(lisppad draw map)

Library (lisppad draw map) provides an API for creating map snapshots. A map snapshot encapsulates a map image and provides a procedure for mapping locations to points on the image. This makes it possible to draw on top of the image based on locations (lat/longs). Here is a typical use case for this library:

(import (lispkit draw)
        (lisppad location)
        (lisppad draw map))
(define d
  (let*
    (; Determine the current location
     (center (current-location))
     ; Show a 1km box around the center
     (area   (size 1000 1000))
     ; Create a map snapshot of 500x500 points
     (snapsh (make-map-snapshot center area (size 500 500) 'satellite))
     ; Determine the points on the map image for the center
     (pt     (map-snapshot-point snapsh center)))
    ; Create a drawing of the map with highlighted center
    (drawing
      ; Draw the map at the origin of the drawing
      (draw-image (map-snapshot-image snapsh) (point 0 0))
      ; Highlight the center with a red circle
      (set-fill-color red)
      (fill-ellipse 
        (rect (point (- (point-x pt) 4) (- (point-y pt) 4))
              (size 8 8))))))

The body of the let* form first draws the image and then layers a red ellipse on top. This is done in the context of a drawing, which can then be turned into an image and saved.

(map-snapshot? obj)

Returns #t if obj is a map snapshot object; otherwise #f is returned.

(make-map-snapshot center dist size) (make-map-snapshot center dist size type) (make-map-snapshot center dist size type poi) (make-map-snapshot center dist size type poi bldng)

Creates a new map snapshot object which represents a rectangular area of a map whose center is the location center. Locations are created and managed via library (lisppad location). dist describes the width and height of the map region. If is either a lat-long-span object or a size object, as defined by library (lispkit draw). lat-long-span objects describe a width and height in terms of a north-to-south and east-to-west distance measured in degrees. size objects are interpreted as width and height measured in meters. size is a size object describing the dimensions of the image in points. type is a symbold that indicates the map type. Supported are:

• standard: Street map that shows the position of all roads and some road names.

• satellite: Satellite imagery of the area.

• satellite-flyover: Satellite image of the area with flyover data where available.

• hybrid: Satellite image of the area with road and road name information layered on top.

• hybrid-flyover: Hybrid satellite image with flyover data where available.

• standard-muted: Street map where the underlying map details are less emphasized to make custom data on top stand out more.

poi is a list of symbols indicating the categories for which point of interests are highlighted on the map. The following categories are supported:

airport, amusement-park, aquarium, atm, bakery, bank, beach, brewery, cafe, campground, car-rental, ev-charger, fire-station, fitness-center, supermarket, gas-station, hospital, hotel, laundry, library, marina movie-theater, museum, national-park, nightlife, park, parking, pharmacy, police, post-office, public-transport, restaurant, restroom, school, stadium, store, theater, university, winery, zoo.

bldng is a boolean parameter (default is #f) indicating whether to show buildings or not.

(map-snapshot-image msh)

Given a map snapshot object msh, procedure map-snapshot-image returns an image of the map encapsulated by msh.

(map-snapshot-point msh loc) (map-snapshot-point msh lat long)

Given a map snapshot object msh, procedure map-snapshot-point returns a point on the image of the map that matches the given location loc, or the location derived from the given latitude lat and longitude long.

(lat-long-span latspan longspan)

Returns a new lat-long-span object from the given latitudal (north-to-south) and longitudal (east-to-west) distances latspan and longspan measured in degrees.