Package 'googletraffic' reference manual

Title:	Google Traffic
Description:	Create geographically referenced traffic data from the Google Maps JavaScript API <https://developers.google.com/maps/documentation/javascript/examples/layer-traffic>.
Authors:	Robert Marty [aut, cre]
Maintainer:	Robert Marty <[email protected]>
License:	MIT + file LICENSE
Version:	0.1.7
Built:	2024-11-14 05:30:45 UTC
Source:	https://github.com/dime-worldbank/googletraffic

Converts PNG to raster

Description

Converts PNG of Google traffic data to raster and translates color values to traffic values

Usage

gt_load_png_as_traffic_raster(
  filename,
  location,
  height,
  width,
  zoom,
  traffic_color_dist_thresh = 4.6,
  traffic_color_dist_metric = "CIEDE2000"
)
gt_load_png_as_traffic_raster(
  filename,
  location,
  height,
  width,
  zoom,
  traffic_color_dist_thresh = 4.6,
  traffic_color_dist_metric = "CIEDE2000"
)

Arguments

`filename`	Filename of PNG file
`location`	Vector of latitude and longitude used to create PNG file using `gt_make_png()`
`height`	Height (in pixels; pixel length depends on zoom) used to create PNG file using `gt_make_png()`
`width`	Width (in pixels; pixel length depends on zoom) used to create PNG file using `gt_make_png()`
`zoom`	Zoom level used to create PNG file using `gt_make_png()`
`traffic_color_dist_thresh`	Google traffic relies on four main base colors: `⁠#63D668⁠` for no traffic, `⁠#FF974D⁠` for medium traffic, `⁠#F23C32⁠` for high traffic, and `⁠#811F1F⁠` for heavy traffic. Slight variations of these colors can also represent traffic. By default, the base colors and all colors within a 4.6 color distance of each base color are used to define traffic; by default, the `CIEDE2000` metric is used to determine color distance. A value of 2.3 is one threshold used to define a "just noticeable distance" (JND) between colors (by default, 2 X JND is used). This parameter changes the color distance from the base colors used to define colors as traffic. For more information, see here.
`traffic_color_dist_metric`	See above; this parameter changes the metric used to calculate distances between colors. By default, `CIEDE2000` is used; `CIE76` and `CIE94` can also be used. For more information, see here.

Value

Returns a raster where each pixel represents traffic level (1 = no traffic, 2 = medium traffic, 3 = traffic delays, 4 = heavy traffic)

References

Markus Hilpert, Jenni A. Shearston, Jemaleddin Cole, Steven N. Chillrud, and Micaela E. Martinez. Acquisition and analysis of crowd-sourced traffic data. CoRR, abs/2105.12235, 2021.

Pavel Pokorny. Determining traffic levels in cities using google maps. In 2017 Fourth International Conference on Mathematics and Computers in Sciences and in Industry (MCSI), pages 144–147, 2017.

Examples

## Not run: 
## Make png
gt_make_png(location     = c(40.712778, -74.006111),
            height       = 1000,
            width        = 1000,
            zoom         = 16,
            out_filename = "google_traffic.png",
            google_key   = "GOOGLE-KEY-HERE")

## Load png as traffic raster
r <- gt_load_png_as_traffic_raster(filename = "google_traffic.png",
                                   location = c(40.712778, -74.006111),
                                   height   = 1000,
                                   width    = 1000,
                                   zoom     = 16)

## End(Not run)                                    

## Not run: 
## Make png
gt_make_png(location     = c(40.712778, -74.006111),
            height       = 1000,
            width        = 1000,
            zoom         = 16,
            out_filename = "google_traffic.png",
            google_key   = "GOOGLE-KEY-HERE")

## Load png as traffic raster
r <- gt_load_png_as_traffic_raster(filename = "google_traffic.png",
                                   location = c(40.712778, -74.006111),
                                   height   = 1000,
                                   width    = 1000,
                                   zoom     = 16)

## End(Not run)

Creates Grid to Query Google Traffic

Description

Creates a grid of sf polygons, where traffic data for each polygon can then be queried using gt_make_raster_from_grid().

