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Table Of Contents

  1. Docs
  2. Features
  3. Geospatial Features
  4. Web Map Service

Web Map Service

Overview

Kinetica provides a Web Map Service (WMS) for generating image tiles from the geospatial data contained in it. The type of image tiles returned, the data used to generate the tiles, and the graphical styles in the tiles are specified in the query string of the WMS call. These would typically be used as overlays on top of a map. Examples of this can be seen in the demo that comes bundled with Kinetica at http://<host>:8080/gaiademo. Any table with x,y coordinates or WKT shapes can be used as the source for generating images.

Note that the cb_raster and raster styles have a GEO_ATTR parameter that allows specifying the name of a geometry (WKT) column to use during rendering. This parameter is optional as Kinetica will automatically find a geometry column, but if there's multiple geometry columns and a specific column needs to be used, GEO_ATTR is necessary. If the specified GEO_ATTR column exists and is a geometry-type column, Kinetica will continue with rendering. If the column does not exist or it is not a geometry-type column, Kinetica will try to process the column as point or track data instead.

Important

If GEO_ATTR is not specified and there's more than one geometry column, Kinetica will attempt to process the columns as point or track data.

The requested image is then returned in the HTTP response message body.

As the isochrones mode utilizes some of the contour and labels modes' parameters as well as some of the /solve/graph endpoint's parameters, the same usage guidelines apply. Review Contour, Labels, and Solving a Graph for more information.

Downloads

The examples below use the following tables:

Required Parameters

The following parameters are required in all WMS calls:

Name Description Allowable Values
REQUEST WMS Request
  • GetMap for getting an image
  • GetCapabilities is also supported
SRS Spatial Reference System (i.e. EPSG code)
  • Plate Carree projection codes: PLATE_CARREE, EPSG:4326
  • Web Mercator projection codes: WEB_MERCATOR, 900913, EPSG:900913, 102100, EPSG:102100, 3857, EPSG:3857
LAYERS The requested image layer(s) One or more comma-separated table names
BBOX Geographic bounding box as a comma-separated list of: min_longitude, min_latitude, max_longitude, max_latitude Four comma-separated numerics
WIDTH Image width, in pixels; best performance if a power of 2 64 - 8192
HEIGHT Image height, in pixels; best performance if a power of 2 64 - 8192

Optional Parameters

The following parameters are optional for WMS calls:

Name Description Allowable Values Default Value
VERSION WMS Version--only v1.1.1 is supported 1.1.1 1.1.1
STYLES The mode of image requested
  • raster
  • cb_raster
  • heatmap
  • contour
  • labels
  • isochrones
 raster
FORMAT Output image format--only PNG is supported image/png image/png
TRANSPARENT Controls background transparency of the generated image
  • TRUE for transparent background
  • FALSE for opaque background
 TRUE
X_ATTR Name of the column to be used as the longitude Numeric column from LAYERS source table list; must be of int, double, float, or long column type Column x
Y_ATTR Name of the column to be used as the latitude Numeric column from LAYERS source table list; must be of int, double, float, or long column type Column y
GEO_ATTR The WKT attribute used to render the raster/cb_raster (particularly if you have more than one WKT column in the table) A WKT column name  
SYMBOL_ATTR The symbol attribute used to render symbols in lieu of the default SYMBOLCODE column. See DOSYMBOLOGY. Supports expressions, e.g., if(), case(), etc. A string column containing symbol IDs Column SYMBOLCODE

Modes

The following modes are supported, as specified by the STYLES parameter:

Descriptions of each mode along with the mode-specific parameters can be found below.

RASTER

The raster mode is used to rasterize points, shapes, symbols, and/or tracks from one or more tables. Available parameters are:

Name Description Allowable Values Default Value
ANTIALIASING Set to TRUE to enable anti-aliasing, which will smoothen WKT LINESTRING and POLYGON outlines TRUE or FALSE FALSE
DOPOINTS Rasterize point data toggle TRUE or FALSE TRUE
DOSHAPES Rasterize shapes toggle TRUE or FALSE TRUE
DOSYMBOLOGY Rasterize symbols toggle. When set to TRUE, Kinetica will automatically look for a SYMBOLCODE column in the specified table that contains strings that match inserted symbols TRUE or FALSE FALSE
DOTRACKS Rasterize tracks TRUE or FALSE TRUE
HASHLINEANGLES Clockwise rotation angle from a perpendicular hash line in degree Real numbers 0
HASHLINECOLORS RBG color values in hex for the hash lines Hex color (or -1 for same color as shapeline) SHAPELINECOLOR value
HASHLINEINTERVALS Distance between the center points of hash lines in pixels Positive integers 20
HASHLINELENS Length of hash lines in pixels. Inputting a 0 disables hash lines Non-negative integers 0
HASHLINEWIDTHS Width of hash lines in pixels Positive integers 3
ORDER_LAYERS Enables layers to be rendered in the order they were specified in true or false  
POINTCOLORS Color of points Hex color FF0000 (red)
POINTOFFSET_X Horizontal offset for point location in pixels Signed integers 0
POINTOFFSET_Y Vertical offset for point location in pixels Signed integers 0
POINTSHAPES Shape of points
  • none
  • circle
  • square
  • diamond
  • hollowcircle
  • hollowsquare
  • hollowdiamond
  
