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MapCalc MapCalc Cross-Reference: Analysis Operations for
ArcGIS GRID/Spatial Analyst and ERDAS Imagine |
Understanding Spatial Patterns and Relationships ( |
MapCalc Organization and Cross-Reference of Analysis Operations for
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Organization of
MapCalc Analysis Operations
All
·
Reclassifying maps—operations
CLUMP, CONFIGURE, RENUMBER, SIZE, and SLICE
·
Overlaying maps—operations
COMPOSITE, COMPUTE, CALCULATE, COVER, CROSSTAB and INTERSECT
·
Measuring distance and connectivity—operations
DRAIN, RADIATE,
·
Characterizing neighborhoods—operations
INTERPOLATE, ORIENT, PROFILE, SCAN and SLOPE
·
Statistical relationships—operations
ANALYZE, CLUSTER, COMPARE, CORRELATE, REGRESS and RELATE.
This organizational scheme is based on the user's perspective of
map input and output contents—what the map(s) look like going in, and coming
out.
RECLASSIFYING operations assign new values to each map
category on an existing map layer. Regardless
whether you RENUMBER, SLICE, SIZE, CLUMP or CONFIGURE, the resulting map will
have the same "boundaries" (spatial arrangement) as the input
map. The new values might be ones you
directly assigned (RENUMBER), or the ones the computer automatically assigns
(SLICE), or ones based on the area of each category (SIZE), or ones indicating
the shape of the individual features (CONFIGURE). If the same value is assigned to two adjacent
categories, the boundary disappears. In
CLUMP, if a feature is composed of several discrete groupings, each will each
get a different value and the individual boundaries will be distinct. However, in all RECLASSIFYING operations, the
similarities in the spatial arrangement of features on the input and output
maps are readily apparent—just a different set numbers.
OVERLAYING operations are radically different as
they assign new values based on the independent values on two or more
maps. Commands COMPUTE/CALCULATE (with
map variables), COVER and INTERSECT overlay maps on a
"point-by-point" (cell-by-cell) basis. In each instance, an entirely different
looking map is generated as output.
"Region-wide" overlay, on the other hand, results in a map
with similar spatial arrangement of features as those on the
"template" map. The map
categories on the template map identify the locations (cells) whose values from
the "data map" are summarized.
For example, the command “COMPOSITE Districts_map With Slope_map
Average For Avg_Slope” creates a map of the average slope for each district. The result is a map with the same spatial
arrangement of features—just new values.
The effect is similar to a RECLASSIFY, but two input maps are required.
DISTANCE MEASUREMENT operations assign values as a
function of simple or weighted connections among locations. In each instance, a map of
"starter" locations is converted into a map characterizing their
connectivity to their surroundings. The
connections can be "simple," or "weighted" by intervening
conditions. The SPREAD (proximity), and
NEIGHBORHOOD operations assign values that summarize
conditions within the vicinity of map locations (i.e., "roving
window"). In the case of SLOPE,
ORIENT and PROFILE commands, the summary implies a characteristic of a surface,
or gradient map. In the case of
INTERPOLATE or SCAN, the summary is a mathematical or statistical summary of
the values within the neighborhood.
STATISTICAL operations assign values as a function of
the statistical relationships among maps.
In the case of ANALYZE descriptive statistics are reported for a stack
of map layers. In the case of CORRELATE
and REGRESS the spatial relationship among maps is reported in tabular and
equation form. CLUSTER and RELATE generate a new map that shows the similarity
among and within maps, respectively.
COMPARE produces maps and tabular comparisons between maps.
Cross-Reference to GRID/SA Operations (by ESRI)
GRID is a raster geo-processing toolbox that was integrated with the
ARC/
RECLASSIFY OPERATIONS:
New values are assigned as a function of the initial value, size, shape,
or contiguity of each map category on a map.
·
CLUMP -- MapCalc operation that assigns new values to contiguous groups
of cells within each map category.