Usage

gt_make_grid(
  polygon,
  zoom,
  height_width_max = 2000,
  height = NULL,
  width = NULL,
  reduce_hw = 10
)
gt_make_grid(
  polygon,
  zoom,
  height_width_max = 2000,
  height = NULL,
  width = NULL,
  reduce_hw = 10
)

Arguments

`polygon`	Polygon (`sf` object or `SpatialPolygonsDataframe`) in WGS84 CRS the defines region to be queried.
`zoom`	Zoom level; integer from 5 to 20. For more information about how zoom levels correspond to pixel size, see here and here.
`height_width_max`	Maximum pixel height and width to check using for each grid (pixel length depends on zoom). If the same number of grids can be made with a smaller height/width, the function will use a smaller height/width. If `height` and `width` are specified, that height and width will be used and `height_width_max` will be ignored. (Default: `2000`)
`height`	Height, in pixels, for each grid (pixel length depends on zoom). Enter a `height` to manually specify the height; otherwise, a height of `height_width_max` or smaller will be used.
`width`	Pixel, in pixels, for each grid (pixel length depends on zoom). Enter a `width` to manually specify the width; otherwise, a width of `height_width_max` or smaller will be used.
`reduce_hw`	Number of pixels to reduce height/width by. Doing so creates some overlap between grids to ensure there is not blank space between grids. (Default: 10).

Value

Returns an sf dataframe with the locations to query, including parameters needed for gt_make_raster_from_grid()

Examples

## Make polygon
poly_sf <- c(xmin = -74.02426,
             xmax = -73.91048,
             ymin = 40.70042,
             ymax = 40.87858) |>
  sf::st_bbox() |>
  sf::st_as_sfc() |>
  sf::st_as_sf()

sf::st_crs(poly_sf) <- 4326

## Make grid using polygon
grid_sf <- gt_make_grid(polygon = poly_sf,
                        height  = 2000,
                        width   = 2000,
                        zoom    = 16)

## Make polygon
poly_sf <- c(xmin = -74.02426,
             xmax = -73.91048,
             ymin = 40.70042,
             ymax = 40.87858) |>
  sf::st_bbox() |>
  sf::st_as_sfc() |>
  sf::st_as_sf()

sf::st_crs(poly_sf) <- 4326

## Make grid using polygon
grid_sf <- gt_make_grid(polygon = poly_sf,
                        height  = 2000,
                        width   = 2000,
                        zoom    = 16)

Make Google Traffic PNG

Description

Make a png file of Google traffic data. The gt_load_png_as_traffic_raster() function can then be used to convert the png into a traffic raster

Usage

gt_make_png(
  location,
  height,
  width,
  zoom,
  out_filename,
  google_key,
  webshot_zoom = 1,
  webshot_delay = NULL,
  print_progress = TRUE
)
gt_make_png(
  location,
  height,
  width,
  zoom,
  out_filename,
  google_key,
  webshot_zoom = 1,
  webshot_delay = NULL,
  print_progress = TRUE
)

Arguments

`location`	Vector of latitude and longitude
`height`	Height (in pixels; pixel length depends on zoom)
`width`	Width (in pixels; pixel length depends on zoom)
`zoom`	Zoom level; integer from 5 to 20. For more information about how zoom levels correspond to pixel size, see here and here.
`out_filename`	Filename of PNG file to make
`google_key`	Google API key, where the Maps JavaScript API is enabled. To create a Google API key, follow these instructions.
`webshot_zoom`	How many pixels should be created relative to height and width values. If `height` and `width` are set to `100` and `webshot_zoom` is set to `2`, the resulting raster will have dimensions of about `⁠200x200⁠` (default: `1`).
`webshot_delay`	How long to wait for Google traffic layer to render. Larger height/widths require longer delay times. If `NULL`, the following delay time (in seconds) is used: `delay = max(height,width)/200`.
`print_progress`	Whether to print function progress (default: `TRUE`)

Value

Returns a PNG file showing traffic levels.

