Today, as the U.S. cel­e­brates the “nation’s birth­day,” we also round the cor­ner of the 150th anniver­sary of Get­tys­burg, the blood­i­est and arguably most deci­sive bat­tle of an inter­nal strug­gle that nev­er ceas­es to haunt the nation­al psy­che. With over 50,000 Union and Con­fed­er­ate sol­diers killed, injured, gone miss­ing, or cap­tured dur­ing the days of July 1–3, 1863, his­to­ri­ans con­tin­ue to pore over the most minute details of the bat­tle strate­gies of Gen­er­als Lee and Meade. Today’s dig­i­tal imag­ing and satel­lite tech­nol­o­gy means that our views of the action are in many ways far supe­ri­or to any­thing com­man­ders on the field could have hoped for.

Since 2000, the Nation­al Park Ser­vice has used mil­i­tary engi­neer­ing tech­niques to restore the his­toric bat­tle­field to some­thing resem­bling its 1863 state, and, in the past few years, car­tog­ra­phers and researchers Anne Kel­ly Knowles, Dan Miller, Alex Tait, and Allen Car­roll have ana­lyzed new and old maps of the Penn­syl­va­nia ter­rain in and around Get­tys­burg to get a renewed appre­ci­a­tion for what the gen­er­als could and could not see dur­ing the con­flict. Con­fed­er­ate offi­cers had their views obstruct­ed not only by lim­it­ed map­ping tech­nol­o­gy and rel­a­tive field posi­tions, but also by their own com­mu­ni­ca­tion fail­ures. As Knowles points out at the Smithsonian’s web­site:

We know that Con­fed­er­ate gen­er­al Robert E. Lee was vir­tu­al­ly blind at Get­tys­burg, as his for­mer­ly bril­liant cav­al­ry leader J.E.B. Stu­art failed to inform him of Fed­er­al posi­tions, and Con­fed­er­ate scouts’ recon­nais­sance was poor. The Con­fed­er­ates’ field posi­tions, gen­er­al­ly on low­er ground than Yan­kee posi­tions, fur­ther put Lee at a dis­ad­van­tage. A strik­ing con­trast in visu­al per­cep­tion came when Union Gen. Gou­vernour K. War­ren spot­ted Con­fed­er­ate troops from Lit­tle Round Top and called in rein­force­ments just in time to save the Fed­er­al line.

Using so-called GIS (Geo­graph­ic Infor­ma­tion Sys­tems), Knowles and her team are able to show what was hid­den from the sol­ders’ views dur­ing such key moments as Pickett’s Charge. The team used sev­er­al peri­od maps, like the 1863 “iso­met­ri­cal draw­ing” at the top, in their recon­struc­tions. They also used satel­lite images from NASA, includ­ing the May 2013 pic­ture below from the Oper­a­tional Land Imager (OLI). You can see Knowles and her team’s painstak­ing geo­graph­i­cal and topo­graph­ic recon­struc­tions of the coun­try’s costli­est rift at the Smith­son­ian Magazine’s site.

Relat­ed Con­tent:

Hiroshi­ma Atom­ic Bomb­ing Remem­bered with Google Earth

The Get­tys­burg Address Ani­mat­ed

Behold Charles Laughton Deliv­er­ing the Get­tys­burg Address in its Entire­ty in Rug­gles of Red Gap

Josh Jones is a writer and musi­cian based in Wash­ing­ton, DC. Fol­low him at @jdmagness

Dou­glas Engel­bart, a tech­nol­o­gy pio­neer best known for his inven­tion of the com­put­er mouse, died in Ather­ton, Cal­i­for­nia on Wednes­day. He was 88 years old. Engel­bart began work­ing at the Stan­ford Research Insti­tute (SRI Inter­na­tion­al) in 1957, and there, accord­ing to John Markof­f’s obit­u­ary in The New York Times, he began try­ing to make the com­put­er screen “a work­sta­tion that would orga­nize all the infor­ma­tion and com­mu­ni­ca­tions for a giv­en project.” It’s a con­cept we take for grant­ed today. But it was con­sid­ered far-fetched back then. A decade lat­er, Engel­bart brought us all into the world of inter­ac­tive com­put­ing and graph­ic inter­faces when, in 1968, he pre­sent­ed what’s now called “The Moth­er of All Demos.” You can watch it in its entire­ty above. Stan­ford’s Mous­eSite sets the stage for what you’re going to see:

On Decem­ber 9, 1968, Dou­glas C. Engel­bart and the group of 17 researchers work­ing with him in the Aug­men­ta­tion Research Cen­ter at Stan­ford Research Insti­tute in Men­lo Park, CA, pre­sent­ed a 90-minute live pub­lic demon­stra­tion of the online sys­tem, NLS, they had been work­ing on since 1962. The pub­lic pre­sen­ta­tion was a ses­sion of the Fall Joint Com­put­er Con­fer­ence held at the Con­ven­tion Cen­ter in San Fran­cis­co, and it was attend­ed by about 1,000 com­put­er pro­fes­sion­als. This was the pub­lic debut of the com­put­er mouse. But the mouse was only one of many inno­va­tions demon­strat­ed that day, includ­ing hyper­text, object address­ing and dynam­ic file link­ing, as well as shared-screen col­lab­o­ra­tion involv­ing two per­sons at dif­fer­ent sites com­mu­ni­cat­ing over a net­work with audio and video inter­face.

If you want to get right to the action, you can watch the sec­tion where Engel­bart demos the mouse here, plus see pic­tures of his orig­i­nal mouse here. Through the links below, you can relive oth­er great moments in com­put­ing his­to­ry.

Relat­ed Con­tent:

Pong, 1969: A Mile­stone in Video Game His­to­ry

The First 3D Dig­i­tal Film Cre­at­ed by Ed Cat­mull, Co-Founder of Pixar (1970)

The First Piz­za Ordered by Com­put­er, 1974

Steve Jobs Demos the First Mac­in­tosh in 1984

Watch the World’s Old­est Work­ing Dig­i­tal Com­put­er — the 1951 Har­well Deka­tron — Get Fired Up Again