Related GRID commands are
Shape Analysis function REGIONGROUP
Hydrologic functions
STREAMLINK,STREAMORDER
·
COMPUTE (one map) -- MapCalc operation that assigns new values to each
map location as the mathematical or statistical function of the existing
value. Related GRID commands are
Arithmetic operator UNARY-
Boolean operator ^
Bitwise operators <<,>>,^^
Assignment operator =
Trigometric operators ACOS, ACOSH, ASIN,
ASINH, ATAN, ATAN2, ATANH, COS, COSH, SIN, SINH, TAN, TANH
Expodential and Logarithmic operators EXP,
EXP10,EXP2, LN, LOG10, LOG2, POW, SQR, SQRT
Selection functions SELECT, TEST
Statistical functions EQUALTO,
GREATERTHAN, LESSTHAN, LPOS, UPOS
Other functions ABS, CEIL, CON, FLOAT,
FLOOR, INT, INSUL, MERGE, PICK,
·
CONFIGURE -- MapCalc operation that assigns new values characterizing the
shape of the area associated with each category. Related GRID commands are
None, but shape statistics can be derived
from ARC/INFO tables through user defined scripts
·
RENUMBER -- MapCalc operation that assigns new values to the categories on
a map. Related GRID commands are
Reclassification function RECLASS
·
SIZE -- MapCalc operation that assigns new values according to the
size of the area associated with each map category. Related GRID commands are
Zonal functions
ZONALAREA,ZONALPERIMETER,ZONALTHICKNESS
·
SLICE -- MapCalc operation that assigns new values by dividing the
range of values on a map into specified intervals (contouring). Related GRID commands are
Reclassification function SLICE
OVERLAY OPERATIONS:
New values are assigned as a function of the independent values
associated with each map location or categories on two or more existing maps.
·
COMPOSITE -- MapCalc operation that creates a map summarizing values from
one map that coincide with the categories of another. Related GRID commands are
Zonal functions
ZONALFILL, ZONALMAX, ZONALMEAN,
ZONALMIN, ZONALRANGE, ZONALSTD, ZONALSUM, ZONALVARIETY
·
COMPUTE (two or more maps) -- MapCalc operation that creates a map as the
mathematical or statistical function of two or more maps. Related GRID commands are
Arithmetic operators *, +, -, DIV, MOD
Boolean operators !, &, |
Relational operators <, <=, ==,
>, >=, ^=
Bitwise operators !!, &&, ||
Combinatorial operators CAND, COR, CXOR
Logical operators
Statistical functions MAJORITY, MAX, MED,
MIN, MINORITY, RANK, REGRESSION, VARIETY
Other function FMOD
·
COVER -- MapCalc operation that creates a new map where non-zero values
of the top map replace the values on the previous (bottom) map, or stack of
maps. Related GRID commands are
Selection functions SELECTBOX,
SELECTCIRCLE, SELECTMASK, SELECTPOINT, SELECTPOLYGON
·
INTERSECT -- MapCalc operation that creates a map by assigning new values
to pair wise combinations of the values on two maps. Related GRID commands are
Combinatorial function COMBINE
DISTANCE OPERATIONS:
New values are assigned as a function of the simple or effective distance,
optimal movement, narrowness, or visual connectivity among map locations.
·
DRAIN -- MapCalc operation that creates a map indicating the number of
steepest paths (optimal path density) from a set of locations along a
surface. Related GRID commands are
Hydrologic function FLOWACCUMULATION
·
RADIATE -- MapCalc operation that creates a map indicating areas that are
visible from specified locations.
Related GRID commands are
Visibility tools VISENCODE, VISIBILITY
·
SPAN -- MapCalc operation that creates a map indicating the narrowness
within areas associated with each category of a map. Related GRID commands are
None
·
SPREAD -- MapCalc operation that creates a map indicating the shortest
effective distance from specified cells to all other locations. Related GRID commands are
Distance functions CORRIDOR (compute sum),
COSTALLOCATION (slice), COSTDISTANCE, EUCALLOCATION, EUDIRECTION (orient),
EUCDISTANCE
Shape Analysis functions EXPAND, SHRINK
Hydrologic function WATERSHED, BASIN
·
STREAM -- MapCalc operation that creates a map identifying the steepest
downhill route along a surface (optimal path).
Related GRID commands are
Distance functions COSTBACKLINK, COSTPATH,
PATHDISTANCE
Hydrologic function FLOWDIRECTION (orient)
NEIGHBORHOOD OPERATIONS:
New values are assigned as a function of the independent values within a
specified distance and direction around each map location.
·
INTERPOLATE -- MapCalc operation that creates a continuous surface from point
data. Related GRID commands are
Surface functions IDW, KRIGING, SPLINE,
TREND
·
ORIENT -- MapCalc operation that creates a map indicating aspect along a
continuous surface. Related GRID
commands are
Surface function ASPECT
Distance function EUCDIRECTION
·
PROFILE -- MapCalc operation that creates a map indicating the
cross-sectional profile along a continuous surface. Related GRID commands are
Surface functions SAI, SHADE
·
SCAN -- MapCalc operation that creates a map summarizing the values
that occur within the vicinity of each cell.
