Lecture 5 Raster Data Analysis. 2015-10-19 2 Introduction Analysis with raster data is simple and efficient for it’s feature based on position Analysis

Lecture 5 Raster Data AnalysisLecture 5 Raster Data Analysis

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Introduction

Analysis with raster data is simple Analysis with raster data is simple and efficient for it’s feature based and efficient for it’s feature based on positionon position

Analysis with raster data can be Analysis with raster data can be in a single, group, cellin a single, group, cell

The algorithm in raster data The algorithm in raster data analysis is different from that in analysis is different from that in vector datavector data

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Environment

Range Range specific grid give specific grid give region by max and min coordinateregion by max and min coordinate cell combined cell combined

merge merge intersectionintersection

mask gridmask grid Input gridInput grid

More than or equal to the input grid sizeMore than or equal to the input grid size

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Local function

Single cellSingle cell Not related to neighbor cellNot related to neighbor cell No effected by neighbor cellNo effected by neighbor cell New gridNew grid

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Mask grid

A region that exclude no data cell A region that exclude no data cell Data query and reclassificationData query and reclassification No data is not zero volume in cell, No data is not zero volume in cell,

zero is efficient data, the region zero is efficient data, the region which is no data is lack of datawhich is no data is lack of data

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Local function (Cont.)

Arithmetic operationTrigonometric function

logarithmpower

U= f (A, B,…)

A

A

B

C

U

U

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Local function (Cont.)

Numerical dataNumerical data max, minmax, min mean, summean, sum standards derritations valuefieldstandards derritations valuefield

measuremeasure majoritymajority minorityminority variety variety

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Local function (Cont.): Combination

3 2 1

2 1 2

1 2 3

3 2 4

3 2 4

2 4 1

1 3 6

2 4 5

4 5 7

1: 0-20%

2: 20%-40%

3: >40%

North: 1

East : 2

South : 3

West : 4

Combine code

Slope and aspect

1 3 ， 3

2 2 ， 3

3 2 ， 2

4 1 ， 2

5 2 ， 4

6 1 ， 4

7 3 ， 1

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Local function in ArcView

Cell statistics

Map calculator

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Application of local function in raster data Universal soil loss equation (USLE)Universal soil loss equation (USLE)

A A = = R K L S C PR K L S C P

AA ：： average loss of soilaverage loss of soil 平均土壤流失量；平均土壤流失量；RR ：： rainfall intensityrainfall intensity

KK：土壤可蚀性：土壤可蚀性LL ：： lengthlength

SS ：： slopeslope

CC ：： cultivation factorcultivation factor

PP ：： preserve measure in water and soilpreserve measure in water and soil

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Neighborhood function

Method involving a square window Method involving a square window over the surface and computing a new over the surface and computing a new value of the central cell of the windowvalue of the central cell of the window

Elements of neighborhood functionsElements of neighborhood functions central pointcentral point size and shape of neighborhoodsize and shape of neighborhood function function

Only in single layerOnly in single layer Moving windows scan all cellsMoving windows scan all cells

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Neighborhood function: size and shape of neighbor

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Functions of neighbor operation

mi

mi

nj

njijijij cfC )(

statisticsstatistics max, minmax, min

mean, summean, sum standards derritations standards derritations

valuefieldvaluefieldmeasuremeasure majoritymajority minorityminority varietyvariety

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Application of neighbor operation: data smooth

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Application of neighbor operation: variety

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Loop pass filter

Application of neighbor operation: filter

High pass filter

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Application of neighbor operation: terrain analysis on DEM

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Distance measurement

Calculate distance from the given Calculate distance from the given grid cell to source cellgrid cell to source cell same layersame layer global and extend neighbor global and extend neighbor

operationoperation Type of distanceType of distance

nature distancenature distance cost distancecost distance

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Distance measurement: rules

1.414 X Grid Cell

Grid Cell

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Distance measurement: nature distance Unit is grid sizeUnit is grid size TypesTypes Application in ArcViewApplication in ArcView

Continuous Continuous ：： Find DistanceFind Distanceneatestneatest ：： Assign proximityAssign proximity

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Nature distance measurement

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Cost distance measurement

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Cost distance measurement (Cont.) Source matrix, cost matrix and Source matrix, cost matrix and

link cost matrixlink cost matrix Constitution of cost matrix Constitution of cost matrix

sum of different costssum of different costs Link cost matrix calculationLink cost matrix calculation

horizontal: meanhorizontal: mean diagonal: meanX1.414diagonal: meanX1.414

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Cost distance measurement (Cont.): link cost matrix calculation

1 2 12

1 4 15

2 3 67

1 3 44

2 12

4 15

3 67

3

365.7

4.5

4.9 3.5 4.2

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Cost distance measurement (Cont.) Aim: to find minimum accumulative Aim: to find minimum accumulative

cost path cost path Method: loopMethod: loop Example: Example:

Source matrixSource matrix Cost matrixCost matrix Link matrixLink matrix Assign matrixAssign matrix Output matrixOutput matrix

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Minimum accumulative cost measurement

B

A

1 2 12

1 4 15

2 3 67

1 3 44

Source matrix Cost matrix

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Minimum accumulative cost measurement (Cont.)

