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So, the topics that we are going to cover today; the concepts that we are going to cover todayis what is landscape composition and how I mean, it has an impact on ecological assessment.We are going to talk about landscape configuration, we shall see what are the properties oflandscape metrics, and then some application areas of landscape metrics.
(Refer Slide Time: 01:11)
So, we know about land covers; so, just let us do a recap. So, a land cover is the physicalcover of earth; I mean, depending on what type of coverage you have it maybe soil, it maybevegetation, it maybe forest, it may be urban areas, buildup areas. So, the physical cover on theearth; I mean, gives the land cover where in land use is the use of a particular piece of land byhumans.
So, it these two metrics that is land use and land cover it gives us a baseline for a lot ofstudies, such as societal studies or studies related to ecological parameters or ecological
assessment. So, these studies could be in for environmental modeling, it could be related toweather and climate studies. We can also do hydrological or landscape planning studies usingthe land cover and land use metrics . There are different standards of land use and land coverdeveloped by different agencies across world and varying in skills.
So, some of these important ones are the BHUVAN land cover assessment of India which isdeveloped by ISRO. We have NCLD that is the National Land Cover Database for UnitedStates. We have LCCS that is the United Nations Land cover maps of Food and AgriculturalOrganization. We have CORINE which covers European Union it is the Coordination ofInformation on Environment.
So, we see there are different; I mean, land cover and land use nomenclatures systemsdeveloped in different countries by different agencies. Now, the disadvantage of preparingland use maps or it could be the time consuming process, I mean which is if we are doing onscreen digitization of high resolution images. So, there what we do is we bank up on machinelearning algorithms or say different land classification algorithms by which we can create; Imean, or digitize or I mean automate the process of land use creation.
So, in remote sensing once we get the satellite images, there are different processes methodsby which we can automate the process of land use maps and then we can go for an assessmentof accuracy. So, the I mean, this land use and land cover maps they give us the characteristicsof the earth surface and this is important for the different types of applications inenvironmental modeling, weather systems modeling or interaction of weather climate systemswe say we urban development. So, we can do a micro scale or a major scale model, we canalso work on hydrological and landscape planning I mean interaction models.
So, these are some of the important things which can be studied using the land use land cover.Now, land use and land cover become the basis to analyze the patterns in a given landscape.So, by landscape we are; meaning, that it is the area of study that I mean you are enforcingdifferent types of algorithms or measures or indices. So; I mean, these become very important
base maps; I mean, the land use and land cover they are useful for analyzing the patterns in agiven landscape.
(Refer Slide Time: 05:26)
So, now talking about landscape metric; I mean, your Gordon, Forman I mean, they hadtalked about landscape and they have defined it as a heterogeneous land area. I mean, ofdissimilar elements, dissimilar; I mean types of landforms land patterns land use which iscomposed of a cluster of interacting eco-systems. So; I mean, it may have sub ecosystemswhich would be interacting with each other and that is this ecosystems would be repeated inthe landscape.
So, Gordon and Forman they formulize this landscape metrics the study of a landscape usingdifferent types of metrics to characterize the geometric and the spatial properties of differentareas; I mean, of say map patterns or say land use patterns in I mean different areas. So, we
can use this different metrics for assessing the quantitative or we can do and objective analysisof the different landscape types. Now, we had said in a landscape type it is composed ofinteracting ecosystems.
So, we can do an objective as well as quantitative analysis of this interactions happeningwithin the ecosystem using landscape metrics. So, I mean it can also be used these metrics toassess the policies; I mean, if we take a policy decision related to environmental management.So, we can do an assessment of future scenarios. So; I mean, the environmental goals I meanlike we have the sustainable development goal and other I mean, different agendas so, by theinternational charter of agreements.
So, we can monitor what is the progress using this type of metrics. So, it is used for; it is avery useful tool when we want to measure the arrangement of the components. Thiscomponents in a landscape in a temporal fashion or even in a spatial manner. So, in space andtime we can use this tools very effectively to manage the landscape components.
Now, we can also characterize the different spatial patterns, if the area of an urban area or aregional region has us characteristics spatial pattern. It can be; I mean, assessed using thelandscape metrics or even if these are varying across time and space as we have talked about.These spatial patterns can be assessed of the different landscape components.
