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"# hist039_TH2Poly_usa\n",
"bins (TH2Poly), fill it and draw it using the `col` option. The initial data\n",
"are stored in TMultiGraphs. They represent the USA map. Such histograms can\n",
"be rendered in 3D using the option `legogl`.\n",
"\n",
"The initial data have been downloaded from: http://www.maproom.psu.edu/dcw/\n",
"This database was developed in 1991/1992 and national boundaries reflect\n",
"political reality as of that time.\n",
"\n",
"\n",
"\n",
"\n",
"**Author:** Olivier Couet \n",
"This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Tuesday, May 19, 2026 at 08:12 PM."
]
},
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"id": "157a9f88",
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"shell.execute_reply": "2026-05-19T20:12:54.348233Z"
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"outputs": [
{
"name": "stderr",
"output_type": "stream",
"text": [
"[TFile::Cp] Total 0.95 MB\t|>...................| 0.00 % [0.0 MB/s]\r",
"[TFile::Cp] Total 0.95 MB\t|====================| 100.00 % [59.1 MB/s]\r\n"
]
}
],
"source": [
"Int_t i, bin;\n",
"const Int_t nx = 48;\n",
"const char *states[nx] = {\n",
" \"alabama\", \"arizona\", \"arkansas\", \"california\", \"colorado\", \"connecticut\", \"delaware\",\n",
" \"florida\", \"georgia\", \"idaho\", \"illinois\", \"indiana\", \"iowa\", \"kansas\",\n",
" \"kentucky\", \"louisiana\", \"maine\", \"maryland\", \"massachusetts\", \"michigan\", \"minnesota\",\n",
" \"mississippi\", \"missouri\", \"montana\", \"nebraska\", \"nevada\", \"new_hampshire\", \"new_jersey\",\n",
" \"new_mexico\", \"new_york\", \"north_carolina\", \"north_dakota\", \"ohio\", \"oklahoma\", \"oregon\",\n",
" \"pennsylvania\", \"rhode_island\", \"south_carolina\", \"south_dakota\", \"tennessee\", \"texas\", \"utah\",\n",
" \"vermont\", \"virginia\", \"washington\", \"west_virginia\", \"wisconsin\", \"wyoming\"};\n",
"Double_t pop[nx] = {4708708, 6595778, 2889450, 36961664, 5024748, 3518288, 885122, 18537969, 9829211, 1545801,\n",
" 12910409, 6423113, 3007856, 2818747, 4314113, 4492076, 1318301, 5699478, 6593587, 9969727,\n",
" 5266214, 2951996, 5987580, 974989, 1796619, 2643085, 1324575, 8707739, 2009671, 19541453,\n",
" 9380884, 646844, 11542645, 3687050, 3825657, 12604767, 1053209, 4561242, 812383, 6296254,\n",
" 24782302, 2784572, 621760, 7882590, 6664195, 1819777, 5654774, 544270};\n",
"\n",
"auto usa = new TCanvas(\"USA\", \"USA\");\n",
"usa->ToggleEventStatus();\n",
"Double_t lon1 = -130;\n",
"Double_t lon2 = -65;\n",
"Double_t lat1 = 24;\n",
"Double_t lat2 = 50;\n",
"auto p = new TH2Poly(\"Lower48\", \"Lower 48 Population (2009);Latitude;Longitude\", lon1, lon2, lat1, lat2);\n",
"\n",
"const auto fileName = \"usa.root\";\n",
"const auto fileNameUrl = \"http://root.cern/files/usa.root\";\n",
"if(gSystem->AccessPathName(fileName))\n",
" TFile::Cp(fileNameUrl, fileName);\n",
"\n",
"auto f = TFile::Open(fileName);\n",
"\n",
"if (!f) {\n",
" printf(\"Cannot access %s. Is internet working ?\\n\", fileName);\n",
" return;\n",
"}"
]
},
{
"cell_type": "markdown",
"id": "de944621",
"metadata": {},
"source": [
"Define the TH2Poly bins."
]
},
{
"cell_type": "code",
"execution_count": 2,
"id": "99c56a8e",
"metadata": {
"collapsed": false,
"execution": {
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"outputs": [],
"source": [
"TMultiGraph *mg;\n",
"TKey *key;\n",
"TIter nextkey(gDirectory->GetListOfKeys());\n",
"while ((key = (TKey *)nextkey())) {\n",
" TObject *obj = key->ReadObj();\n",
" if (obj->InheritsFrom(\"TMultiGraph\")) {\n",
" mg = (TMultiGraph *)obj;\n",
" bin = p->AddBin(mg);\n",
" }\n",
"}"
]
},
{
"cell_type": "markdown",
"id": "b875838a",
"metadata": {},
"source": [
"Fill TH2Poly, with capital letters for the states names"
]
},
{
"cell_type": "code",
"execution_count": 3,
"id": "3d6d3afb",
"metadata": {
"collapsed": false,
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"shell.execute_reply": "2026-05-19T20:12:54.934327Z"
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"text/html": [
"\n",
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"source": [
"for (i = 0; i < nx; i++)\n",
" p->Fill(states[i], pop[i]);\n",
"\n",
"gStyle->SetOptStat(0);\n",
"p->Draw(\"colz textn\");"
]
},
{
"cell_type": "markdown",
"id": "8bce7994",
"metadata": {},
"source": [
"Add the reference for the population"
]
},
{
"cell_type": "code",
"execution_count": 4,
"id": "8258536f",
"metadata": {
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"shell.execute_reply": "2026-05-19T20:12:55.139505Z"
}
},
"outputs": [],
"source": [
"TLatex pupulationRef(-128, 27, \"#scale[.55]{#splitline{Source:}{http://eadiv.state.wy.us/pop/st-09est.htm}}\");\n",
"pupulationRef.DrawClone();"
]
},
{
"cell_type": "markdown",
"id": "69ebdc08",
"metadata": {},
"source": [
"Draw all canvases "
]
},
{
"cell_type": "code",
"execution_count": 5,
"id": "09e2ce9a",
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"collapsed": false,
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],
"source": [
"%jsroot on\n",
"gROOT->GetListOfCanvases()->Draw()"
]
}
],
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