Selected Topics in Archaeology
Selected Topics in Archaeology ANTH 5589
Popular in Course
Popular in anthropology, evolution, sphr
This 5 page Class Notes was uploaded by Laurie Lind on Monday September 21, 2015. The Class Notes belongs to ANTH 5589 at University of Virginia taught by Fraser Neiman in Fall. Since its upload, it has received 62 views. For similar materials see /class/209707/anth-5589-university-of-virginia in anthropology, evolution, sphr at University of Virginia.
Reviews for Selected Topics in Archaeology
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 09/21/15
Spattai Data Anaiysts in Archaeoiogv Anthtupulugy 5th Fraser D Neiman un rsity uf Virginia 219m Spring 2nu7 Kriging Artifact Density Surfaces in ArcGIS 1 The ingredients rAdata le e m dbfur svfmmat quotcuntammgtheuuntsufdd erentamfacttypesm e h duadrat and the nuthmg and eastahg eddrdhates ufthe duadrat centxmds c at e c and ether feature eh Lhe site 2 Bring the data into ArcMap OpmAIEMap 9 AddDataNaixgatetuthe dhfwtthmehurhene data e e Repeat ferth dx 5 3 Create a shape file for the h is of excavation 7N we ereate a shape diethatwtu eehtath the hrmts efexeayaaeh Getthte Ar Tuulbux Right chek en the Felderth wheh yuu Want te stare the shapetne hen gt shapeme gt Polygon Nmextsumehngsensxblewh y LxmnsiufiExczi anu er rm quotes anyway tn the empty shape le quhe same name preeeed as fulluws Right ehek anywhere eh theteed har Make sure Edterrs seteeted eheeked eadaeer gt seare adaeaha Task gt ereaee New Feature rTzrgetshuuld he Limiting xeayataeh d teed rDrawthe pulygun er duuble ehek an the last paint daeer gt dares adaeer gt seep adaeahgnzvsvm Editing liecrewquot Save changes 4 Adding Quadrat Centroids an39stweneedtu addthe centerpumtufeach Excavatan unit erduadrat Thrsrhdermataehrs eehtathed m the data tahte atehg With the smart eeuhts Right ehek er the datatahte and seteetthe Dasplay xy Daea epdeh hr the x meldquot drep duwnbux seteet the Eastahg eeerdrhate In the drep duwnbux seieettheNerthth eeerdrhate HrttheOKhutteh rThe dataynu he drptayed as ahewtayerrs addedte yeurmap named Evanti39 add added tn the tep ufthe layers hst Yuu may ehek en the symhed te change its shape size and eeder y meldquot 5 Kriging Now it is time to generate artifact distribution maps We will be using Kriging Recall that this is weighted average method where the weights are estimated to that they minimize the sum of squared prediction errors The weights are constructed using information on the character of spatial autocorrelation in the known data points This information is summarized in the variogram So a rst step to kriging is to estimate the variogram for the data in question We will use ArcGIS s Geostatistical Wizard to do this you can also krige in Spatial Analyst and 3D Analyst The implementations look simpler and more user friendly because you don t have to look at variograms but harder to use intelligently for the same reason Make sure Geostatistical Analyst is active Tools gt Extensions gt Geostatistical Analyst and that its toolbar is visible View gt Toolbars Choose Geos tat i st ical Ni 2 ard from the Geostatistical Analyst menu Specify the Input Dataset and the Attribute variable you want to interpolate eg RedPipes Under Methods choose Kriging Click Next Choose Ordinary Kriging Prediction Map without transformations or trend removal Click Next Now we can check out the semivariogram or variogram for short and its cousin a graph of autocovariance Check out the semivariogram cloud plot Under Models stick with the default Spherical This is a particular kind of mathematical function that is being t to semivariogram cloud it is graphed in yellow on the semivariogram panel When there is positive spatial autocorrelation the yellow line should slope up Note the Maj or Range This is an estimate based on the Spherical Model of the distance over which where is positive spatial autocorrelation the point at which the yellow line is at Check out the other parameters Nugget and Partial Sill the partial sill is the difference between the nugget and the sill You can also choose Lag Size and Number of Lags Take a minute to eXperimentwith Lag Size and Number of Lags Click Next Now we look at the search neighborhood This offers information on what data points are going to be considered in doing the interpolating a value at the given spot Note the choice oftwo Preview Types Surface and Neighbors Take some time to play with the Shape Type and Neighbors to Include parameters can you see what is happening here The default value will work well Check out their effects on the Surface and Nei ghbors