POINTSIZES Size of points 0 - 20 3
SHAPEFILLCOLORS Fill color for closed shapes (i.e. polygons) Hex color (or -1 for no fill) -1 (no fill)
SHAPELINECOLORS Line colors for shapes Hex color FFFF00 (yellow)
SHAPELINEPATTERNLENS Lengths of dashed-line patterns in number of bits 1 - 64 0
SHAPELINEPATTERNS Bitmaps representing dashed-line patterns; bits of 1 enable the pixels associated with them, but if all bits are 0, dashed-line drawing is disabled, i.e. solid lines are drawn Unsigned 64-bit (hexadecimal) integers 0
SHAPELINEWIDTHS Line widths of shapes 0 - 20 3
SYMBOLROTATIONS Angle in degree for clockwise symbol rotation Numeric constants or expressions (including column names)  
TRACKHEADCOLORS Color of track head markers Hex color FFFFFF (white)
TRACKHEADSHAPES Shape of track head markers
  • none
  • circle
  • square
  • diamond
  • hollowcircle
  • hollowsquare
  • hollowdiamond
 circle
TRACKHEADSIZES Size of track head markers 0 - 20 10
TRACKLINECOLORS Line colors for tracks Hex color 00FF00 (green)
TRACKLINEWIDTHS Line widths of tracks 0 - 20 (0: don't draw the track lines) 3
TRACKMARKERCOLORS Color of track point markers Hex color 0000FF (blue)
TRACKMARKERSHAPES Shape of track point markers
  • none
  • circle
  • square
  • diamond
  • hollowcircle
  • hollowsquare
  • hollowdiamond
  • SYMBOLCODE (to specify a symbol)
 none
TRACKMARKERSIZES Size of track point markers 0 - 20 2

Important

The WORLDLAYERS parameter can be used if the table(s) specified in the LAYERS parameter only have a subset of all track points and the desired behavior is to render the entire track. In this case the unique track ids existing in the LAYERS table(s) will be identified, but the actual track points will be pulled from the WORLDLAYERS table(s).

Styling parameters must be specified for each table provided in the LAYERS parameter. For instance, if LAYERS=LAYER1,LAYER2 then to set different point colors for each layer the syntax would be: POINTCOLORS=FF0000,0000FF. In this case points from LAYER1 would be rendered as red while points from LAYER2 would be rendered as blue. If styling parameters are not provided for a layer, the default value is applied.

All colors must be provided in hex notation in the format RRGGBB or AARRGGBB (to specify the alpha value). For example, opaque red may be given as FF0000 or FFFF0000.

To use symbols rather than points, the source table(s) must have a string type column named SYMBOLCODE, which contains the desired symbol's identifier. All necessary symbols need to be added via the /insert/symbol endpoint. The IDs in the SYMBOLCODE column must match up with the IDs of the inserted symbols. To use a non-default column for symbols or to change a symbol conditionally, use the SYMBOL_ATTR parameter. For example, you can change the displayed symbol conditionally depending on a record's vendor_id using the following SYMBOL_ATTR statement:

SYMBOL_ATTR=case(vendor_id,{'YCAB','NYC'},{'taxi_blue','taxi_green'},'taxi_black')

Note

Labels (using the labels style) and WKT shapes cannot be rendered in the same WMS call. Both can be shown on the same map by creating separate map layers, each with its own WMS call.

For example, to generate a raster image from a table nyc_neighborhood with the following characteristics:

  • SRS is EPSG:4326
  • Bounding box longitude is from -74.1 to -73.9 and latitude is from 40.6 to 40.9
  • Image size is 1024 x 1024
  • The geometry column used to render the raster image is geom
  • The raster image will render shapes because DOSHAPES is set to TRUE
http://${HOSTNAME}:9191/wms?REQUEST=GetMap
&SRS=EPSG:4326
&LAYERS=nyc_neighborhood
&BBOX=-74.1,40.6,-73.9,40.9
&WIDTH=1024
&HEIGHT=1024
&STYLES=raster
&GEO_ATTR=geom
&DOSHAPES=TRUE

To generate a raster image from a table flights with the following characteristics:

  • SRS is EPSG:4326
  • Bounding box longitude is from -180 to 180 and latitude is from -90 to 90
  • Image size is 512 by 512
  • Track rendering is enabled
  • Track headers are diamond-shaped
  • Track marker color is set to 006BBB
  • Track markers are square-shaped
  • Track line color is set to 80858E
http://${HOSTNAME}:9191/wms?REQUEST=GetMap
&SRS=EPSG:4326
&LAYERS=flights
&BBOX=-180,-90,180,90
&WIDTH=512
&HEIGHT=512
&STYLES=raster
&DOTRACKS=1
&TRACKHEADSHAPES=diamond
&TRACKMARKERCOLORS=006BBB
&TRACKMARKERSHAPES=square
&TRACKLINECOLORS=80858E

To generate a raster image with the following characteristics using information from a table nyctaxi and symbols generated from a taxi icon SVG file:

Important

The SYMBOL_ATTR statement below references three symbols: taxi_green, taxi_blue, and taxi_default. Symbols are created in Kinetica using an SVG path or raw bytes reprsenting an SVG file via /insert/symbol. In this example, the symbols are created using an SVG path extracted from the taxi.svg file which is then placed in the SVG_PATH variable.