Now, that there are different processes; I mean, in urban area we know that there are differentway processes which goes on in transforming the land from one land cover type to; I mean,different land cover type one land use type to different land use type. For example, there areeconomic and ecological I mean, factors which are responsible for these spatial processes, itaffects the landscape in various ways.
So; I mean, this would cause an; I mean, the outcome of these processes would be its impacton the spatial pattern and the how these different; I mean, ecosystems interact and thereby theecological processes. So, this landscape pattern analysis it is the study of component of thespatial patterns.
(Refer Slide Time: 09:48)
So, there are different types of categories which can be used to assess the landscapecomposition variation. So, we look to the spatial attributes of the landscape configuration. So,we also look for the, I mean spatial information to calculate these metrics.
So, for the landscape composition; I mean, it can be easily quantified using the landscapemetrics. So, there is we can also assess if there is abundance of a particular patch type within agiven landscape and without considering the spatial characteristics of how it is placed or Imean, how the I mean, what is the location of these kind of patches in the landscape mosaic.
So; I mean, this landscape composition are the principle measures I mean, of this particularlandscape composition are the proportion of a proportional abundance of each class where inone class could be dominating over other classes. So, we can find out the abundance of thedifferent type of classes that we have in a given landscape. So, it is a very simple and very
useful information and we can find out the proportional representation of each class in relationto the entire map.
Now, we can also find out the richness; in landscape composition we can find out the richnessthat is the variety in types of the different this landscape patches. So, we can also find out theevenness, if the distribution of this different landscape patches. In this particular compositionare evenly distributed which typically emphasizes, if a particular class is dominant or it is Imean, complement, complementary or there is equability in distribution of the different classes.
So, we can have these different types of measures where in we can measure the abundance, wecan measure the richness of different patch types and we can measure the evenness. Now, wecan also measure the diversity. So, this is the measure of richness and evenness and it can becalculated or computed by different forms.
(Refer Slide Time: 12:42)
So, the landscape configuration is really difficult to quantify. Now, we have the different typesof spatial arrangement, the character spatial character, the orientation of the patchespositioning within a landscape for a particular class. Now, these landscape configuration Imean, this principle measures are patch size distribution and its density. So, it gives us thespatial character of the patches.
Now, the second type of landscape configuration measure is the shape complexity that howcomplex is the geometry of the patches. So, you can find out whether there are simple; theseshapes are simple in nature or they are very convoluted or irregular, they are dispersed orwhether they are compact. So, you can identify the diversity in terms of the geometry of thepatches using such measures of landscape configuration.
We can find out I mean, the measure of landscape composition which is the core area identifythe core area which is which signifies that it is the interior of a patch that is we can use a Imean, if we have a edge buffer we can eliminate that buffer region and then we can go into thecore area. So, we can find out different metrics for the core area. So; I mean, in the landscapeconfiguration first we had talked about the distribution and density of the different types ofpatches, the complexity in terms of the shape and then the core area, then we can also measurethe isolation or a measure of the proximity.
So, the how proximal are the patches whether they are isolated or whether they arecongregated. So, the distance between the patches between similar and dissimilar classes canbe found out; I mean similar, classes or dissimilar classes means that is they are ecologicallycompatible or ecologically incompatible classes.
Now, we can also measure the contrast. So; I mean, the difference between the different typesof patches can also be measured; I mean, we can do a relative assessment of these measureusing contrast metrics. We can also find out how these patches are dispersed using dispersionmetrics. So, whether they are contagiously distributed that is they are clumped or they areclose together aggregated or they are regularly distributed with respect to one another.
Now, the next metric is the contagion or interspersion metric wherein there is a tendency ofthe patch type to be spatially aggregated that is to occur in large or aggregated contagiousdistribution. So, we can use the contagion or the interspersion metric to find out how theythese patch types are spatially aggregated or distributed.
