I seem to be having problems finding that map on any official sites - perhaps the OP could post the PEW site it came from.
Mexican Immigrants in the United States | migrationpolicy.org
Funny, I have trouble taking a George Soros funded organization seriously
1400 16th Street NW - Suite 300
Washington, DC
20036
Phone

202) 266-1940
Fax

202) 266-1900
Email :
Communications@migrationpolicy.org
URL: Website
Migration Policy Institute (MPI)'s Visual Map
Seeks the dissolution of U.S. borders, and the legalization of illegal immigrants currently residing in America
Works closely with the National Council of La Raza and the American Civil Liberties Union
The Migration Policy Institute (MPI) describes itself as an independent, nonpartisan, nonprofit think tank
dedicated to analysis of the movement of people worldwide, whether their relocations are voluntary or forced, and whether they occur at the local, national, or international levels.
MPI was established in 2001 by Kathleen Newland (a former senior associate at the Carnegie Endowment for International Peace) and Demetrios Papademetriou (former director for immigration policy and research in President Bill Clinton's Labor Department), when the Carnegie Endowment's International Migration Policy Program (IMPP) became an independent entity. IMPP was known for conducting migration policy briefings and roundtables, luncheon seminars, and study advisory groups aimed at influencing legislators and program officials in Washington.
MPI has continued its predecessors tradition by supporting: (a) self-governance for communities that straddle the U.S./Mexico border, rather than strict obedience to immigration policies set in Washington; (b) a more permissive U.S. refugee admissions and resettlement policy; (c) increased social-welfare benefits for illegal immigrants residing in the U.S.; (d) a movement beyond absolute notions of [national] sovereignty; (e) the re-conceptualization of the common border and the border region as a line of convergence rather than separation; and (f) the creation of a North America with gradually disappearing border controls.