curl -sS -X POST --header "Content-Type: application/json" \
--user ${USERNAME}:${PASSWORD} \
--data '{"symbol_id":"taxi_green", "symbol_format":"svg_path", "symbol_data":"'${SVG_PATH}'", "options":{"color":"00FF00"}}' \

curl -sS -X POST --header "Content-Type: application/json" \
--user ${USERNAME}:${PASSWORD} \
--data '{"symbol_id":"taxi_blue", "symbol_format":"svg_path", "symbol_data":"'${SVG_PATH}'", "options":{"color":"FF0000"}}' \
http://${HOSTNAME}:9191/insert/symbol

curl -sS -X POST --header "Content-Type: application/json" \
--user ${USERNAME}:${PASSWORD} \
--data '{"symbol_id":"taxi_default", "symbol_format":"svg_path", "symbol_data":"'${SVG_PATH}'", "options":{"color":"0000FF"}}' \
http://${HOSTNAME}:9191/insert/symbol
  • SRS is PLATE_CARREE
  • Bounding box longitude is from -73.99120 to -73.99115 and latitude is from 40.750300 to 40.750350
  • Image size is 512 by 512
  • The x attribute is set to the dropoff_longitude column value from the source table
  • The y attribute is set to the dropoff_latitude column value from the source table
  • Symbology rendering is enabled
  • The symbol attribute is set using a series of if statements:
    • If total_amount is less than or equal to 20 but greater than 10, set the symbol to taxi_green
    • If total_amount is greater than 20, set the symbol to taxi_blue
    • If total_amount is less than 10, set the symbol to taxi_default
http://${HOSTNAME}:9191/wms?REQUEST=GetMap
&SRS=PLATE_CARREE
&LAYERS=nyctaxi
&BBOX=-73.99120,40.750300,-73.99115,40.750350
&WIDTH=512
&HEIGHT=512
&STYLES=raster
&X_ATTR=dropoff_longitude
&Y_ATTR=dropoff_latitude
&DOSYMBOLOGY=TRUE
&SYMBOL_ATTR=if(total_amount<=20%20and%20total_amount>10,'taxi_green',if(total_amount>20,'taxi_blue','taxi_default'))

CB_RASTER

The class break raster mode is for generating class break renderings. A class break rendering is the rasterization of the data from one or more tables with styling applied on a per-class basis. Distinct values (for strings) or ranges (for numeric columns) must be provided in the CB_VALS parameter.

Important

All RASTER mode parameters except SYMBOLROTATIONS and ORDER_LAYERS can be used with the CB_RASTER mode in addition to the parameters listed below

Name Description Allowable Values Default Value
CB_ATTR Class break attribute (Required) Any column from the LAYERS source table list  
CB_VALS

Values or ranges to apply for the class break (Required)

NOTE: The starting value of the range is inclusive and the end value is exclusive

List of values or ranges separated by CB_DELIMITER (e.g., 0:5,5:10,15:30)

This specifies three ranges:

0  up to but not including 5
5  up to but not including 10
15 up to but not including 30
 
CB_DELIMITER A group of characters which separate values or ranges in CB_VALS. Default value is , Alpha-numeric or special characters ,
ORDER_CLASSES Enables classes to be rendered in the order they were specified TRUE or FALSE FALSE
USE_POINT_RENDERER

Set to TRUE to render points larger than 1 pixel; if FALSE, all points will be 1 pixel.

NOTE: Only used when OpenGL rendering is disabled

 TRUE or FALSE FALSE
CB_POINTCOLOR_ATTR Class break attribute applied to only the point color. Overrides CB_ATTR when applied Any column from the LAYERS source table list  
CB_POINTCOLOR_VALS

Values or ranges to apply for the CB_POINTCOLOR_ATTR class break

NOTE: The starting value of the range is inclusive and the end value is exclusive

List of values or ranges separated by CB_DELIMITER (e.g., 0:5,5:10,15:30)

This specifies three ranges:

0  up to but not including 5
5  up to but not including 10
15 up to but not including 30
 
CB_POINTSIZE_ATTR Class break attribute applied to only the point size. Overrides CB_ATTR when applied Any column from the LAYERS source table list  
CB_POINTSIZE_VALS

Values or ranges to apply for the CB_POINTSIZE_ATTR class break

NOTE: The starting value of the range is inclusive and the end value is exclusive

List of values or ranges separated by CB_DELIMITER (e.g., 0:5,5:10,15:30)

This specifies three ranges:

0  up to but not including 5
5  up to but not including 10
15 up to but not including 30
 
CB_POINTSHAPE_ATTR Class break attribute applied to only the point shape. Overrides CB_ATTR when applied Any column from the LAYERS source table list  
CB_POINTSHAPE_VALS

Values or ranges to apply for the CB_POINTSHAPE_ATTR class break

NOTE: The starting value of the range is inclusive and the end value is exclusive

List of values or ranges separated by CB_DELIMITER (e.g., 0:5,5:10,15:30)

This specifies three ranges:

0  up to but not including 5
5  up to but not including 10
15 up to but not including 30
 
ALPHA_BLENDING Set to TRUE to enable alpha blending of semi-transparent colors for better rendering of colors when ORDER_CLASSES is set to TRUE. When enabled, alpha blending may affect performance. TRUE or FALSE FALSE

All of the RASTER-mode styling parameters are valid for CB_RASTER (except SYMBOLROTATIONS); however, there must be styling parameters specified for each class. Each entry in CB_VALS connotes an individual class to which styling is applied. If styling parameters are not provided for a class, the default value is applied.

The per-style class break parameters (CB_POINTCOLOR..., CB_POINTSIZE..., and CB_POINTSHAPE...) can be used to override attribute color, size, or shapes if the given data falls into the given range, e.g., enlarge a point's size if its total sales amount was greater than some amount.

The keyword <other> can be used as a value in CB_VALS instead of a class name to render all non-matching classes as specified by corresponding style options. The length of the style options must match the number of classes specified (including <other>).