References

Markus Hilpert, Jenni A. Shearston, Jemaleddin Cole, Steven N. Chillrud, and Micaela E. Martinez. Acquisition and analysis of crowd-sourced traffic data. CoRR, abs/2105.12235, 2021.

Pavel Pokorny. Determining traffic levels in cities using google maps. In 2017 Fourth International Conference on Mathematics and Computers in Sciences and in Industry (MCSI), pages 144–147, 2017.

Examples

## Not run: 
gt_make_png(location     = c(40.712778, -74.006111),
            height       = 1000,
            width        = 1000,
            zoom         = 16,
            out_filename = "google_traffic.png",
            google_key   = "GOOGLE-KEY-HERE")

## End(Not run)

## Not run: 
gt_make_png(location     = c(40.712778, -74.006111),
            height       = 1000,
            width        = 1000,
            zoom         = 16,
            out_filename = "google_traffic.png",
            google_key   = "GOOGLE-KEY-HERE")

## End(Not run)

Make Google Traffic Raster

Description

Make a raster of Google traffic data, where each pixel has one of four values indicating traffic volume (no traffic, light, moderate, and heavy).

Usage

gt_make_raster(
  location,
  height,
  width,
  zoom,
  google_key,
  traffic_color_dist_thresh = 4.6,
  traffic_color_dist_metric = "CIEDE2000",
  webshot_zoom = 1,
  webshot_delay = NULL,
  print_progress = TRUE
)
gt_make_raster(
  location,
  height,
  width,
  zoom,
  google_key,
  traffic_color_dist_thresh = 4.6,
  traffic_color_dist_metric = "CIEDE2000",
  webshot_zoom = 1,
  webshot_delay = NULL,
  print_progress = TRUE
)

Arguments

`location`	Vector of latitude and longitude
`height`	Height (in pixels; pixel length depends on zoom)
`width`	Width (in pixels; pixel length depends on zoom)
`zoom`	Zoom level; integer from 5 to 20. For more information about how zoom levels correspond to pixel size, see here and here.
`google_key`	Google API key, where the Maps JavaScript API is enabled. To create a Google API key, follow these instructions.
`traffic_color_dist_thresh`	Google traffic relies on four main base colors: `⁠#63D668⁠` for no traffic, `⁠#FF974D⁠` for medium traffic, `⁠#F23C32⁠` for high traffic, and `⁠#811F1F⁠` for heavy traffic. Slight variations of these colors can also represent traffic. By default, the base colors and all colors within a 4.6 color distance of each base color are used to define traffic; by default, the `CIEDE2000` metric is used to determine color distance. A value of 2.3 is one threshold used to define a "just noticeable distance" (JND) between colors (by default, 2 X JND is used). This parameter changes the color distance from the base colors used to define colors as traffic. For more information, see here.
`traffic_color_dist_metric`	See above; this parameter changes the metric used to calculate distances between colors. By default, `CIEDE2000` is used; `CIE76` and `CIE94` can also be used. For more information, see here.
`webshot_zoom`	How many pixels should be created relative to height and width values. If `height` and `width` are set to `100` and `webshot_zoom` is set to `2`, the resulting raster will have dimensions of about `⁠200x200⁠` (default: `1`).
`webshot_delay`	How long to wait for Google traffic layer to render. Larger height/widths require longer delay times. If `NULL`, the following delay time (in seconds) is used: `delay = max(height,width)/200`.
`print_progress`	Whether to print function progress (default: `TRUE`)

Value

Returns a georeferenced raster. Raster pixels can contain the following values: 1 = no traffic; 2 = medium traffic; 3 = high traffic; 4 = heavy traffic.

References

Markus Hilpert, Jenni A. Shearston, Jemaleddin Cole, Steven N. Chillrud, and Micaela E. Martinez. Acquisition and analysis of crowd-sourced traffic data. CoRR, abs/2105.12235, 2021.

Pavel Pokorny. Determining traffic levels in cities using google maps. In 2017 Fourth International Conference on Mathematics and Computers in Sciences and in Industry (MCSI), pages 144–147, 2017.

