MAPPING SPATIAL DISTRIBUTION OF CHOSEN ENVIRONMENTAL CHARACTERISTICS FOR AGRICULTURAL USE IN LOWER SILESIA1

Transkrypt

1 Acta Sci. Pol., Geodesia et Descriptio Terrarum 2 (2) 203, ISSN (prit) ISSN (o-lie) MAPPING SPATIAL DISTRIBUTION OF CHOSEN ENVIRONMENTAL CHARACTERISTICS FOR AGRICULTURAL USE IN LOWER SILESIA Katarzya Kopańczyk, Halia Klimczak Wrocław Uiversity of Evirometal ad Life Scieces Abstract. Spatial statistics allows to assess geographic distributio of pheomea its cocetratio, magitude ad orietatio of dispersio as well regularity or treds i occurrece withi a space. The paper presets adaptatio of poit-based methods to measure spatial distributio of areal pheomea that cocer agriculture: area of agricultural lad, area of fertile agricultural lad ad soil ph. The source data i a form of chorochromatic maps (e.g. a vector soil map) are processed to x km grid data with use of the algorithm created i Model Builder. The research area Lower Silesia characterizes various evirometal coditios that results i chageability of agricultural lad productivity. Spatial statistics performed for a whole regio would brig oly global iformatio o spatial distributio. Hece the Authors propose to coduct aalysis withi subareas that depict local chageability of studied pheomea. As the research is coducted i agricultural cotext, the subareas of similar agricultural lad areas are created regardig the admiistrative uits. Spatial distributio is described by: mea cetre, stadard distace ad stadard deviatioal ellipse. All three measures are weighted by a variable (i.e. the itesity of the pheomeo) as spatial distributio is ot oly about locatio, but the value of the pheomeo i particular locatio is importat. Measures of spatial distributio draw o a map yields clear ad usually easy to iterpret iformatio o spatial character of a pheomeo. I some cases it may be useful to preset these qualitative characteristics complemeted with aother type of cartographic visualizatio (e.g. a choropleth map. This paper presets maps about the applicatio of spatial distributio measures ito assessmet of agricultural lad productivity i the research. Key words: spatial distributio, cetrographic method, mea cetre, stadard distace, stadard deviatioal ellipse Copyright by Wrocław Uiversity of Evirometal ad Life Scieces Address correspodece to Adres do korespodecji: Katarzya Kopańczyk, Wrocław Uiversity of Evirometal ad Life Scieces, katarzya.kopaczyk@igig.up.wroc.pl

2 30 K. Kopańczyk, H. Klimczak INTRODUCTION The visual aalysis of pheomea preseted o maps allow for geeral assessmet of geographic distributio. To discover patters i spatial relatioships ad local characteristics of pheomeo itesity oe requires quatitative measures. Implemetatio of statistical aalysis of spatial data i GIS software allow besides calculatig the measures to visualize the outcomes. Various spatial statistics techiques to assess geographic distributio of pheomea are available i the literature [Aseli 999, Cliff ad Ord 98, 992, Earickso ad Harli 994, Ebdo 985, Jażdżewska 2003, Maguszewski 999, Miller 2004, Urbański 2008]. However, the majority of them is used for distributio measuremets of poit data [Logley et al. 2006]. The paper presets adaptatio of poit-based methods to measure spatial distributio of areal pheomea coected with agriculture. The research area Lower Silesia regio (Fig. ) characterizes various evirometal coditios that results i chageability of agricultural lad productivity. It is located i south-wester Polad ad comprises of lowlads of high potetial agricultural use as well as moutaious areas represetig less-favoured areas for agricultural productio. The relief variability traslates also o soil, water ad climate coditios. Spatial statistics aalysis for a whole regio would brig oly global iformatio o geographic distributio. Hece it is proposed to coduct aalysis withi subareas that depict local chageability of studied pheomea. As the research is coducted i agricultural cotext, the subareas of similar agricultural lad areas are proposed (Fig. ). The boudaries are created regardig the admiistrative borders of the couties. Fig.. Subareas of similar agricultural lad area agaist the backgroud of agricultural lad Rys.. Podobszary o zbliżoej powierzchi użytków rolych a tle użytków rolych Acta Sci. Pol.