We can also find out the subdivision of the patches that is the degree to which the patch typeis divided or subdivided into separate patches or fragments. So; I mean, this could be in termsof shape its location relative location or the spatial arrangement; so, we can also look for thesubdivision. So, for landscape configuration, we have the patch size distribution that is thedensity, we are talking about the complexity of the patches, we are talking about the core areametrics to identify the core area, we can identify whether the patches are isolated or relatively;I mean, distant from each other or close together aggregated.
So, isolation or proximity could be studied between this patches. Now we can also look forcontrast, the difference among the patch types; we can look for dispersion that is the regularlyor contagiously distributed patches whether they are clumped or disaggregated we can lookfor contagion. So, I mean, it is basically a metric for identifying whether the patches arespecially aggregated together and interspersion; how they are distributed amongst in thatparticular landscape that are different patches how they are distributed and then we can findout the subdivision.
So, using this type of metrics, we can assess the different interactions between the; I mean, subecological ecosystems existing within a landscape. Now, there are also connectivity basedmetrics that is to find out or assess whether there are functional connections or they thepatches are connected in some way functionally.
(Refer Slide Time: 18:28)
So, we can have some kind of connectivity measures to assess the functional measures. Whenwe are assessing this metrics or calculating this metric on a given landscape on the differentpatches of say land covers or land use, it is important that we use more than one metric.Because, of single metric may not be able to pick out all the different variabilities within aparticular land landscape.
So, we should use the different metrics from different metric groups we have already talkedabout these different groups. So, this metrics can be defined at the level of heterogeneity andaspect of landscape pattern. Now, if we talk about the level of heterogeneity, we can see thelevel of heterogeneity at the patch level where you can have patch level metrics whichrepresent discrete areas having similar characteristics; similar exhibiting similar characteristics.
We can have class level metrics. So, first we are assessing each and every patch and findingout the patch level metric, then we can have different classes aggregate this patches bydifferent classes and see how these classes are distributed or how these classes interact. So, wecan have class level metrics; so, I mean we can have class level metrics for specific classes insay land cover and land use and then we can have an overall landscape level metric, whichincludes all the different patches and the I mean, the class types given in an area.
So, in this particular figure, we can see that at the patch level we have some metrics. So, wehave some metrics at your class level; this A1, A2, B1, A3 and B2 these are the class levelmetrics and then we have the landscape level metrics at different levels. So, we can assess thedifferent measures.
(Refer Slide Time: 21:21)
Now, we can also assess the aspect of different land use patterns landscape patterns using areaand edge metrics. So, we have; we can deal or assess the sizes of the different patches and bythe amount of the edges that is created by this different patches. So, you can see that in thisparticular figure we have two images where in you can see there are final grains in the firstimage; top image and in the bottom one you can see the grains are coarse. So, we can identifythe edge as well as how the area of the patches are distributed in a given landscape.
Now, after the area and edge metrics we can look for shape metrics which I mean, gives anidea regarding the shape complexity, whether are shape is simple or it is cirated and verycomplex in nature, whether the patches are compact and we can find out how is the landscapeconfiguration.
So, you can see in the first one that same image, we have complex geometry in which I mean,the geometries are not really regular; I mean, the surfaces as created and the edges are verycomplex. So, there are; there you have a complex geometry and in the bottom one you can seethat you have patches which have simple geometry.
So, we can use shape metrics to identify whether the shapes are complex or whether theshapes are simple, then we had talked about the core metrics core area metrics. So, I mean,this describes the patch interior area after you are accounting for the edge depth of edgeeffects like we said we can do a buffering and remove the edge areas. So, we can remove theaccount for the depth of edge effects and then we can assess the core area.
So, in this case you have the first image you have less core area, you can see in the edges, youhave more I mean, different patches; more number of patches in the edges than the core area.And, in the second image you can see that you have I mean, the patches are congregated orthey are clumped together in the core area.
So, we can find out the aspect of landscape pattern using these three groups of metrics; one isthe area metric or the edge metric where we look for the size of the I mean, patches and theedge complexities. Second is the shape based metrics when we see the geometry complexity orcompactness of the patches and third is your core area metrics. So, we can find out whether Imean, how is the core area once you remove the depth of edge effects.
