This presumes you know about the security implications of having pages served from you home dir and have taken appropriate precautions to stop unauthorized access:

# add a new directory section to apache

sudo vi /etc/apache2/sites-enabled/000-default

Alias /mapp/ "/home/userme/maps/mapp/"

        Options Indexes MultiViews FollowSymLinks
        AllowOverride All # important to allow .htaccess
        Order deny,allow
        Deny from all
        Allow from 127.0.0.0/255.0.0.0 ::1/128 10.254.239.0/255.255.255.0

# enable mod rewrite in apache

 sudo a2enmod rewrite  && sudo service apache2 restart

# edit the CakePHP access files so they do sensible rewriting.

.htaccess located in Cake Root which in my setup it is /home/userme/maps/mapp/ (this is the directory inside which the CakePHP app, plugins & cake directories are)

   RewriteEngine on
   RewriteBase /mapp/ # add this
   RewriteRule    ^$ app/webroot/    [L]
   RewriteRule    (.*) app/webroot/$1 [L]

.htaccess located in CakeRoot/app/

    RewriteEngine on
    RewriteBase  /mapp/ # add this
    RewriteRule    ^$    webroot/    [L]
    RewriteRule    (.*) webroot/$1    [L]
 

.htaccess located in CakeRoot/app/webroot/

    RewriteEngine On
    RewriteBase /mapp/ #add this
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteRule ^(.*)$ index.php?url=$1 [QSA,L]

# remember to restart apache
sudo service apache2 restart

BTW: The above is available in the _very_ good CakePHP Documentation