3 Mappig spatial distributio of chose... 3 SOURCE DATA AND ITS PROCESSING I this study chose pheomea that affects agricultural productivity are take uder cosideratio: area of agricultural lad, area of fertile agricultural lad ad soil ph. The agricultural lad are extracted from vector soil map of Lower Silesia i a scale of : (source: Regioal Cetre of Geodetic ad Cartographic Documetatio (WODGIK)). The map cotais also iformatio o lad potetial productivity discered as 3 types o arable lads ad 3 types o meadow ad grass-lad. Determiatio of the types is based o soil type, its physical ad chemical parameters, relief, climate ad water coditios [Witek 993]. The idex of quality ad agricultural productivity of lad describes each type ad rages from 8 to 94 poits withi arable lads ad from 20 to 80 poits withi meadows ad grasslads [Stuczyński et al. 2007]. The fertile agricultural lad are determied based o the idex values ad detailed descriptio of each type [Stuczyński et al. 2007]: over 64 poits for arable lads ad 80 poits for meadows ad grasslads. The distributio of fertile lad o agaist the agricultural lad is preseted i Figure 2. Fig. 2. Distributio of high fertile agricultural lad o the backgroud of agricultural lad Fig. 2. Rozmieszczeie gleb zakwalifikowaych jako dobre a tle użytków rolych Iformatio o soil ph is derived from the map presetig physical ad chemical parameters of agriculturally used soils i the scale of : [Stuczyński et al. 2007]. Figure 3 shows the distributio of soil ph withi the research area. ph of soil, which is optimal for crop productio ( ) is uder cosideratio i the further research. Geodesia et Descriptio Terrarum 2 (2) 203

4 32 K. Kopańczyk, H. Klimczak Fig. 3. Distributio of soil ph Rys. 3. Rozmieszczeie odczyu gleby Measurig spatial distributio requires trasformatio from qualitative approach (omial scale) to quatitative scale. The cotiuous or semi-cotiuous pheomea (e.g. agricultural lad; soil ph) are chaged ito discrete data usig grid of x km. The geometric referece uits are created accordig to divisio of Polad i TEMKART system [Podlacha 986]. The size of grid is adopted to the study area ad impacts o the accuracy of aalysis that has bee a issue i the separate research [Klimczak at el. 2006]. The costructed algorithm of data geoprocessig has bee created i ModelBuilder i ArcGIS (Fig. 4). It eables automatic coversio of qualitative data preseted o chorochromatic map (e.g. a soil map) ito a database composed of grid uits with qualitative attributes. The model has several parameters (letter p i a scheme) that make it useful for ay source data, ay study area ad ay referece uit. Fig. 4. Algorithm of data processig from qualitative to quatitative approach Fig. 4. Algorytm przetwarzaia daych wyrażoych w skali jakościowej a ilościową Acta Sci. Pol.

5 Mappig spatial distributio of chose The Lower Silesia covers referece uits of size x km (i.e. database features). The three characteristics calculated as the result of geoprocessig (see Fig. 4) are the percetage share of: agricultural lad areas, high fertile agricultural lad areas, optimal soil ph areas i the referece uit. The umber of features cosidered i the aalysis varies depedig o a pheomea: (agricultural lad), (high fertile agricultural lad areas), (optimal soil ph areas). Methodology Spatial distributio is ot oly about locatio, but the itesity of the pheomeo i particular locatio is importat. The spatial measure that regards the attributes values of the features is weighted mea cetre. The weighted mea cetre called also a geographic cetre is two-dimesioal average weighted by a variable ad it is calculated accordig to the followig formula [Maguszewski 999]: x = wi wi xi y = = wi y i () wi where x, y cetre (cetroid), w i value of a variable (attribute value) x i, y i coordiates of a feature, umber of features. The measure basically relates to the cocetratio of poits (x ad y coordiates). I the paper, the cetrographic method is adopted to polygo features with the assumptio that the cetroid s coordiates of referece uits are take ito accout. The iformatio o geographic cetre of the pheomeo is complemeted with measure of its dispersio from a mea cetre expressed by a stadard distace. It is a twodimesioal equivalet to stadard deviatio ad is calculated as follows [Jażdżewska 2003]: r wi( x i x) = + wi wi ( y i y) wi (2) where x, y cetre (cetroid), w i value of a variable (a pheomeo) x i, y i, coordiates of a feature, umber of features. Determiatio of weighted mea cetres ad stadard distaces withi subareas ad their visualizatio o a map allow for aalysig local treds i spatial distributio. Moreover, the utility of the mea cetre is for comparig spatial distributio of differet pheomea ad may brig iformatio o correlatio betwee them. Geodesia et Descriptio Terrarum 2 (2) 203

