For use with Minecraft Overviewer. This method will look for "#tags" in your in-game signs. For example: "Here is my chest full of #gold." This will populate your Minecraft overviewer.py map with a gold.png.

Minecraft Overviewer Hash Tag Marker

def customSignFilter(poi):
    import re
    if poi['id'] == 'Sign':
        text_list = [poi['Text1'], poi['Text2'], poi['Text3'], poi['Text4']]
        tag = None
        for i in range(0,len(text_list)):
            if text_list[i].find("#") > -1:
                text_trunc = text_list[i][text_list[i].find("#"):len(text_list[i])]
                if text_trunc.find(" ") > -1:
                    tag = str(text_trunc[1:text_trunc.find(" ")]).lower()
                else:
                    tag = str(text_trunc[1:len(text_trunc)]).lower()
                tag = re.sub(r'[^\w\\/@+\-:,|#]+', '', tag)
        if tag != None and tag != "" and tag != " ":
            poi['icon'] = "icons/"+tag+".png"
            return "\n".join(text_list)