Examples

## Not run: 
r <- gt_make_raster(location   = c(40.712778, -74.006111),
                    height     = 1000,
                    width      = 1000,
                    zoom       = 16,
                    google_key = "GOOGLE-KEY-HERE")

## End(Not run)

## Not run: 
r <- gt_make_raster(location   = c(40.712778, -74.006111),
                    height     = 1000,
                    width      = 1000,
                    zoom       = 16,
                    google_key = "GOOGLE-KEY-HERE")

## End(Not run)

Make Google Traffic Raster Based on Grid of Coordinates

Description

Make a raster of Google traffic data, where each pixel has one of four values indicating traffic volume (no traffic, light, moderate, and heavy).

Usage

gt_make_raster_from_grid(
  grid_param_df,
  google_key,
  traffic_color_dist_thresh = 4.6,
  traffic_color_dist_metric = "CIEDE2000",
  webshot_zoom = 1,
  webshot_delay = NULL,
  return_list_of_rasters = FALSE,
  print_progress = TRUE
)
gt_make_raster_from_grid(
  grid_param_df,
  google_key,
  traffic_color_dist_thresh = 4.6,
  traffic_color_dist_metric = "CIEDE2000",
  webshot_zoom = 1,
  webshot_delay = NULL,
  return_list_of_rasters = FALSE,
  print_progress = TRUE
)

Arguments

`grid_param_df`	Grid parameter dataframe produced from `gt_make_grid()`
`google_key`	Google API key, where the Maps JavaScript API is enabled. To create a Google API key, follow these instructions.
`traffic_color_dist_thresh`	Google traffic relies on four main base colors: `⁠#63D668⁠` for no traffic, `⁠#FF974D⁠` for medium traffic, `⁠#F23C32⁠` for high traffic, and `⁠#811F1F⁠` for heavy traffic. Slight variations of these colors can also represent traffic. By default, the base colors and all colors within a 4.6 color distance of each base color are used to define traffic; by default, the `CIEDE2000` metric is used to determine color distance. A value of 2.3 is one threshold used to define a "just noticeable distance" (JND) between colors (by default, 2 X JND is used). This parameter changes the color distance from the base colors used to define colors as traffic. For more information, see here.
`traffic_color_dist_metric`	See above; this parameter changes the metric used to calculate distances between colors. By default, `CIEDE2000` is used; `CIE76` and `CIE94` can also be used. For more information, see here.
`webshot_zoom`	How many pixels should be created relative to height and width values. If `height` and `width` are set to `100` and `webshot_zoom` is set to `2`, the resulting raster will have dimensions of about `⁠200x200⁠` (default: `1`).
`webshot_delay`	How long to wait for Google traffic layer to render. Larger height/widths require longer delay times. If `NULL`, the following delay time (in seconds) is used: `delay = max(height,width)/200`.
`return_list_of_rasters`	Instead of merging traffic rasters produced for each grid together into one large raster, return a list of rasters (default: `FALSE`)
`print_progress`	Whether to print function progress (default: `TRUE`)

Value

Returns a georeferenced raster. Raster pixels can contain the following values: 1 = no traffic; 2 = medium traffic; 3 = high traffic; 4 = heavy traffic.

References

Markus Hilpert, Jenni A. Shearston, Jemaleddin Cole, Steven N. Chillrud, and Micaela E. Martinez. Acquisition and analysis of crowd-sourced traffic data. CoRR, abs/2105.12235, 2021.

Pavel Pokorny. Determining traffic levels in cities using google maps. In 2017 Fourth International Conference on Mathematics and Computers in Sciences and in Industry (MCSI), pages 144–147, 2017.