6 34 K. Kopańczyk, H. Klimczak The aforemetioed spatial measures yields iformatio o magitude of dispersio, but ot its directios. I order to assess the directioal treds the stadard deviatioal ellipse is used. The agle of rotatio of a ellipse is give as [Ebdo 985]: ( ) 4( ) ' ' 2 2( xy i i) '2 '2 '2 '2 2 ' ' 2 i i + i i + i i x y x y x y tgα = (3) where: ' ' x = x x, y = y y The axes of the ellipse are defied as the stadard deviatio of the x coordiates ad y coordiates from the mea cetre: ( x ) ( x y ) ( y ) '2 cos 2 α 2 ' ' si αcosα+ '2 si 2 α σ x = (4) σ = y ( x ) ( x y ) ( y ) si α 2 si αcosα+ cos α '2 2 ' ' '2 2 (5) It should be oticed that the stadard deviatioal ellipse may be calculated usig either the locatios of the features or usig the locatios iflueced by a attribute value associated with the features (w i ). I the research, the latter oe weighted stadard deviatioal ellipse is used ad allows to see whether the distributio of the pheomea is elogated ad hece has a particular orietatio. RESULTS Measures of spatial distributio draw o a map yields clear ad usually easy to iterpret iformatio o spatial character of a pheomeo. I some cases it may be useful to preset these qualitative characteristics complemeted with aother type of cartographic visualizatio. Figure 5 shows the localizatio of mea cetres ad stadard distaces calculated for high fertile agricultural lads o the backgroud of the choropleth map presetig percetage share of these lads i a referece uit. The essetial cocetratio of high fertile agricultural lads may be oticed i eight of fiftee subareas: 6, 7, 8, 9, 0, 2, 3, 4. Whereas the biggest dispersio characterizes subareas umber: 2, 3 ad 5 located i the orther part of Lower Silesia. What should be stressed out that mappig spatial statistical measures delivers additioal iformatio which may be differet from visual assessmet of studied pheomeo based o a choropleth map. Oe may otice similar itesity of the high fertile agricultural lads i 2 ad 8 subareas, however oly the locatio of the mea cetre shows the place where the pheomeo is cocetrated ad stadard distace poits that the fertile lads are more codesed i the 8 th subarea tha i the 2 d. Acta Sci. Pol.

7 Mappig spatial distributio of chose Fig. 5. Spatial distributio measures for high fertile agricultural lad Fig. 5. Miary rozkładu przestrzeego dla gleb zakwalifikowaych jako dobre The stadard distace shows the degree of dispersio of the pheomeo. I order to see the directios of dispersio which are also valuable characteristics of spatial distributio, the stadard deviatioal ellipse is cosidered. The figure 6 presets the ellipses for agricultural lads calculated i subareas. It should be stressed out that due to that fact that parameters of the stadard deviatioal ellipses are related to the size ad shape of the subareas, the better solutio is to aalyse the data withi subareas of the similar shape ad size. The example of such subareas is proposed i a form of squares of 27 x 27 km created based o the x km grid referece uits (Fig. 8). The assumptio is to cover the whole Lower Silesia ot overestimatig the area. However, the choice of size, shape ad locatio of these subareas should be a issue of a further research. The Authors otice that aalysis i subareas regardless its size ad shape is appropriate ad useful for comparig a few pheomea. That is importat especially i applicatio studies such as agricultural use of lad whe various factors are take ito cosideratio. Presetig a few pheomea o oe map delivers iformatio o the possible correlatio betwee them. I order to ivestigate the correlatio i spatial distributio of agricultural lads ad the soil coditios, the cetroids ad stadard deviatioal ellipses are determied for: agricultural lad, fertile agricultural lad ad optimal soil ph (Fig. 7). Geodesia et Descriptio Terrarum 2 (2) 203

8 36 K. Kopańczyk, H. Klimczak Fig. 6. Spatial distributio measures for agricultural lad Fig. 6. Miary rozkładu przestrzeego dla użytków rolych Fig. 7. Compariso of spatial distributio measures for the three pheomea i subareas of similar agricultural lad area Rys. 7. Porówaie miar rozkładu przestrzeego trzech zjawisk w podobszarach o zbliżoej powierzchi użytków rolych Acta Sci. Pol.