(Refer Slide Time: 24:33)
So, the aspect of landscape pattern can be studied also using contrast metrics. So, we hadtalked about this; I mean, we can identify describe the magnitude in terms of contrast. So; Imean, we can find out the contrast in the patch edges. So, in this two particular images youcan see the first one, in this particular image you have less contrast within the image where inalong the edges in the second image you have more contrast, you have different types of plantspecies. So, there is more contrast.
Now, we can also look for aggregation metrics which has I mean, gives the patch types; Imean, which is spatially aggregated; I mean, in this aggregation metric we can see whether thepatches are contiguous or they are aggregated in terms of its distribution. So, we can studythat using the aggregation metric.
So, it is often also referred to as the texture; the landscape texture. So, in this particular imagewe can see that in the very first image we see a lower level of aggregation and as we move tothe right. I mean, we can see a high level of aggregation in which these points are clumpedtogether and the I mean, patches are aggregated, you can see it is aggregated in some fewpatches 3 or 4 patches out here in this particular image where in it is more or less dispersed.So; I mean, these are basically a comparison of high and low aggregation measures.
(Refer Slide Time: 26:33)
Now, if we see the aspect of landscape pattern, we can refer to the subdivision metric whichwe had already talked about. So, it is allied to the aggregation metric that describe the degreeof subdivision of a particular class or the given landscape. So, you can see those sameexamples; I mean, where in you have high sub division and the bottom one where in you cansee low subdivision.
Now, we can also identify the aspect of the pattern of landscape using isolation metric whichgives; I mean, how the I mean aggregated your landscape patches are I mean, it gives us Imean an idea regarding the subdivision of the patches. So, that would describe the degree ofisolation of the different patches.
So, in the first image top image, you can see there is a low isolation; I mean, you have if wetake a search window then you can see that I mean, in close proximity of this central patch,you have similar patches; similar I mean patch. So, the isolation is in that case low, but in thenext image this isolation is very high. So, in the ecology or in terms of you are when we areanalyzing the land use pattern or the land cover pattern in an urban area. We can use this typeof subdivision metrics to assess the aspect of the different types of landscape pattern usingyour subdivision metric as well as isolation metric.
Now, we can also find out the diversity of the different type of patches that gives us thecomposition of the landscape. Now, if we go to this particular image we can see that in thiscase there are only few types of patches. So, there is in this case the diversity is very low, butin this image which is the bottom image, in this case you can see there are varieties of differenttypes of patches; so, the diversity is high. So, we can do this kind of analysis in using yourraster data, because your data size would be smaller and there are also tools which we woulddiscuss about.
(Refer Slide Time: 29:11)
So, I mean these kind of tools are available as plug ins in qgis, you will also have I mean, yourstandalone softwares like I mean Fragstats or Apache or there are different other software aswell. So, let us see some examples where this class metrics have been used; I mean, it can beused in patch, class or the landscape level and these are used I mean, these are derived fromthe patch level attributes for the each patches.
We would also have the attribute of these patches like which class does this attribute. Thispatch belongs to and whether these are integrated over the; I mean, in the landscape for aparticular classes; for a particular class of patches. We can also I mean do a class level metricanalysis for effective I mean, ecological identifying the effective ecological processes.
So, in this particular table we can see the different type of metric and how it is being used. So,you can see the, this these are the abbreviations of the metrics that you will come across in
different softwares, the percentage of the landscape. So, it gives us the particular percentageof or specific patch type in the given landscape then you can count the number of patches. So,number of patches or by class type you can find out using the number of the patch.
Now, the patch density would give you the patches of different classes per unit area. Now, wecan also find out the large patch index; largest patch index. So, I mean the area of the patchlargest patch divided by the landscape area. So, it is like a fractional measure, we can find outthe total edge parameter. So, this is the sum of lengths of the edge segments, the total edgethat you have for a different patches. So, we can find out the total edge, we can also find outthe edge density. So, it would give us the length of the edge segments divided by the total areaof the landscape.
Now, the next metric that we are talking about is the shape index; I mean, we had already seenhow the shape index is useful and how it is reflected in the image. This is the measure whichgives us an idea regarding its compactness and I mean, whether it is adjusted by the size of thepatches as well.
