modify a_layer by sort_key for overlapping road outlines
modify a_layer by sort_key for overlapping road outlines

zerebubuth/tangram,taylorhxu/tangram,zerebubuth/tangram,taylorhxu/tangram,rosamcgee/tangram,TitoAgudelo/tangram,TitoAgudelo/tangram,ceseale/tangram,TitoAgudelo/tangram,DHaylock/tangram,rosamcgee/tangram,DHaylock/tangram,tangrams/tangram,xvilan/tangram,taylorhxu/tangram,tangrams/tangram,rosamcgee/tangram,xvilan/tangram,ceseale/tangram,DHaylock/tangram,ceseale/tangram,zerebubuth/tangram,xvilan/tangram