It is certainly possible to get negative values when smoothing, especially on the edges. But we cannot reproduce your problem because you did not provide any code.
-roger Oarabile Molaodi wrote: > I want to do kernel smoothing on the standardised mortality rates at > specified location(x-y coordinates) and be able to produce contour map. > I've tried to use the package called fields in R (function smooth.2d) > but the problem is I get negative results after smoothing and I do not > understand why? Your contributions will be highly appreciated or if > there is any package that can do this I will be happy to know about it. > Thanks in advance for your comments. > Oarabile > > Below is how my data in R looks like > Xcoord Ycoord smr > 1 383894.70 653202.8 1.5816327 > 2 339053.00 631770.9 1.0003473 > 3 369164.50 609973.2 1.2943872 > 4 313477.70 640382.8 0.9443508 > 5 290748.80 695088.8 1.1662125 > 6 287547.50 679829.6 0.9433962 > 7 259031.90 704478.3 1.0184905 > 8 329107.60 585753.3 1.0445860 > 9 292170.20 578978.2 1.1287758 > 10 268330.90 564281.7 0.9805996 > 11 227395.50 561524.6 1.1947431 > 12 310130.70 689395.0 1.0991957 > 13 325756.00 696565.6 1.1734694 > 14 339427.20 713217.2 0.8724100 > 15 391752.10 805661.5 1.2483221 > 16 385935.90 851044.5 1.0558140 > 17 372471.20 826373.7 1.4220183 > 18 354901.70 791107.2 0.9175084 > 19 324944.10 842040.8 1.0447080 > 20 275672.50 802570.4 0.9899329 > 21 320750.00 954769.7 1.0866834 > 22 243489.20 832748.8 1.0995658 > 23 166559.70 786365.3 1.0401267 > 24 288160.80 846054.4 1.0299003 > 25 220347.00 869181.0 0.9529435 > 26 175863.63 822593.9 0.9902252 > 27 246114.40 938419.3 0.8909370 > 28 359070.60 669738.3 0.9883721 > 29 320614.70 670434.2 1.1288534 > 30 331414.80 659972.3 0.9070866 > 31 299336.90 666122.9 0.7969349 > 32 156965.25 708047.7 1.1410460 > 33 253867.30 674916.5 0.9256710 > 34 249188.40 674272.8 1.0869565 > 35 272463.00 679495.3 0.8576698 > 36 252643.80 611378.4 0.8615611 > 37 212637.35 643725.0 0.8596604 > 38 234751.95 691803.4 0.9706546 > 39 264856.20 644684.8 0.8468395 > 40 253949.30 653042.5 0.8106169 > 41 260412.35 663552.2 0.9253686 > 42 270807.60 657454.0 0.9002826 > 43 228477.30 670443.2 1.0782502 > 44 248215.30 641897.3 0.9240407 > 45 229797.50 596059.0 1.1579197 > 46 291725.00 635771.8 0.8908766 > 47 278012.80 667982.0 1.0240000 > 48 279490.80 659761.6 0.9828301 > 49 242791.70 662651.8 1.0230584 > 50 263217.20 675295.2 0.9759817 > 51 341138.80 754471.3 0.9505541 > 52 334963.00 735075.4 0.9264498 > 53 286139.70 733611.6 0.9052453 > 54 354015.60 1025696.8 0.8905506 > 55 455775.60 1201636.0 1.0862620 > 56 88429.32 854994.4 0.9577015 > > ______________________________________________ > [email protected] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html > ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