For example, to generate a category-based class-break raster image from a table nyctaxi with the following characteristics:

  • SRS is PLATE_CARREE
  • Bounding box longitude is from -74.1 to -73.9 and latitude is from 40.6 to 40.9
  • Image size is 1024 x 1024
  • X-axis position is extracted from the nyctaxi table's pickup_longitude column
  • Y-axis position is extracted from the nyctaxi table's pickup_latitude column
  • Passenger count is extracted from the nyctaxi table's passenger_count column
  • Classes are:
    1. Between 1 and 2 passengers -- diamonds colored yellow (999900)
    2. Between 3 and 5 passengers -- circles colored orange (CC6600)
    3. Anything else (as designated by the <other> keyword) -- squares colored red (FF0000)
  • ORDER_CLASSES is enabled, so 999900 will be rendered first, CC6600 will be rendered below that, and FF0000 below that
  • Points have a size of 2
http://${HOSTNAME}:9191/wms?REQUEST=GetMap
&SRS=PLATE_CARREE
&LAYERS=nyctaxi
&BBOX=-74.1,40.6,-73.9,40.9
&WIDTH=1024
&HEIGHT=1024
&STYLES=cb_raster
&X_ATTR=pickup_longitude
&Y_ATTR=pickup_latitude
&CB_ATTR=passenger_count
&CB_VALS=1:3,3:5,<other>
&POINTCOLORS=999900,CC6600,FF0000
&ORDER_CLASSES=true
&POINTSIZES=2
&POINTSHAPES=diamond,circle,square

HEATMAP

The heatmap mode is used to generate a heat map image of one or more tables. Heatmaps are a visual representation of the information contained in the given tables.

Available parameters are:

Name Description Allowable Values Default Value
BLUR_RADIUS Blurring radius for the heat map 1 - 32 5
COLORMAP Colormap for the heat map
  • Perceptually-Uniform - viridis, inferno, plasma, magma
  • Sequential I - Blues, BuGn, BuPu, GnBu, Greens, Greys, Oranges, OrRd, PuBu, PuBuGn, PuRd, Purples, RdPu, Reds, YlGn, YlGnBu, YlOrBr, YlOrRd
  • Sequential II - afmhot, autumn, bone, cool, copper, gist_heat, gray, gist_gray, gist_yarg, binary, hot, pink, spring, summer, winter
  • Diverging - BrBG, bwr, coolwarm, PiYG, PRGn, PuOr, RdBu, RdGy, RdYlBu, RdYlGn, Spectral, seismic
  • Qualitative - Accent, Dark2, Paired, Pastel1, Pastel2, Set1, Set2, Set3
  • Misc - gist_earth, terrain, ocean, gist_stern, brg, CMRmap, cubehelix, gnuplot, gnuplot2, gist_ncar, spectral, nipy_spectral, jet, rainbow, gist_rainbow, hsv, flag, prism
 jet
GRADIENT_START_COLOR Gradient start color for the heat map Hex color 000000 (black)
GRADIENT_END_COLOR Gradient end color for the heat map Hex color 000000 (black)
VAL_ATTR Attribute to use to calculate the data points for the heat map Column from LAYERS source table list; must be of int, double, float, long, or decimal column type. Can invoke several "behaviors"; See below for more information. (none)

For the Heatmap mode in particular, the BBOX parameter defines the geographic area while the WIDTH and HEIGHT parameters define the pixel grid resolution over which the heatmap will be calculated.

If COLORMAP is specified, it will be used regardless of whether GRADIENT_START_COLOR/GRADIENT_END_COLOR are specified. If the given colormap is invalid, an error will be returned. If COLORMAP is blank or unspecified, GRADIENT_START_COLOR/GRADIENT_END_COLOR are used, if specified. If none of these is specified, the jet colormap will be used.

VAL_ATTR can be used to enable special behaviors. A description of the behavior as well as how to enable the behavior can be found below.

  • Count - the number of records at each pixel is used to generate the heatmap
    • If no VAL_ATTR is specified or VAL_ATTR=
    • VAL_ATTR=count(column_name)
  • Sum - the sum of column_name within each pixel is used to generate the heatmap
    • VAL_ATTR=column_name
    • VAL_ATTR=sum(column_name)
  • Average - the average of column_name within each pixel is used to generate the heatmap
    • VAL_ATTR=avg(column_name)
    • VAL_ATTR=mean(column_name)
  • Minimum - the minimum of column_name within each pixel is used to generate the heatmap
    • VAL_ATTR=min(column_name)
  • Maximum - the maximum of column_name within each pixel is used to generate the heatmap
    • VAL_ATTR=max(column_name)

For example, to generate a heatmap image from a table nyctaxi with the following characteristics:

  • SRS is PLATE_CARREE
  • Bounding box longitude is from -80 to -70 and latitude is from 35 to 45
  • Image size is 512 x 512
  • X-axis position is extracted from the nyctaxi table's pickup_longitude column
  • Y-axis position is extracted from the nyctaxi table's pickup_latitude column
  • A blur radius of 5
  • A plasma colormap
http://${HOSTNAME}:9191/wms?REQUEST=GetMap
&SRS=PLATE_CARREE
&LAYERS=nyctaxi
&BBOX=-80,35,-70,45
&WIDTH=512
&HEIGHT=512
&STYLES=heatmap
&BLUR_RADIUS=5
&X_ATTR=pickup_longitude
&Y_ATTR=pickup_latitude
&COLORMAP=plasma

CONTOUR

The contour mode is used to generate a contour plot image of one or more tables. A contour plot is a plane section of the three-dimensional graph of the function z = f(x, y) parallel to the x, y plane. Contour plots contain isolines, which show the location(s) where the data has the same z value.

