Tag: projection

Back 2 School: Vector Tiles in Azimuthal? Check it…


This post comes courtesy of cartographer Jonah Adkins, from Newport News, Virginia. Jonah is a GIS alchemist, routinely crafting beautiful and insightful work, and sharing his process. … Vector tiles in Azimuthal Equal Area?? NO WAY! Way I’ve been learning … Continue reading

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Mercator’s 500th birthday

By Aileen Buckley, Mapping Center Lead


March 5, 2012 marked what would be the 500th birthday of Gerhardus Mercator (1512—1594). Mercator was a Flemish map maker and geographer. In 1569, he created the Mercator projection, which is widely used for navigation because straight lines drawn on maps that use this cylindrical projection are lines of constant compass bearing (rhumb lines); a variation of his projection is used today for many web maps. Mercator mastered the essentials of mathematics, geography, and astronomy and primarily supported himself through his craftsmanship of mathematical instruments. With Gemma Frisius, another producer of globes and mathematical instruments, and Gaspar à Myrica, an engraver and goldsmith, he made Louvain, Belgium, an important center for the construction of globes, maps, and astronomical instruments. Continue reading

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Making a large-scale 3D map: Part 1

?By Kenneth Field, Esri Research Cartographer

Making a Large Scale 3D map Part 1 thumbnail

1. Introduction

With the release of Esri CityEngine, advanced tools now exist for creating rich 3D content for urban planning, architecture, entertainment, and GIS, but does 3D allow you to build useful static maps? Can we make 3D static maps with ArcGIS and what are the design considerations?

3D views of our world are nothing new in cartography, and you don’t have to have moving, interactive, or animated interfaces to create interesting 3D maps, as useful as they are in their own right. Continue reading

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Tissot’s indicatrix helps illustrate map projection distortion

By Aileen Buckley, Mapping Center Lead

Tissot's thumbnail

Tissot’s indicatrix was first developed by French mathematician Nicolas Auguste Tissot in 1859 as a tool to characterize the distortion due to projecting a spherical representation of the earth onto a flat surface, i.e., a map projection.

This graphic tool helps you see what type of distortion occurs in the size, shape, and orientation of ellipses that would be circles were they located on the earth’s surface. When a circle is projected onto a flat surface through the map projection process, the result is an ellipse whose semi-minor and semi-major axes indicate the two principal directions (often but not always north-south and east-west) along which scale is maximal and minimal at that point on the map.

Continue reading

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Map projection animations

By Dr. A Jon Kimerling, Professor Emeritus, Oregon State University

Albers Continuum Thumb

There are many ways that we can think about similarities among map projections. We can group projections as similar in map scale or as serving similar user communities. Cartographers often take a different approach and group projections by similar geometrical properties or by similar mathematics underlying their construction. Grouping projections into cylindrical, conic, and azimuthal classes is an example of grouping by similar geometrical properties, whereas categorizing projections as conformal, equal area, and equidistant is an example of grouping by similar distortion properties that are a consequence of the mathematics underlying the projections. Continue reading

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Avoid the temptation to perform measurements in Web Mercator

03/18/10–What is the best way to measure distance and area in maps that use the Web Mercator projection? Avoid the temptation to perform measurements of polylines and polygons
in Web Mercator. You should instead re-project user-submitted geometries
into a more appropriate coordinate system before you perform a
measurement. Learn more from the ArcGIS Server blog.

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