Examples

## Not run: 
## Grab polygon of Manhattan
us_sp <- raster::getData('GADM', country='USA', level=2)
ny_sp <- us_sp[us_sp$NAME_2 %in% "New York",]

## Make Grid
grid_df <- gt_make_grid(polygon = ny_sp,
                       height   = 2000,
                       width    = 2000,
                       zoom     = 16)

## Make raster from grid                        
r <- gt_make_raster_from_grid(grid_param_df = grid_clean_df,
                              google_key    = "GOOGLE-KEY-HERE")

## End(Not run)

## Not run: 
## Grab polygon of Manhattan
us_sp <- raster::getData('GADM', country='USA', level=2)
ny_sp <- us_sp[us_sp$NAME_2 %in% "New York",]

## Make Grid
grid_df <- gt_make_grid(polygon = ny_sp,
                       height   = 2000,
                       width    = 2000,
                       zoom     = 16)

## Make raster from grid                        
r <- gt_make_raster_from_grid(grid_param_df = grid_clean_df,
                              google_key    = "GOOGLE-KEY-HERE")

## End(Not run)

Make Google Traffic Raster Based on Polygon

Description

Make a raster of Google traffic data, where each pixel has one of four values indicating traffic volume (no traffic, light, moderate, and heavy).

Usage

gt_make_raster_from_polygon(
  polygon,
  zoom,
  google_key,
  height_width_max = 2000,
  height = NULL,
  width = NULL,
  traffic_color_dist_thresh = 4.6,
  traffic_color_dist_metric = "CIEDE2000",
  webshot_zoom = 1,
  webshot_delay = NULL,
  reduce_hw = 10,
  return_list_of_rasters = FALSE,
  mask_to_polygon = TRUE,
  print_progress = TRUE
)
gt_make_raster_from_polygon(
  polygon,
  zoom,
  google_key,
  height_width_max = 2000,
  height = NULL,
  width = NULL,
  traffic_color_dist_thresh = 4.6,
  traffic_color_dist_metric = "CIEDE2000",
  webshot_zoom = 1,
  webshot_delay = NULL,
  reduce_hw = 10,
  return_list_of_rasters = FALSE,
  mask_to_polygon = TRUE,
  print_progress = TRUE
)

Arguments

`polygon`	Polygon (`sf` object or `SpatialPolygonsDataframe`) in WGS84 CRS
`zoom`	Zoom level; integer from 5 to 20. For more information about how zoom levels correspond to pixel size, see here and here.
`google_key`	Google API key, where the Maps JavaScript API is enabled. To create a Google API key, follow these instructions.
`height_width_max`	Maximum pixel height and width to check using for each API query (pixel length depends on zoom). If the same number of API queries can be made with a smaller height/width, the function will use a smaller height/width. If `height` and `width` are specified, that height and width will be used and `height_width_max` will be ignored. (Default: `2000`)
`height`	Height, in pixels, for each API query (pixel length depends on zoom). Enter a `height` to manually specify the height; otherwise, a height of `height_width_max` or smaller will be used.
`width`	Pixel, in pixels, for each API query (pixel length depends on zoom). Enter a `width` to manually specify the width; otherwise, a width of `height_width_max` or smaller will be used.
`traffic_color_dist_thresh`	Google traffic relies on four main base colors: `⁠#63D668⁠` for no traffic, `⁠#FF974D⁠` for medium traffic, `⁠#F23C32⁠` for high traffic, and `⁠#811F1F⁠` for heavy traffic. Slight variations of these colors can also represent traffic. By default, the base colors and all colors within a 4.6 color distance of each base color are used to define traffic; by default, the `CIEDE2000` metric is used to determine color distance. A value of 2.3 is one threshold used to define a "just noticeable distance" (JND) between colors (by default, 2 X JND is used). This parameter changes the color distance from the base colors used to define colors as traffic. For more information, see here.
`traffic_color_dist_metric`	See above; this parameter changes the metric used to calculate distances between colors. By default, `CIEDE2000` is used; `CIE76` and `CIE94` can also be used. For more information, see here.
`webshot_zoom`	How many pixels should be created relative to height and width values. If `height` and `width` are set to `100` and `webshot_zoom` is set to `2`, the resulting raster will have dimensions of about `⁠200x200⁠` (default: `1`).
`webshot_delay`	How long to wait for Google traffic layer to render (in seconds). Larger height/widths require longer delay times. If `NULL`, the following delay time (in seconds) is used: `delay = max(height,width)/200`.
`reduce_hw`	Number of pixels to reduce height/width by. Doing so creates some overlap between grids to ensure there is not blank space between tiles. (Default: `10`).
`return_list_of_rasters`	Whether to return a list of raster tiles instead of mosaicing together. (Default: `FALSE`).
`mask_to_polygon`	Whether to mask raster to `polygon`. (Default: `TRUE`).
`print_progress`	Show progress for which grid / API query has been processed. (Default: `TRUE`).