Available parameters are:

Name Description Allowable Values Default Value
COLORMAP Colormap for the contour or contour grid.
  • Perceptually-Uniform - viridis, inferno, plasma, magma
  • Sequential I - Blues, BuGn, BuPu, GnBu, Greens, Greys, Oranges, OrRd, PuBu, PuBuGn, PuRd, Purples, RdPu, Reds, YlGn, YlGnBu, YlOrBr, YlOrRd
  • Sequential II - afmhot, autumn, bone, cool, copper, gist_heat, gray, gist_gray, gist_yarg, binary, hot, pink, spring, summer, winter
  • Diverging - BrBG, bwr, coolwarm, PiYG, PRGn, PuOr, RdBu, RdGy, RdYlBu, RdYlGn, Spectral, seismic
  • Qualitative - Accent, Dark2, Paired, Pastel1, Pastel2, Set1, Set2, Set3
  • Misc - gist_earth, terrain, ocean, gist_stern, brg, CMRmap, cubehelix, gnuplot, gnuplot2, gist_ncar, spectral, nipy_spectral, jet, rainbow, gist_rainbow, hsv, flag, prism
 jet
COLOR Isoline color to be used when flooded contours are enabled; otherwise isolines will follow the colormap Hex notation in the format RRGGBB or AARRGGBB, in which case the alpha value is used for the transparency of the flooded contours. The line itself is always opaque. FF000000
BG_COLOR Background color Hex notation in the format RRGGBB or AARRGGBB (to specify the alpha value) 00000000 (transparent)
TEXT_COLOR Color of labels text Hex notation in the format RRGGBB or AARRGGBB (to specify the alpha value) FF000000
MIN_LEVEL Minimum isoline value to be shown. Number -1
MAX_LEVEL Maximum isoline value to be shown. Number -1
NUM_LEVELS Number of equally-separated isolines to be shown. 10 or greater 10
ADJUST_LEVEL Recompute the minimum and maximum levels based on the current data in the viewport. Setting this will ignore the values of MIN_LEVEL and MAX_LEVEL. Number 1
VAL_ATTR Attribute to use to calculate the isolines. Column from LAYERS source table list; must be of int, double, float, long, or decimal column type. Can invoke several "behaviors"; See below for more information. z
SEARCH_RADIUS Neighborhood of influence of sample data (in percent of the image/grid). See below for more information. Number 1
GRIDDING_METHOD Methods to produce a regularly-spaced, rectangular array of values from potentially irregularly-spaced XY-val data. See below for more information.
  • INV_DST_POW -- Inverse Distance to a Power; a weighted average interpolator that can either be an exact or a smoothing interpolator
 INV_DST_POW
SMOOTHING_FACTOR Amount of smoothing of the contribution of neighboring points. Number between 0 and 1 0.01
MAX_SEARCH_CELLS Maximum number of cells to use once the SEARCH_RADIUS has been converted from percentage to cells. The higher the number, the higher the quality of the contour plot. Number 100
RENDER_OUTPUT_GRID Show the grid used to build the contour plot, which is equivalent to generating a flooded-contour. This affects the labels by clipping the area around them. The opacity of the flooded-contours is specified in COLOR. 0 (false) or 1 (true) 0
GRID_SIZE Number of subdivisions along the x axis when building the grid. The y axis will be set according to the aspect ratio. Number 100
ADJUST_GRID Allows the grid size and search radius to be automatically varied based on the current data in the viewport. 0 (false) or 1 (true) 0
ADJUST_GRID_NEIGH Used to estimate the clustering of the data (k-means) when ADJUST_GRID is set to 1. Clustering estimation is capped by MAX_SEARCH_CELLS. Number between 0 and 1 1
ADJUST_GRID_SIZE Size of the sampling grid used to compute the fill and clustering ratios when ADJUST_GRID is set to 1. Number 20
MIN_GRID_SIZE Lower limit (in cells) of the grid size when ADJUST_GRID is set to 1 Number 10
MAX_GRID_SIZE Upper limit (in cells) of the grid size when ADJUST_GRID is set to 1 Number 500
ADD_LABELS Add label contour lines with the value of their level. true or false false
LABELS_FONT_SIZE Size of the font to use for labels. Number between 4 and 48 12
LABELS_FONT_FAMILY Name of the font to use for labels. The font must be on the system. Any font codes available on all database servers Sans
LABELS_SEARCH_WINDOW When ADD_LABELS is set to true, a search window is used to rate the local quality of each isoline. Smooth, continuous, long stretches with relatively flat angles are favored. This setting is multiplied by the font size to set the final window size. Number between 1 and 8 4
LABELS_INTRALEVEL_SEPARATION When ADD_LABELS is set to true, labels are automatically separated to avoid overlap. This setting specifies the distance to use when separating labels of different values (in multiples of the font size). Number between 1 and 8 4
LABELS_INTERLEVEL_SEPARATION When ADD_LABELS is set to true, more than one label can placed on the same isoline. This setting specifies the distance to use when separating labels of the same value (in percent of the total window size). Number between 0 and 50 25
LABELS_MAX_ANGLE Maximum angle, in degrees, from the vertical to use when displaying labels. Number between 0 and 90 60

To be able to construct a contour plot, we first need to grid the data in a regularly-spaced XY array. This is achieved using the GRIDDING_METHOD parameter, which is the most influential parameter of the contour plot. The GRIDDING_METHOD determines how the data is interpolated/extrapolated and will also impact the speed at which the plot can be generated. The only method supported at this time is INV_DST_POW (Inverse Distance to a Power).

