Category: Mapping

Dot maps for US General Soil Map (STATSGO) data

By Linda Barrett, Department of Geology and Environmental Science, University of Akron

Dot Maps for STATSGO data - Thumbnail

After seeing my poster that described using dot maps to show soils at the AAG conference in Boston a few weeks ago, Charlie Frye suggested that I write this entry to describe my maps and the technique used to create them.  This seemed especially appropriate given the recent entries in this blog about dot maps. Continue reading

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Color ramps reorganized

By Jaynya Richards, Esri Research Cartographer

We recently made some changes to the color ramp styles on Mapping Center under the ArcGIS Resources tab. You will now find a single ZIP file that contains a variety of color ramps. Our purpose in reorganizing the color ramps was to make it easier to find and use the color ramps.   The way we did that was to organize all the color ramps of a particular theme into a separate style file.  Then we gave each of the style file a name that better describes the purpose of the color ramps. Continue reading

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Hypsometric tinting

By Aileen Buckley, Mapping Center Lead

Hypso Tinting - Thumb

Hypsometric tinting (also called layer tinting, elevation tinting, elevation coloring or hypsometric coloring) is used to enhance elevation zones so map readers can better see differences in relief. You can think of it as “coloring between the lines” where the lines are contours (lines of equal elevation) or isobaths (lines of equal depth below the surface of a body of water). Hypsometric tints are often laid transparently over a hillshaded surface. Continue reading

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Tips for getting better map drawing performance

By Charlie Frye, Esri Chief Cartographer

If you’re making a map that is either a large format print map or a map that will be served via ArcGIS Server, squeezing every bit of wasted time out of drawing performance is critical.  Don’t get tired of sitting there drinking extra cups of coffee watching the word “Drawing”, all your layer names, and that little blue globe. If you’re finding it stressful to explain when updates will be coming, or the timing for caching the map you are serving, or your map services generate complaints about poor performance, then try the two tips in this entry. Continue reading

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Symbolizing rivers and streams with proportional symbols

By Charlie Frye, Esri Chief Cartographer

Last week we received an interesting question on Ask a Cartographer about how to create tapered stream or river line symbols. Tapered symbols are actually a bit more complicated than what is shown to the left; those lines are proportionally scaled symbols that are based on an attribute value. Notice that each stream is a single line width.  Tapered symbols would actually change widths along the length of a given feature, giving a very smooth effect. Tapering is more useful for depicting flows that range widely in value or magnitude, whereas proportional symbols are usually an excellent solution for symbolizing rivers and streams.  Continue reading

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Dot density mapping with ArcMap: Part 2–Defining exclusions and inclusions

By Daniel Smith and Alex Quintero, University of Redlands, Masters of Science In GIS Program

Exclusions Inclusions Part 2 - Thumbnail

In the first dot density mapping blog, we discussed the workflow for creating dot density maps using ArcMap.  In that discussion we emphasized the need for using exclusion or inclusion layers.  Here is an example of how we set up the inclusion and exclusion choices for mapping population density in San Bernardino County, the county with the largest land area in the conterminous United States. Because of its size and the fact that population is not evenly distributed throughout the county (rather, it is concentrated in the southwest corner, around where Redlands is located), this county exemplifies the limitations of dot density mapping without inclusions/exclusions when mapping population density at the county, the state or even the country level. Continue reading

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Dot Density Mapping with ArcMap: Part 1

By Alex Quitero and Daniel Smith, University of Redlands, Masters of Science in GIS Program

Several weeks ago, after a colloquium given by Dr. Aileen Buckley on the devolution of cartographic theory, we approached her about research opportunities that she mentioned. She was glad to accept our help and put us in contact with Dr. A. Jon Kimerling from the Oregon State University. The research he was undertaking during his sabbatical in Redlands, CA dealt with a particular mapping method in the cartographer’s bag of tricks – dot density mapping. After discussing the research issues with Dr. Kimerling, we were tasked with developing a series of maps to supplement his research (see his presentation: “Dotting the Dot Map, Revisited” and to document the workflow for creating dot density maps with ArcMap. This seemed to be easy enough and in fact was quite easy given ArcGIS provides the tools necessary for completing this task. Continue reading

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Dot maps vs. choropleth maps with random dot area symbols

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

Question: What is the difference between filling a polygon with randomly placed dots and creating a dot density map for the polygon?

Filling a polygon with a certain number of randomly placed dots is a form of choropleth mapping where random dots are the area symbol for a quantity that is assumed to be of uniform density throughout the polygon. The choropleth map seen below of San Bernardino county population density uses random dots in this manner. Continue reading

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Getting better vectors from your rasters with ArcScan

By Aileen Buckley, Mapping Center Lead

Getting Better Vectors - Thumbnail

I’ve often had the situation where I wanted to use a raster data source as a single-color map background layer, but the cell size or other data processing output resulted in a ‘blocky’ or ‘pixelated’ appearance to the data at the map scale I need. A simple raster-to-vector data conversion served only to recreate the boxes or ‘saw-tooth’ or ‘stair-step’ lines from the original raster. The ArcScan extension has tools that reduce or remove this problem, and create an output vector data layer with smooth polygon boundaries or more naturally sinuous lines.

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Can you read me now?

By Charlie Frye, Esri Chief Cartographer

Text and imagery have had an uneasy relationship since the day they met. Satellite imagery and aerial photographs are the ultimate variable background, which makes any text drawn on them hard to read.

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