The Areas of a Page a Reader Measures In

Summary

A site plan drawn at one to a hundred is useless to measure in points: the reader wants metres. A map wants latitude and longitude. A viewport says which rectangle of the page is the plan or the map, and in what units a reader's measuring tool reads inside it; outside every viewport it measures the page itself.

Request Schema

• page_viewports — array, optional, empty by default.
• page_viewports[].page — integer, required, counting from 1, as every page number in a request counts.
• page_viewports[].viewports — array, required. Each viewport has llx, lly, urx and ury, and optionally a name, a measure, rectilinear or geospatial, and point_data, sets of measured points, each with names, the name of each column — LAT, LON and ALT for a latitude, a longitude and an altitude, or names the customer chooses — and points, one row of numbers per point. Point data needs a geospatial measure and PDF 2.0.
• Units: each list of units — x, distance, area, and y's units beside y_in_x, what one y unit is worth in x units, with angles and slopes — holds the largest first, each unit a label and a factor, and may state fraction ({"decimals": 2}, {"fraction": 8}, "rounded" or "truncated"), exact, thousands_separator, decimal_mark, label_spacing and label_first. origin is the point measured from. A map states its system, {"geographic": {"epsg": 4326}} or {"projected": {"wkt": "…"}}, its points, each {"at": [x, y], "latitude": …, "longitude": …} or {"at": [x, y], "easting": …, "northing": …}, and may state shown_in, neatline and display_units, {"length", "area", "angle"}: metre, kilometre, foot, us_survey_foot, mile or nautical_mile; square_metre, hectare, square_kilometre, square_foot, acre or square_mile; degree or grad.

A list of no unit is refused, and so are a factor that is not a number above nought, a viewport of no width, a control point outside its viewport, and a latitude or a longitude out of range.