The SEARCH_RADIUS heavily influences both the quality and speed of the contour plot. It is method dependent and should be adjusted based on the quantity and quality of the input data.

Once the grid is obtained, a marching squares algorithm is used to obtain the isolines. The grid can be visualized by setting RENDER_OUTPUT_GRID to 1 (true).

Additionally, we can set ADJUST_GRID to 1 (true) if the density of the data in the current viewport is so low that the resulting grid is not filled properly when using the user-specified grid size and search radius. This option will automatically adapt the grid size and/or search radius to get a better interpolation of the data by first running a coarse gridding pass, then collecting data about density and sparsity, and finally choosing the latter value accordingly before re-running the contour lines generation.

Finally, labels can be added to the isolines by setting ADD_LABELS to true. Label font size, font family, angle, and separation are the main parameters to control how the labels are displayed.

For example, to generate a contour plot image from a table with the following characteristics:

Note

The contour plot image for this example is generated from an aggregate groupby result table contour_source. This result table aggregates dropoff points and counts of points from the nyctaxi table.

curl -sS -X POST --header "Content-Type: application/json" \
--user ${USERNAME}:${PASSWORD} \
--data '{"table_name":"nyctaxi", "column_names":["dropoff_longitude","dropoff_latitude","float(count(*)) as dropoff_point_count"], "offset":0, "limit":-9999, "encoding":"json", "options":{"result_table":"contour_source"}}' \
http://${HOSTNAME}:9191/aggregate/groupby
  • SRS is PLATE_CARREE
  • Bounding box longitude is from -74.1 to -73.9 and latitude is from 40.6 to 40.9
  • Image size is 512 x 512
  • X-axis position is extracted from the contour_source table's dropoff_longitude column
  • Y-axis position is extracted from the contour_source table's dropoff_latitude column
  • Number of individually-separated isolines is set to 150
  • Number of isolines is automatically adjusted based on the viewport
  • Z value for the contour plot isolines is extracted from the contour_source table's dropoff_point_count column
  • Search radius for the isolines is 15% of the grid
  • Grid size is manually set to 50
  • Labels are added; labels of different values are separated by a space worth 5 times the font size (default font size is 12)
http://${HOSTNAME}:9191/wms?REQUEST=GetMap
&SRS=PLATE_CARREE
&LAYERS=contour_source
&BBOX=-74.1,40.6,-73.9,40.9
&WIDTH=512
&HEIGHT=512
&STYLES=contour
&FORMAT=image/png
&X_ATTR=dropoff_longitude
&Y_ATTR=dropoff_latitude
&COLORMAP=jet
&NUM_LEVELS=150
&ADJUST_LEVEL=1
&VAL_ATTR=dropoff_point_count
&SEARCH_RADIUS=15
&GRIDDING_METHOD=INV_DST_POW
&GRID_SIZE=50
&ADD_LABELS=1
&LABELS_INTRALEVEL_SEPARATION=5

LABELS

The labels mode is used to show labels on the map rather than points. Available parameters are:

Name Description Allowable Values Default Value
LABEL_LAYER name of table to render (Required)    
LABEL_X_ATTR name of column containing label's position on the x-axis Numeric column from LABEL_LAYER source table list; must be of int, double, float, or long column type Column x
LABEL_Y_ATTR name of column containing label's position on the y-axis Numeric column from LABEL_LAYER source table list; must be of int, double, float, or long column type Column y
LABEL_TEXT_STRING text of label to render All printable characters no text
LABEL_FONT font in the format of Name Style(s) Size (e.g. Arial Bold 8) Any font codes available on all database servers default server font
LABEL_TEXT_COLOR text color Hex color (with or without alpha values) or -1 (full transparency) FF000000
LABEL_TEXT_SCALE text scaling factor Number 1
LABEL_TEXT_ANGLE number of degrees clockwise to rotate the label Number 0
LABEL_DRAW_BOX draw a box around the label 0 (false) or 1 (true) 0
LABEL_DRAW_LEADER draw a leader line from each label to its x,y point specified by LABEL_LEADER_X_ATTR & LABEL_LEADER_Y_ATTR columns 0 (false) or 1 (true) 0
LABEL_LINE_WIDTH width of line for box & leader line Number 1
LABEL_LINE_COLOR color of line for box & leader line Hex color (with or without alpha values) or -1 (full transparency) FF000000
LABEL_FILL_COLOR color of fill for box Hex color (with or without alpha values) or -1 (full transparency) FF000000
LABEL_LEADER_X_ATTR name of column containing leader line's terminating position on the x-axis (the end opposite the label) Numeric column from LABEL_LAYER source table list; must be of int, double, float, or long column type N/A
LABEL_LEADER_Y_ATTR name of column containing leader line's terminating position on the y-axis (the end opposite the label) Numeric column from LABEL_LAYER source table list; must be of int, double, float, or long column type N/A
LABEL_FILTER boolean expression used to filter which labels are included from LABEL_LAYER   N/A
LABEL_X_OFFSET horizontally offset the label rendering from the actual coordinate using the given value Number N/A
LABEL_Y_OFFSET vertically offset the label rendering from the actual coordinate using the given value Number N/A

Important

When using the labels mode, LABEL_LAYER is required.

