right spot.

Something like:

         <Directory "/usr/lib/cgi-bin">
                 AllowOverride None
                 Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch

                 # Only allow specified CGI-BIN files
                 Require all denied

                 # Mapserver
                 <Files "mapserv">
                         Require all granted

                         SetEnv MS_ERRORFILE "stderr"
                         SetEnv MS_MAP_NO_PATH "true"

                         RewriteEngine on
                         RewriteCond %{env:REDIRECT_HANDLER} ^mapserver
                         RewriteCond %{PATH_INFO} ^/datasets/(.*)
                         RewriteRule .* - [C,env=MS_MAPFILE:/srv/datasets/%1]
                         RewriteRule .* - [L]

                         RewriteRule .* - [F]
                 </Files>
         </Directory>

         <Directory "/srv/datasets/">
                 Require all denied

                 Action mapserver /cgi-bin/mapserv
                 AddHandler mapserver .map
                 <Files "*.map">
                         Require all granted
                 </Files>
         </Directory>
         Alias /datasets/ /srv/datasets/

On 6/12/20 2:05 PM, Brent Fraser wrote:
> So much documenting to do...
>    
>    
>   AFAIK, GM3 has two kinds of legends: static and dynamic (my terms)
>    
>   Static you add to the mapbook for vector layers as type="html" (so you
> code CSS styling in the mapbook), or type="img" and you supply a graphic
> file.
>    
>   Dynamic is only for map-source types of "mapserver" (and maybe "wms"?) and
> the legend will be created on the server composed of the rendered features.
>   I think GM only supports image legends, not JSON ,etc.
>    
>   So currently, GM 3 does not support a dynamic (data server-generated)
> legend for vector data sources.
>    
>   Brent
>    
>    
>   -------- Original Message --------
>> From: "Jim Klassen" <klassen.js at gmail.com>
>> Sent: June 12, 2020 12:37 PM
>> To: geomoose-users at lists.osgeo.org
>> Subject: Re: [Geomoose-users] GeoMoose 3 - AGS Legend Support
>>
>> In GeoMoose, vector layers are styled and rendered in the browser rather
> than by the server. Thus, I would expect legends for ags-vector to behave
> the same as any other vector layer.  If that isn't currently the case for
> ags-vector then that is an oversight/bug. On 6/12/20 1:19 PM, Brent Fraser
> wrote: > Hi Chris, > > I haven't looked into AGS legend yet, but my guess
> is no, neither > type="ags" or type="ags-vector" support legends. > > A
> longer answer: > > Both type="ags" and type="ags-vector" are for accessing
> ArcGIS Servers > with MapServer endpoints (they do not access FeatureServer
> endpoints) > Responding to Legend requests is an option when setting up the
> AGS server > (and it looks like most don't?). And AGS servers can serve
> different > formats of legends >
> (https://developers.arcgis.com/rest/services-reference/legend-map-service-.h
>   > tm) and different kinds >
> https://developers.arcgis.com/rest/services-reference/query-legends-map-serv
>   > ice-.htm). > > > Best Regards, > Brent Fraser > > > -------- Original
> Message -------- >> From: "Christopher Hughes" <chughes at co.lincoln.or.us>
>>> Sent: June 12, 2020 9:20 AM >> To: "GeoMoose Users"
> <geomoose-users at lists.osgeo.org> >> Subject: [Geomoose-users] GeoMoose 3 -
> AGS Legend Support >> >> Is there support for AGS legends in GeoMoose 3?
> Particularly for vector >> layers with multiple classes where the meaning
> of the symbology isn't >> readily >> apparent. >> >> I tried turning on the
> legend for the ags services in the demo > (railroads >> and the Nat Geo
> world map) and was unsuccessful. >> >> Best, >> Chris >> >> -- >> Chris
> Hughes >> >> GIS Analyst >> Lincoln County Surveyor Department >> 880 NE
> 7th St. l Newport, OR 97365 >> Tel: (541) 574 1283 >>
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