Related GRID commands are
Conditional statement IF, WHILE, DOCELL
summaries within a DOCELL block using Accumulative operators *=, +=, -=, /=,
{=, }= and/or Assignment operator :=
Statistical operation POPULARITY
Focal functions FOCALFLOW, FOCALMAX,
FOCALMEAN, FOCALMIN, FOCALRANGE,
FOCALSTD, FOCALSUM, FOCALVARIETY
Data Clean-up functions BOUNDARYCLEAN,
MAJORITYFILTER, NIBBLE, THIN
Hydrologic functions FILL, SINK
·
SLOPE -- MapCalc operation that creates a map indicating the slope (1st
derivative) along a continuous surface.
Related GRID commands are
Surface function SLOPE
STATISTICAL OPERATIONS:
New values and statistical summaries are assigned as a function of the
numerical relationships among maps.
·
ANALYZE -- MapCalc operation that creates a map of the simple or weighted
average, standard deviation, coefficient of variation and several other
descriptive statistics for two or more maps (map stack). Related GRID commands are
STACKSTATS
MEAN (simple average only), MIN, MAX, MED,
VARIETY, MAJORITY, MINORITY, RANGE
·
CLUSTER -- MapCalc operation that creates a map that identifies areas
with similar data patterns (characteristics) using a stack of input map
layers. Related GRID commands are
ISOCLUSTER
MLCLASSIFY (maximum-likelihood
classification)
·
COMPARE -- MapCalc operation that generates a summary table of various
comparison statistics between two maps.
Related GRID commands are
DIFF (determines which values are
logically different)
Comparative statistics can be derived by
evaluating index equations using GRIDMATH
·
CORRELATE -- MapCalc operation that generates a correlation matrix from a
stack of maps. Related GRID commands are
CORRELATION for a single pair of map
layers
·
REGRESS -- MapCalc operation performs a linear regression analysis by
using the "least squares" method to fit a line through a set of data
points in multiple maps (map stack) and outputs the regression coefficients of
the prediction model. Related GRID
commands are
REGRESSION (Linear | Logistic)
·
RELATE -- MapCalc operation that creates a map that quantifies the
similarity of each location on a map to an evaluation data pattern, or set of
comparison values. Related GRID commands
are
None
Cross-Reference to
ERDAS Imagine Operations (by ERDAS/Leica)
Imagine is a powerful image mapping
and visualization package with a robust set of grid-based map analysis
tools. Its historical roots are in
remote sensing and image processing and has particularly well-developed
statistical operations.
RECLASSIFY OPERATIONS:
New values are assigned as a function of the initial value, size, shape,
or contiguity of each map category on a map.
·
CLUMP -- MapCalc operation that assigns new values to contiguous groups
of cells within each map category.
Related ERDAS commands are
CLUMP
SIEVE- deletes clumps smaller than user
specified
ELIMINATE- similar to Sieve but dissolves
smaller clumps into neighbors.
·
COMPUTE (one map) -- MapCalc operation that assigns new values to each
map location as the mathematical or statistical function of the existing
value. Related ERDAS commands are
RECODE
Trigometric
operators: ACOS, ASIN, ATAN,
Expodential and
Logarithmic operators: LOG, LN, SQRT
Other functions: Row, pi,
modabs, int, even, odd, max, min, convert units, format string/number,
lowercase, uppercase
SINGLE INPUT ‘FUNCTIONS’
Trigometric operators: ACOS, ACOSH,
ASIN, ASINH, ATAN, COS, COSH, SIN, SINC, SINH, TAN, TANH
Expodential and
Logarithmic operators: EXP, LOG, LOG10, SQRT
Other functions: ABS, ANGLE,
BINARY, CEIL, CONJ, DELTA, EVEN, GAMMA, IMAG, INV, ODD, REAL, RECT, ROUND,
SIGN, STEP, TRI, TRUNC, WHOLE
·
CONFIGURE -- MapCalc operation that assigns new values characterizing the
shape of the area associated with each category. Related ERDAS commands are
PERIMETER
·
RENUMBER -- MapCalc operation that assigns new values to the categories on
a map. Related ERDAS commands are
RECODE
Trigometric
operators: ACOS, ASIN, ATAN,
Expodential and
Logarithmic operators: LOG, LN, SQRT
Other functions: Row, pi,
modabs, int, even, odd, max, min, convert units, format string/number,
lowercase, uppercase
SINGLE INPUT ‘FUNCTIONS’
Trigometric operators: ACOS, ACOSH,
ASIN, ASINH, ATAN, COS, COSH, SIN, SINC, SINH, TAN, TANH
Expodential and
Logarithmic operators: EXP, LOG, LOG10, SQRT
Other functions: ABS, ANGLE,
BINARY, CEIL, CONJ, DELTA, EVEN, GAMMA, IMAG, INV, ODD, REAL, RECT, ROUND,
SIGN, STEP, TRI, TRUNC, WHOLE
·
SIZE -- MapCalc operation that assigns new values according to the
size of the area associated with each map category. Related ERDAS commands are
Size of each value is always present in
‘Histogram’ column of every image (mandatory)
CLUMP
(reports clump pixel size)
·
SLICE -- MapCalc operation that assigns new values by dividing the
range of values on a map into specified intervals (contouring). Related ERDAS commands are
TOPOGRAPHIC LEVEL SLICE (refers to DEM,
but any raster is fine)
OVERLAY OPERATIONS:
New values are assigned as a function of the independent values
associated with each map location or categories on two or more existing maps.