Value

Returns a georeferenced raster. Raster pixels can contain the following values: 1 = no traffic; 2 = medium traffic; 3 = high traffic; 4 = heavy traffic.

References

Markus Hilpert, Jenni A. Shearston, Jemaleddin Cole, Steven N. Chillrud, and Micaela E. Martinez. Acquisition and analysis of crowd-sourced traffic data. CoRR, abs/2105.12235, 2021.

Pavel Pokorny. Determining traffic levels in cities using google maps. In 2017 Fourth International Conference on Mathematics and Computers in Sciences and in Industry (MCSI), pages 144–147, 2017.

Examples

## Not run: 
## Grab polygon of Manhattan
us_sp <- raster::getData('GADM', country='USA', level=2)
ny_sp <- us_sp[us_sp$NAME_2 %in% "New York",]

## Make raster
r <- gt_make_raster_from_polygon(polygon    = ny_sp,
                                 height     = 2000,
                                 width      = 2000,
                                 zoom       = 16,
                                 google_key = "GOOGLE-KEY-HERE")

## End(Not run) 

## Not run: 
## Grab polygon of Manhattan
us_sp <- raster::getData('GADM', country='USA', level=2)
ny_sp <- us_sp[us_sp$NAME_2 %in% "New York",]

## Make raster
r <- gt_make_raster_from_polygon(polygon    = ny_sp,
                                 height     = 2000,
                                 width      = 2000,
                                 zoom       = 16,
                                 google_key = "GOOGLE-KEY-HERE")

## End(Not run)

Mosaic rasters with different origins and resolutions

Description

The raster::mosaic() function requires rasters to have the same origin and resolution. However, when producing multiple rasters to query traffic data across a large study area, the rasters will not have the same origins and may not have the same resolutions (in cases where rasters at different latitudes are queried). gt_mosaic() allows for mosaicing rasters with different origins and resolutions.

Usage

gt_mosaic(r_list)
gt_mosaic(r_list)

Arguments

r_list

List of rasters

Value

Returns a raster.

Examples

r1 <- raster::raster(ncol=10, nrow=10, xmn = -10, xmx = 1,  ymn = -10, ymx = 1)
r2 <- raster::raster(ncol=10, nrow=10, xmn = 0,   xmx = 10, ymn = 0,   ymx = 10)
r3 <- raster::raster(ncol=10, nrow=10, xmn = 9,   xmx = 20, ymn = 9,   ymx = 20)

r123 <- list(r1, r2, r3)

r <- gt_mosaic(r123)

r1 <- raster::raster(ncol=10, nrow=10, xmn = -10, xmx = 1,  ymn = -10, ymx = 1)
r2 <- raster::raster(ncol=10, nrow=10, xmn = 0,   xmx = 10, ymn = 0,   ymx = 10)
r3 <- raster::raster(ncol=10, nrow=10, xmn = 9,   xmx = 20, ymn = 9,   ymx = 20)

r123 <- list(r1, r2, r3)

r <- gt_mosaic(r123)

Package 'googletraffic'

Help Index

Converts PNG to raster

Description

Usage

Arguments

Value

References

Examples

Creates Grid to Query Google Traffic

Description

Usage

Arguments

Value

Examples

Make Google Traffic PNG

Description

Usage

Arguments

Value

References

Examples

Make Google Traffic Raster

Description

Usage

Arguments

Value

References

Examples

Make Google Traffic Raster Based on Grid of Coordinates

Description

Usage

Arguments

Value

References

Examples

Make Google Traffic Raster Based on Polygon

Description

Usage

Arguments

Value

References

Examples

Mosaic rasters with different origins and resolutions

Description

Usage

Arguments

Value

Examples