9 Mappig spatial distributio of chose The visual aalysis of the outcomes (Fig. 7) leads to coclusio that i some subareas (e.g. 7, 0, 2) "geographic cetre" (cetroid) of agricultural lad ad favourable coditios for agriculture are correspodig to each other, as well the dispersio ad its directios are overlappig. There are also regios where the variability of pheomea withi a space is bigger. For istace, 9 th subarea the agricultural lad occur withi the whole area, while the fertile agricultural lad ad soil of optimal ph are cocetrated i its orther part. Moreover, the directios of dispersio are differet: orth-east for fertile agricultural lad ad south-west for optimal soil ph. Similar situatio ca be observed i the 8 th subarea where the cocetratio of favourable coditios for agriculture are located i the orther part. The 5 th subarea is characterized by high fertility of all agricultural lad (the ellipses of agricultural lad ad high fertile agricultural lad are early overlappig), but the soil coditios are located i the orth-west. Fig. 8. Compariso of spatial distributio measures for the three pheomea i subareas of equal size ad shape Rys. 8. Porówaie miar rozkładu przestrzeego trzech zjawisk w podobszarach o takim samym kształcie i rówej powierzchi The aalysis of the same coditios i equal subareas (Fig. 8) cofirmed the observatios that the most favourable coditios of agricultural lad are located i the cetral part of Lower Silesia (the all three cetroids ad ellipses are overlappig). There are differeces i spatial distributio i the outer subareas, maily i directio of dispersio of high fertile agricultural lad. Geodesia et Descriptio Terrarum 2 (2) 203

10 38 K. Kopańczyk, H. Klimczak CONCLUSION I aalysig the spatial distributio its cocetratio or dispersio ad their directios it is essetial to map the outcomes. The visualizatio of locatio of the "geographic cetre" ad orietatio of the distributio brigs additioal ad useful iformatio o the studied pheomea. The paper presets the applicatio of spatial distributio measures (weighted mea cetre, stadard distace, deviatioal ellipse) ito assessmet of agricultural lad productivity i Lower Silesia. I order to aalyse the local chageability of the pheomea, the subareas of similar agricultural lad area are proposed. The Authors otice that these subareas are more relevat to compariso of differet pheomea withi the same subarea, tha to aalyse a pheomeo i a global scale (withi whole regio). That is due to the fact that the stadard deviatioal ellipse parameters relates to the shape ad size of the subarea. The example of equal subareas is preseted, however the choice of their size, shape ad locatio should be a issue of a further research. Mappig spatial distributio of the three factors (agricultural lad, high fertile agricultural lad ad optimal soil ph) brigs the coclusio that the cetral part of Lower Silesia is the most favourable regio for agricultural use, especially i subareas where the stadard deviatioal ellipses ad cetroids are early overlappig (subareas 7 th, 0 th, 2 th ) which meas that the best soil coditios ad fertile lad are withi all agricultural lads. These areas costitute early 20% of agricultural lad i Lower Silesia ad embraces most of the area withi Silesia Lowlads. The research revealed also the regios where the distributio of the favourable coditios are located i a specific places of agricultural lad (subarea 8 th, 9 th, 5 th ). That relates to the south-wester part of Lower Silesia. WIZUALIZACJA ROZKŁADU PRZESTRZENNEGO WYBRANYCH ELEMENTÓW ŚRODOWISKA PRZYRODNICZEGO ZWIĄZANYCH Z GOSPODARKĄ ROLNĄ W WOJEWÓDZTWIE DOLNOŚLĄSKIM Streszczeie: Statystyki przestrzee pozwalają opisać i oceić zjawisko pod kątem jego przestrzeych charakterystyk takich jak: kocetracja, wielkość i ukierukowaie rozproszeia, występowaie regularości lub tredów w przestrzei. W artykule zaprezetowao adaptację metod stosowaych dla zjawisk puktowych do ocey rozkładu przestrzeego zjawisk powierzchiowych związaych z gospodarką rolą: powierzchia użytków rolych, powierzchia gleb zakwalifikowaych jako dobre, powierzchia gleb o daym odczyie. Mapy zasięgów tych zjawisk (p. mapa glebowo-rolicza w postaci wektorowej) jako jakościowe dae wejściowe zostały przetworzoe a dae ilościowe odiesioe do siatki o wymiarach x km za pomocą algorytmu stworzoego w środowisku Model Builder. Obszarem badań jest województwo dolośląskie charakteryzujące się różorodością waruków przyrodiczych, co wpływa a zmieość przydatości roliczej badaego tereu. Statystyki przestrzee wyzaczoe dla całego obszaru dostarczają tylko ogólej iformacji o rozkładzie przestrzeym, stąd też w pracy przeprowadzoo aalizy w podobszarach, co pozwoliło a zbadaie lokalej zmieości wybraych waruków przyrodiczych. Z uwagi a roliczy aspekt badań zapropoowao podobszary o rówej powierzchi użytków rolych, uwzględiając graice admiistracyje. Rozkład przestrzey opisują takie miary jak: środek ciężkości, odległość stadardowa, elipsa odchyleń stadardowych. Uwzględ- Acta Sci. Pol.