·
COMPOSITE -- MapCalc operation that creates a map summarizing values from
one map that coincide with the categories of another. Related ERDAS commands are
ZONAL ATTRIBUTES (Raster summary of Vector
regions, must have template in Vector)
·
COMPUTE (two or more maps) -- MapCalc operation that creates a map as the
mathematical or statistical function of two or more maps. Related ERDAS commands are
TWO INPUT ‘OPERATORS’
Add, subtract,
Multiplication, Division, Power and MOD
INDEX
·
COVER -- MapCalc operation that creates a new map where non-zero values
of the top map replace the values on the previous (bottom) map, or stack of
maps. Related ERDAS commands are
OVERLAY (you specify if min or max value
of each cell in the two layers takes priority)
Combined with Recode command allows same
functionality with several steps i.e. masking data
·
INTERSECT -- MapCalc operation that creates a map by assigning new values
to pair wise combinations of the values on two maps. Related ERDAS commands are
MATRIX
DISTANCE OPERATIONS:
New values are assigned as a function of the simple or effective
distance, optimal movement, narrowness, or visual connectivity among map
locations.
·
DRAIN -- MapCalc operation that creates a map indicating the number of
steepest paths (optimal path density) from a set of locations along a
surface. Related ERDAS commands are
None
·
RADIATE -- MapCalc operation that creates a map indicating areas that are
visible from specified locations.
Related ERDAS commands are
Viewshed Analysis
·
SPAN -- MapCalc operation that creates a map indicating the narrowness
within areas associated with each category of a map. Related ERDAS commands are
None
·
SPREAD -- MapCalc operation that creates a map indicating the shortest
effective distance from specified cells to all other locations. Related ERDAS commands are
SEARCH
(Euclidean distance only)
·
STREAM -- MapCalc operation that creates a map identifying the steepest
downhill route along a surface (optimal path).
Related ERDAS commands are
None
NEIGHBORHOOD OPERATIONS:
New values are assigned as a function of the of the independent values
within a specified distance and direction around each map location.
·
INTERPOLATE -- MapCalc operation that creates a continuous surface from point
data. Related ERDAS commands are
3-D Surfacing
·
ORIENT -- MapCalc operation that creates a map indicating aspect along a
continuous surface. Related ERDAS
commands are
ASPECT
·
PROFILE -- MapCalc operation that creates a map indicating the
cross-sectional profile along a continuous surface. Related ERDAS commands are
None but might be possible using Spatial
Modeler
·
SCAN -- MapCalc operation that creates a map summarizing the values
that occur within the vicinity of each cell.
Related ERDAS commands are
NEIGHBORHOOD: Sum, Diversity, Density,
Majority, Minority, Max, Min, Rank
·
SLOPE -- MapCalc operation that creates a map indicating the slope (1st
derivative) along a continuous surface.
Related ERDAS commands are
SLOPE
STATISTICAL OPERATIONS:
New values and statistical summaries are assigned as a function of the
numerical relationships among maps.
·
ANALYZE -- MapCalc operation that creates a map of the simple or weighted
average, standard deviation, coefficient of variation and other descriptive
statistics for two or more maps (map stack).
Related ERDAS commands are
Modeler Functions: STATISTICAL (not
available via a ‘button’)
·
CLUSTER -- MapCalc operation that creates a map that identifies areas
with similar data patterns (characteristics) using a stack of input map
layers. Related ERDAS commands are
CLASSIFIERà Unsupervised (ISODATA)
·
COMPARE -- MapCalc operation that generates a summary table of various
comparison statistics between two maps.
Related ERDAS commands are
Modeler Functions: CONDITIOAL (compare
using conditional statements; not available via a ‘button’)
·
CORRELATE -- MapCalc operation that generates a correlation matrix from a
stack of maps. Related ERDAS commands
are
Modeler Functions: ANALYSISà Correlation
·
REGRESS -- MapCalc operation performs a linear regression analysis by
using the "least squares" method to fit a line through a set of data
points in multiple maps (map stack) and outputs the regression coefficients of
the prediction model. Related ERDAS
commands are
None
·
RELATE -- MapCalc operation that creates a map that quantifies the
similarity of each location on a map to an evaluation data pattern, or set of
comparison values. Related ERDAS
commands are
None