Now, we also have your area I mean, shape index which ways the patches according to size.So, you can use this two metrics alternately; I mean, either the Landscape Shape Index, LSI,or the area weighted mean shape index. In the your area weighted shape index what it does isit; I mean, finds out the I mean, shape I mean, size of the patch total length of the edge with.
And, it is; I mean, normalized with the landscape with the standard shape of a square or circlehaving an equivalent area of size of a given particular patch without any internal edges. So, wecan do assessment regarding how complex the shape is when we try to compare it with thestandard geometric shape. We can also I mean assess the total core area like we had said so, itcomes us as meter square. So, some of these metrics have meter I mean, units and some ofthese metrics they do not have units. So, we can also find out the nearest distance using theEuclidean. Nearest neighbor distance area weighted mean ah; measure.
So, it gives you the shortest straight line distance between focal point and the nearest neighborof a similar class. Now, we also have the next one which is the splitting index which gives you
the number of patches obtained by subdividing the landscape into equally sized patches basedon the effective mesh size; I mean, you would have to define a mesh size while you are doingthis particular I mean measure. So, you can give that effective mesh size and you can find outthe number of patches obtained by subdividing the landscape into equal size of patches whenyou are sieving it through a mesh.
Now, the last one that is the aggregation index would give you the ratio of number ofadjacencies to the maximum possible number of like adjacencies given in the proportion oflandscape, compromised of comprised of each patch type and it is given as percentage. So,these are some of the metrics which I mean, cuts across different types of categories.
(Refer Slide Time: 35:01)
So; I mean, we can use or apply this landscape metrics to understand change in the landscapeor I mean, with respect to the ecological aspects. I mean, how visually it is changing or the
cultural aspects of a landscape can be assessed. So, we can in this particular heads, we can doapplication related to biodiversity characterization and habitat analysis. We can do anassessment of the water quality and how it is impacted by the different types of land use thatyou have in an ecological set up in a landscape.
We can do an evaluation of the landscape pattern and the changes in that we can also assessthe urban pattern and the road network I mean the different types of variations. So, you cansee that high rise apartments would have a different type of a pattern than low rise apartmentslums. So, I mean, by these patterns probably you might be able to relate the different types ofareas and I mean, the uses I mean in urban area.
So, we can also assess the density of the road I mean, we can see how what are the number ofedges and whether the places are well connected accessibilities high. So, we can assess theroad network as well using the landscape metrics. So, specially like your edge metrics andother metrics can be used.
So, we can also; I mean, do I mean, applications related to aesthetics of the landscape, we cando proper management monitoring, planning in a given area. So; I mean, the contributions ofthe landscape ecology if you come across the literature I mean, it has been used effectivelyvery effectively to establish the relationship between landscape structure and the landscapefunction.
So, these landscape metrics are very effective to give you an estimate of the effects of planningactivities. So, you can do policy assessment that I mean, what is the impact of policies on agiven structure of land use. So, you can and on the ecological systems. So, that can beassessed; I mean, this landscape metrics I mean if we use it we can also quantify the structuralpatterns the characteristics which are necessary for a sustainable planning. So; I mean, we canalso understand the different underline ecological processes in a I mean, landscape using thiskind of landscape metrics.
We can also identify the changes that happen in the landscape in a temporal fashion; I mean,how the changes are happening over time can be assessed.
(Refer Slide Time: 38:16)
So, I mean, your Gordon and Forman they came up with the these different metrics;quantifying metrics. So, they came up with the computer program wherein they have abouquet of these different types of metric and this software is known as FRAGSTATS. Thereis also a software which is known as patch analyst there is a software which is known as apaca plus you would have plugins in QGIS where in you can calculate the different fragmentation,porosity patchiness, a lacunarity, contagion metrics and all the different type of metrics that wehave talked today.
So, we can; I mean, use this FRAGSTATS for assessing the spatial patterns and thisFRAGSTATS quantifies the spatial heterogeneity of the landscape, we can find out the
gradient in the landscape or we can find out how the different patterns interact in landscapemosaic. And, this is useful for; I mean, this software FRAGSTATS is helpful for generatingyour landscape metrics in a given area ah. It is flexible and I mean, in the define definition andit can also scale the different I mean, the different patches in the or different zones in yourlandscape.
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