All LABELS parameters can use expressions. To read more about the different types of expressions, see expressions. Strings inside expressions must be enclosed in single or double quotes. Expressions inside the LABEL_TEXT_COLOR, LABEL_LINE_COLOR, and LABEL_FILL_COLOR parameters must resolve to 6 or 8 hex digits or the color won't work. Note that if the expression resolves to 6 hex digits, an alpha value of FF is automatically added.

To use labels, the requested TrueType fonts must be loaded on all servers in the Kinetica cluster, in the /usr/share/fonts directory. Kinetica must be restarted to see any new fonts placed in this directory.

Labels and shapes cannot be rendered in the same WMS call. Both can be shown on the same map by creating separate map layers, each with its own WMS call. When making the WMS call for the labels to be generated, the LAYERS parameter (geospatial source table containing the shapes) can be left blank.

LABEL_DRAW_BOX and LABEL_DRAW_LEADER will only take values that are castable to boolean values (e.g., 1 and 0). "TRUE" and "FALSE" are not valid.

All colors must be provided in hex notation in the format RRGGBB or AARRGGBB (to specify the alpha value). For example, partially transparent red may be given as B3FF0000.

Parameters other than the following can be either literals of the appropriate parameter type or column names containing values of the appropriate type:

  • LABEL_LAYER
  • LABEL_X_ATTR
  • LABEL_Y_ATTR
  • LABEL_LEADER_X_ATTR
  • LABEL_LEADER_Y_ATTR

For example, to generate a label image overlay from a table nyctaxi with the following characteristics:

  • SRS is EPSG:4326
  • Bounding box longitude is from -74.1 to -73.9 and latitude is from 40.6 to 40.9
  • Image size is 512 x 512
  • X-axis position is extracted from the nyctaxi table's dropoff_longitude column
  • Y-axis position is extracted from the nyctaxi table's dropoff_latitude column
  • Label text is dropoff, is white (FFFFFF), scaled to 40% smaller (0.6 x) than normal, rotated 15 degrees clockwise
  • A blue-filled (B3006BBB) box is drawn around each label
  • Labels are only drawn for dropoff points where the passenger count was greater than 5
http://${HOSTNAME}:9191/wms?REQUEST=GetMap
&SRS=EPSG:4326
&BBOX=-74.1,40.6,-73.9,40.9
&WIDTH=512
&HEIGHT=512
&STYLES=labels
&LABEL_LAYER=nyctaxi
&LABEL_X_ATTR=dropoff_longitude
&LABEL_Y_ATTR=dropoff_latitude
&LABEL_TEXT_STRING='dropoff'
&LABEL_TEXT_SCALE=0.6
&LABEL_TEXT_ANGLE=15
&LABEL_DRAW_BOX=1
&LABEL_FILL_COLOR=B3006BBB
&LABEL_FILTER=passenger_count>5
&LABEL_TEXT_COLOR=FFFFFF

ISOCHRONES

The isochrones mode is used to generate an image containing isolines for travel results using an existing graph. Isolines represent curves of equal cost, with cost typically referring to the time or distance assigned as the weights of the underlying graph.

Available parameters are:

Name Description Allowable Values Default Value
ADD_LABELS Add labels to isolines with the value of their level. true or false false
BG_COLOR Background color of the generated image. Hex notation in the format RRGGBB or AARRGGBB (to specify the alpha value) 00000000 (transparent)
COLOR Isoline color to be used when flooded contours are enabled; otherwise, isolines will follow the colormap. Hex notation in the format RRGGBB or AARRGGBB, in which case the alpha value is used for the transparency of the flooded contours. The line itself is always opaque. FF000000
COLORMAP Colormap for the isochrones
  • Perceptually-Uniform - viridis, inferno, plasma, magma
  • Sequential I - Blues, BuGn, BuPu, GnBu, Greens, Greys, Oranges, OrRd, PuBu, PuBuGn, PuRd, Purples, RdPu, Reds, YlGn, YlGnBu, YlOrBr, YlOrRd
  • Sequential II - afmhot, autumn, bone, cool, copper, gist_heat, gray, gist_gray, gist_yarg, binary, hot, pink, spring, summer, winter
  • Diverging - BrBG, bwr, coolwarm, PiYG, PRGn, PuOr, RdBu, RdGy, RdYlBu, RdYlGn, Spectral, seismic
  • Qualitative - Accent, Dark2, Paired, Pastel1, Pastel2, Set1, Set2, Set3
  • Misc - gist_earth, terrain, ocean, gist_stern, brg, CMRmap, cubehelix, gnuplot, gnuplot2, gist_ncar, spectral, nipy_spectral, jet, rainbow, gist_rainbow, hsv, flag, prism
 jet
COLOR_ISOLINES Color each isoline according to the colormap; otherwise, use the foreground color. true or false true
CONCAVITY_LEVEL Factor to qualify the concavity of the isochrone curves. The lower the value, the more convex (with 0 being completely convex and 1 being the most concave). Values (inclusive) between 0 and 1 0.5
DATA_MAX_X Upper bound for the x values. If not provided, it will be computed from the bounds of the input data. Number  
DATA_MAX_Y Upper bound for the y values. If not provided, it will be computed from the bounds of the input data. Number  
DATA_MIN_X Lower bound for the x values. If not provided, it will be computed from the bounds of the input data. Number  
DATA_MIN_Y Lower bound for the y values. If not provided, it will be computed from the bounds of the input data. Number  
GENERATE_IMAGE Generates a PNG image of the isochrones in the response. true or false true
GRAPH_NAME Name of the graph on which the isochrone is to be computed. A valid graph name  
GRID_SIZE When interpolating the graph solution to generate the isochrone, GRID_SIZE represents by the number of subdivisions along the x axis when building the grid (the y is computed using the aspect ratio of the output image). Positive integers 100
HEIGHT Height of the generated image (if applicable). If not provided, the aspect ratio multiplied by WIDTH is used. Number -1
IS_REPLICATED Replicate the SOLVE_TABLE. true or false true
LABELS_FONT_FAMILY When ADD_LABELS is set to true, name of the font to use for labels. The font must be on the system. Any font codes available on all database servers Sans
LABELS_FONT_SIZE When ADD_LABELS is set to true, size of the font to use for labels. Number between 4 and 48 12
LABELS_INTRALEVEL_SEPARATION When ADD_LABELS is set to true, labels are automatically separated to avoid overlap. This setting specifies the distance to use when separating labels of different values (in multiples of the font size). Number between 1 and 8 4
LABELS_INTERLEVEL_SEPARATION When ADD_LABELS is set to true, more than one label can placed on the same isoline. This setting specifies the distance to use when separating labels of the same value (in percent of the total window size). Number between 0 and 50 25
LABELS_MAX_ANGLE When ADD_LABELS is set to true, maximum angle, in degrees, from the vertical to use when displaying labels. Number between 0 and 90 60
LABELS_SEARCH_WINDOW When ADD_LABELS is set to true, a search window is used to rate the local quality of each isoline. Smooth, continuous, long stretches with relatively flat angles are favored. This setting is multiplied by the font size to set the final window size. Number between 1 and 8 4
LEVELS_TABLE Name of the table to output the isochrones, containing levels and their corresponding WKT geometry. If no value is provided, the table is not generated. A valid table name  
LINE_SIZE The width of the contour lines in pixels. Number between 0 and 20 3
MAX_SOLUTION_RADIUS Extent of the search around SOURCE_NODE. Set to -1.0 for unrestricted search. Number -1.0
NUM_LEVELS Number of equally-separated isochrones to compute. Positive integer 1
PROJECTION Spatial Reference System (i.e. EPSG code)
  • Plate Carree projection codes: PLATE_CARREE, EPSG:4326
  • Web Mercator projection codes: WEB_MERCATOR, 900913, EPSG:900913, 102100, EPSG:102100, 3857, EPSG:3857
  
REMOVE_PREVIOUS_RESTRICTIONS Ignore the restrictions applied to the graph during the creation stage and only use the restrictions specified in this request. true or false false
RESTRICTIONS Additional restrictions to apply to the nodes/edges of an existing graph. Restrictions must be specified using identifiers; identifiers are grouped as combinations. Identifiers can be used with existing column names, e.g., 'table.column AS RESTRICTIONS_EDGE_ID', expressions, e.g., 'column/2 AS RESTRICTIONS_VALUECOMPARED', or raw values, e.g., '{0, 0, 0, 1} AS RESTRICTIONS_ONOFFCOMPARED'. If using raw values in an identifier combination, the number of values specified must match across the combination. If REMOVE_PREVIOUS_RESTRICTIONS is set to true any provided restrictions will replace the existing restrictions. If REMOVE_PREVIOUS_RESTRICTIONS is set to false, any provided restrictions will be added (in the case of 'RESTRICTIONS_VALUECOMPARED') to or replaced (in the case of 'RESTRICTIONS_ONOFFCOMPARED') Valid restrictions  
RESTRICTION_THRESHOLD_VALUE Value-based restriction comparison. Any node or edge with a 'RESTRICTIONS_VALUECOMPARED' value greater than their RESTRICTION_THRESHOLD_VALUE will not be included in the solution.    
SEARCH_RADIUS When interpolating the graph solution to generate the isochrone, the SEARCH_RADIUS is the neighborhood of influence of sample data (in percent of the image/grid). Positive integer 20
SOLVE_DIRECTION Specify the direction of the isochrones solution: either toward the SOURCE_NODE or leading away from it. from_source or to_source  
SOLVE_TABLE Name of the table to host intermediate solve results containing the position and cost for each vertex in the underlying graph. A valid table name ""
SOURCE_NODE Starting vertex on the underlying graph from/to which the isochrones are created.    
TEXT_COLOR When ADD_LABELS is set to true, color for the labels. Hex notation in the format RRGGBB or AARRGGBB (to specify the alpha values) or -1 (full transparency) FF000000
UNIFORM_WEIGHTS When specified, assigns the given value to all the edges in the graph. Note that weights provided in WEIGHTS_ON_EDGES will override this value.    
WEIGHTS_ON_EDGES Additional weights to apply to the edges of an existing graph. Weights must be specified using identifiers; identifiers are grouped as combinations. Identifiers can be used with existing column names, e.g., 'table.column AS WEIGHTS_EDGE_ID', expressions, e.g., 'ST_LENGTH(wkt) AS WEIGHTS_VALUESPECIFIED', or raw values, e.g., '{4, 15, 2} AS WEIGHTS_VALUESPECIFIED'. Any provided weights will be added (in the case of 'WEIGHTS_VALUESPECIFIED') to or multiplied with (in the case of 'WEIGHTS_FACTORSPECIFIED') the existing weight(s). If using raw values in an identifier combination, the number of values specified must match across the combination. Valid weights  
WIDTH Width of the generated image (if applicable). Positive integer 512
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