previews Click Next The next window gives you some indication of how good a job kriging is going to do It does this by dropping each known point from the data set then estimating its value by kriging from the remaining known data points This is called cross validation Click Finish You get a summary of the model Check out all you hard work Complete the process by clicking on OK in the last dialog Note that the resulting interpolated surface covers a bounding rectangle around the sample points Rearrange the layers so that you can see the quadrat centroids and features on top of the predicted u ace 6 Better Display There are several ways you can make the display more sensible You can change the extent of the rectangle containing the predicted surface In the Ordinary Kriging layer ie the one containing the predicted surface right click and select Properties select the Extent tab Check out the options in the Set the extent to drop down list Choose Limits of Excavation You can also change the color ramp and contour intervals of the display In the Ordinary Kriging layer right click and select Properties select the Symbology tab Right click Filled Contours The interpolated surface can be portrayed in a number of different ways This is set in the Symbology Property ofthe layer The default is Fi lled Cont our s but you can also choose Hill shade Contours or Grid right click on the Ordinary Kriging layer and select Properties select the Symbology tab uncheck Filled Contours and check Contours instead click OK to see the effect experiment with the other types of symbology for the predicted surface To limit the interpolated surface map to the area with the Limits of Excavation you need to change the Properties ofthe Layers Right click on Layers select Properties and click on the Data Frame tab In the Data Frame Properties dialog nd the Clip to Shape item and check the Enable box Choose the LimitsofExcavation layer as the shape to use to clip with Click OK 7 Saving your kriged surface to a raster file The predicted surface can be turned into a permanent feature class or shape le by means of the Data Export function This will allow you to then use the predicted surface in other analyses For example once you have several surfaces you will probably want to do things like compute the percentage of Red Clay Pipes If you have exported grid surfaces or rasters you can do these kinds of analyses using the ArcGIS Spatial Analyst Extension Rast er Cal cul ator rSelectLhekngmglayer g dmk ebansenaea gt Export ea Raster InLhe Export ea Raster dlalugbux nntetlneOnepne Raster eld Yaueanelnange thstu snrnetlnng rnare senSlble than the defanlL whlch wlll be sarnetlnnglllte gaigrld Mm myou Imowwhmdireamyuremw lewiubaavadin ryau used l Thls ylelas ane mtezpulated value every l full when the n and y cuurdmates are gvmm feet aws 52 a Ealumns ZUS a B ack lnlelvalallan Palms ln the E2 banana m yelleal jl Empm Raslel b Im4lsesalh585Pmlecl2EhHsAl E EeHElze l When Arcsz asks lf yuu want tn add the raster tn the new map ellelt Yes The newraster wlll appear as abaelt and while eananuaus tune rendmng UUUUUGLY We Wlll xltlater 8 Use the Raster Calculator to clean up interpolation errors Check nut the numene seale tn the ra er 77 ll pmba uly has negaave valuea wlneb ls aprablan valuestu I s Tu an ths weusetbe Raster Calculatur Map Algebra mm n rFuV w l lw dul Wquot l h w l Analyst Onteyuu see he Spatial Analys t menu choose Opti 0115 On he Genera e m wrkz39ng m39retlmy is he m39rerlmy hat cuntabnyuur es The Raster Calculatur alalag bux ls shuwn beluw wpp28 r wpmexxgrgt quotwpp23 r d ennenennnem ewe Ll TheLayers Wmduwhststherastersthatyuuhzvetreated Thebuxbeluthcuntmnsamap algebra funnula e nuts huWLhe rasLErs are used as arms m the equanun The funnulahere uses ununera er wplpesESr The rstta39munthengutwplpesESI gt u xsa lugxcal funnula Hells Raster Calculaturtu luuk at every eeu m the mput mater and chenkxt me WhPmM Lu m than u unchanged and nut I s m eeuS that are less than Dr equal m I nally ths resultxs assigned saved m amen calledwp1pesE 92 e spam AnalysL Wm add me 2 autumancally Warning The RasterCaIEulatuns VERYpamculzr abuuthuwyuu wnte nrmulas Make sure yuu have a space nn each sme ufany enemy 2 g wplpesESr wp1pesE9r gt u wplpesESr 9 Making the raster look good guud rSelectLherastennLheDlzypznelnghtchck EhuusePrupermes gt Symhulugy InLhe Symhulugy panel change he nsnley under Shaw 39nm Stretched m Classlfled rChangeLhenumberClasses tn1ULhede hdtxsiwhmhxstuufsw chekune Classlfybu un cheeknumnennnnns Which duyuuthmkwurksbeg7why7
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'