3

1 2 12

1 4 15

2 67

1 3 44

2.8 3 4.9

2.5 5

3.5 5.72.8

Link matrix

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1.5 B

4.2 1

1.5 2.8

A 2

11.51.52.02.84.2

1 2 12

1 4 15

2 3 67

1 3 44

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1.5 B

4.2 1

1.5 2.8 6.7 4.5

A 2

4

11.51.52.02.84.2

1.51.52.02.84.0

6.74.5

1 2 12

1 4 15

2 3 67

1 3 44

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3.5 1.5 B

3 5.7 4.0 1

1.5 2.8 6.7 4.5

A 2

1.51.52.02.84.0

4.56.7

2.02.8

4.0

5.74.5

6.7

3.03.5

1 2 12

1 4 15

2 3 67

1 3 44

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3.5 1.5 B

3 5.7 4.0 1

1.5 2.8 6.7 4.5

A 2 5.5

2.8

4.0

5.7

4.5

6.7

3.03.5

1 2 12

1 4 15

2 3 67

1 3 44

2.02.8

4.0

5.74.5

6.7

3.03.5

5.5

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3.5 1.5 B

3 5.7 4.0 1

1.5 2.8 6.7 4.5

A 2 5.5

2.8

4.0

5.7

4.5

6.7

3.03.5

1 2 12

1 4 15

2 3 67

1 3 445.5

4.0

5.7

4.5

6.7

3.03.5

5.5

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4 3.5 1.5 B

3 5.7 4.0 1

1.5 2.8 6.7 4.5

A 2 5.5

1 2 12

1 4 15

2 3 67

1 3 44

4.0

5.7

4.5

6.7

3.03.5

5.5

4.0

5.5

4.5

6.7

3.5

5.5

5.5

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4 3.5 1.5 B

3 5.7 4.0 1

1.5 2.8 6.7 4.5

A 2 5.5 9.5

3 1 1 B

3 5 1 7

3 4 8 7

A 5 5 7

1

23

4

5

6 78

Minimum accumulative cost matrix

Cell assign matrix

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Minimum accumulative cost in ArcView

CostDistance:CostDistance:

aGrid.CostDistanceaGrid.CostDistance

(costGrid,DirectionFN, allocationFN, (costGrid,DirectionFN, allocationFN, maxDistance)maxDistance)

CostPathCostPath

aGrid.CostPathaGrid.CostPath

(distanceGrid, directionGrid, (distanceGrid, directionGrid, ByZone)ByZone)

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Zonal

Zonal function operats on Zonal function operats on properties of the region (or zone) properties of the region (or zone) to which a give cell beloges to which a give cell beloges

These properties might be These properties might be length area or shapelength area or shape number of location having a certain number of location having a certain

attribute value on one grid that attribute value on one grid that occurs within the area define by a occurs within the area define by a region on another gridregion on another grid

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Zonal function in ArcView Single gridSingle grid

Map CalculatorMap Calculator aGrid.ZonalGeometry (aGridGeomDescEnum)aGrid.ZonalGeometry (aGridGeomDescEnum)Area of a zone: Area of a zone: #GRID_GEOMDESC_AREA #GRID_GEOMDESC_AREA Perimeter of a zone: #GRID_GEOMDESC_PERIMETER Perimeter of a zone: #GRID_GEOMDESC_PERIMETER Thickness of a zone :Thickness of a zone : #GRID_GEOMDESC_THICKNESS#GRID_GEOMDESC_THICKNESSCharacteristics of an ellipse that is fit to a zone :Characteristics of an ellipse that is fit to a zone : #GRID_GEOMDESC_CENTROID #GRID_GEOMDESC_CENTROID

Only be useful to reclassify raster dataOnly be useful to reclassify raster data Requirement outcome of function is to Requirement outcome of function is to

return a corresponding parameter gridreturn a corresponding parameter grid

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Zonal function in ArcView (Cont.)

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Zonal function in ArcView (Cont.) Multilayer Multilayer

Input: statistics of grid data, Input: statistics of grid data, 分带格网分带格网Output: classify table, histogram, area Output: classify table, histogram, area

statisticsstatistics

Steps: Steps:

Summarize Zones Summarize Zones

Histogram by Zone Histogram by Zone

Tabulate Area Tabulate Area

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Zonal function in ArcView (Cont.)According to drainage area to stat. rainfallAccording to drainage area to stat. rainfall

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Zonal function in ArcView (Cont.)

Documents

Lecture 5 Raster Data Analysis. 2015-10-19 2 Introduction Analysis with raster data is simple and efficient for it’s feature based on position Analysis