11 Mappig spatial distributio of chose iają oe ie tylko lokalizację obiektu, ale rówież wartość zjawiska. Wizualizacja miar rozkładu przestrzeego a mapie dostarcza jasej i zwykle łatwej w iterpretacji iformacji o strukturze przestrzeej badaego zjawiska. Prezetacja tych ilościowych charakterystyk a tle zjawiska przedstawioego ią metodą kartograficzą (p. metodą kartogramu) może wosić dodatkowe iformacje, w tym przypadku dotyczące przydatości waruków przyrodiczych dla gospodarki rolej. Słowa kluczowe: rozkład przestrzey, metoda cetrograficza, środek ciężkości, odległość stadardowa, elipsa odchyleń stadardowych REFERENCES Aseli L., 999. Iteractive techiques ad exploratory spatial data aalysis [i:] Geographic Iformatio Systems: Priciples, techiques, maagemet ad applicatios., ed. Logley P.A., Goodchild M.F., Maguire D.J., Rhid D.W., New York: Joh Wiley ad Sos. Cliff A.D., Ord J.K., 98. Spatial Process: Models ad Applicatios. Pio, Lodo. Earickso R., Harli J., 994. Geographic measuremet ad quatitative aalysis. Macmilla College Paublishig Compay, New York. Ebdo D., 985. Statistics i Geography. Basil Blackwell, Oxford. Getis A., Ord J.K., 992. The aalysis of spatial associatio by the use of distace statistics. Geographical Aalysis, vol. 24, Jażdżewska I.,2003. Statystyka dla geografów. Wydawictwo Uiwersytetu Łódzkiego, Łódź. Klimczak H., Galat K., Alkśi M., Modellig of spatial structure of chose forms of lad cover usig geometric referece uits. Reports o Geodesy. Logley P.A., Goodchild M.F., Maguire D.J., Rhid D.W., GIS. Teoria i praktyka. Wydawictwo Naukowe PWN, Warszawa. Maguszewski A., 999. GIS w geografii fizyczej. Wydawictwo Naukowe PWN, Warszawa Miller H.J., Tobler s First Law ad Spatial Aalysis. Aals of the Associatio of America Geographers, vol. 94, o. 2, Podlacha K., 986. Kartograficzy system TEMKART dla komputerowego sporządzaia map tematyczych. Prace IGiK, t. XXXII, z. 2, Warszawa. Stuczyński T. (red.) i i., 2007a. Sta i zmiay właściwości gleb użytkowaych roliczo w województwie dolośląskim w latach Urząd Marszałkowski Województwa Dolośląskiego, Istytut Upraw Nawożeia i Glebozawstwa, Państwowy Istytut Badawczy, Puławy Wrocław. Urbański J., GIS w badaiach przyrodiczych. Wydawictwo Uiwersytetu Gdańskiego, Gdańsk. Witek T. i ii, 993. Waloryzacja roliczej przestrzei produkcyjej Polski według gmi. IUNG, Puławy. Seria (a) 56. Zaakceptowao do druku Accepted for prit: For citatio Do cytowaia: Kopańczyk K., Klimczak H., 203. Mappig spatial distributio of chose evirometal characteristics for agricultural use i Lower Silesia. Acta Sci. Pol. Geod. Descr. Terr., 2 (2), Geodesia et Descriptio Terrarum 2 (2) 203

12