Bridge is not exact in its sorting of orientation or aspect ratio.

@cody_1793 – I also consider this a bug, the file can only be one of three orientations at a time: Portrait, Landscape or Square.

Bug reports are still handled at a separate site for Bridge (requiring a separate user account):

https://adobebridge.uservoice.com/forums/905377-report-bugs

@ExUSA – Thank you for posting a scripted solution!

This feature is not available, but you can work around it by determining the aspect ratio with a script and assigning keywords to mark files.

Save this script as plain text with a .jsx file extension and place in the Bridge Scripts folder. Run this on selected files then filter by keyword.

#target bridge
    if(BridgeTalk.appName == 'bridge'){
        try{
            var ratioCmd = MenuElement.create('command', 'Set Ratio Keyword', 'at the end of Tools'); //create new menu command
            ratioCmd.onSelect = function(){
                Main();
                }
            function Main(){
                try{
                    if(ExternalObject.AdobeXMPScript == undefined) ExternalObject.AdobeXMPScript = new ExternalObject('lib:AdobeXMPScript'); //load xmp library
                    if(app.document.selectionsLength == 0){ //check for selection
                        return;
                        }
                    var thumbs = app.document.selections;
                    var kw1 = '1 to 1'; //new keywords
                    var kw2 = 'Not 1 to 1';
                    var wd = 0;
                    var ht = 0;
                    var ratio = 0;
                    var md = null;
                    var xmp = '';
                    var updatedPacket = '';
                    var i = 0;
                    for(i = 0; i < app.document.selectionsLength; i++){ //loop through selections
                        if(thumbs[i].hasMetadata){ //image file with metadata
                            md = thumbs[i].synchronousMetadata; //get metadata
                            xmp = new XMPMeta(md.serialize());
                            wd = thumbs[i].core.quickMetadata.width; //get dimensions
                            ht = thumbs[i].core.quickMetadata.height;
                            ratio = wd / ht; //determine ratio
                            if(ratio == 1){
                                xmp.appendArrayItem(XMPConst.NS_DC, 'subject', kw1, 0,XMPConst.PROP_IS_ARRAY); //add keyword
                                }
                            else{
                                xmp.appendArrayItem(XMPConst.NS_DC, 'subject', kw2, 0,XMPConst.PROP_IS_ARRAY);
                                }
                            updatedPacket = xmp.serialize(XMPConst.SERIALIZE_OMIT_PACKET_WRAPPER | XMPConst.SERIALIZE_USE_COMPACT_FORMAT);
                            thumbs[i].metadata = new Metadata(updatedPacket); //update metadata
                            }
                        }
                    }
                catch(e){
                    Window.alert(e + ' ' + e.line); //error
                    }
                }
            }
        catch(e){
            Window.alert(e + ' ' + e.line);
            }
        }