ensure that tile source data is not null
ensure that tile source data is not null

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