Mapping Center

One of the most frequently recurring topics on Mapping Center is what to do with stacks or clusters of point features on maps. In August 2007, I wrote a blog posting on how to use Maplex to display coincident points, and this worked for some scenarios, but not all. Read More...

Not long ago we found a workflow that demonstrated how convenient it would be to be able to copy a representation class. The situation arose as we were creating a map service for a map that had been designed for print. The problem was that many of the symbols were too small and detailed to be seen clearly on screen. Our symbols were already cartographic representations, so we didn't want to edit them (to make them larger) because we still needed them to produce our print map. We also didn't want to have to create and manage an extra copy of our data just to manage one additional attribute (the one added for representations). Read More...

Put yourself in the shoes of one of my interns, who was asked to use representations to replicate a 1:100,000 scale geologic map.  In less than two weeks she got it done, and did so well that the next thing I asked her to do was to test ArcGIS Server and make a map service with her map. Those intricate little point symbols on geologic maps that are rotated by their strike angles and labeled with their dip angles were just too small to be seen clearly on screen.  We needed to make them bigger. Read More...

Not too long ago we received a question on Ask a Cartographer about symbolizing polygons with a scalloped edge (like the old ArcInfo hardwire line symbol). Hoping to do better (scallop lines were a nice idea, but they didn't always turn out as good as I would have liked, so I rarely used them), I started experimenting with the options in representation symbology. I'm happy to report that there is a better solution. Read More...

Last week we received a good question on Ask a Cartographer: is there a way to create parcel hooks with ArcGIS 9.2? After first discovering what parcel hooks were and finding an example of a typical case (shown at left), the answer seemed like a ‘no-brainer'. Sure, just use the line decoration option on a marker line representation. However, after acquiring some parcel data that included parcel hooks (thanks to Greene County, NC) and seeing the circumstances where parcel hooks (they're also called land hooks or parcel ties) are placed on maps, I learned there are are several scenarios that need to be handled. Read More...

Quite some time ago we posted a blog entry on creating tint bands, which are bands of color either interior or exterior to polygons along their borders.  You will see this cartographic effect on world atlases, for example, using different colors to distinguish the various counties. The solution we presented was involved and complex, but it did preserve essential characteristics of the polygons better than any other method we tried. Read More...

Cynthia Brewer’s new book titled Designed Maps: A Sourcebook for GIS Users is a companion piece designed to compliment the highly successful Designing Better Maps: A Guide for GIS Users published by ESRI Press in 2005. The goal of the book is to offer a graphics-intensive presentation of published maps, providing cartographic details that will prompt GIS users to think about their own maps and how to improve them. Read More...

Using cartographic representations to make line symbols like those in the image to the right, where markers are displayed in conjunction with a dash pattern, requires more than just casual knowledge of the geometric effects. In fact, to make a line symbol like the one shown to the right, the default settings won't work. Read More...

For the past few years, when time allowed, I've been reconstructing a map of colonial Boston in ArcGIS, using source maps from 1775 to 1784.  The image on the left is an excerpt of one of these maps.  I like a number of the effects that 18th century cartographers had drawn on their maps, including little pictographs for trees (today cartographers call these mimetic symbols).  Anyway, I wanted to add some of these effects to my map.  This posting explains how I showed trees on my map.
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A question was posed on Ask a Cartographer about using representation rules that you have saved in a style in another map on a different layer.  The online help for this topic didn't provide much assistance. The topic on organizing representation rules in a style explained how to load the rules in to a new layer, but it didn't explain how to make use of them, i.e., how to make the features with the newly loaded rule. Read More...

The map excerpt shown at right (click on it to see the details) shows an example of hollow cased roads.  The map is from a mosaic of USGS DRG image files.  The map specification requires that the cased road symbol contains a transparent gap.  The examples shown below were created with ArcMap 9.2 and used cartographic representations to re-create the effect on the USGS DRG map. Read More...

This final part of the series will cover using cartographic representations for dashed lines, like the red and white cased lines in the image at the left, and for creating cul-de-sac or squared off ends to streets.  Both of these effects will build on the examples in the previous two portions of this series with one exception.  Because we will be using cartographic representations for the streets, we will be better able to manage line caps and therefore will not need to use the Dissolve tool to dissolve the streets by name, type, and z-level.  The removal of this step is significant because now an extra dataset is not required just to have cartographic quality streets; everything needed for a high quality cartographic depiction of streets can be stored in attributes. This should come as good news to those of you who have mentioned to us, many times, that managing additional datasets for the sake of cartography is not only a data management, but a political hurdle, that you would just as soon not have to deal with. Read More...

A number of maps, particularly those geared towards outdoor tourism, rely on a convention that uses standard icons to list the services or amenities that are available at some place on the map. Using cartographic representations simplifies what used to be a rather unwieldy task from the perspectives of data modeling, data management, and symbology. Read More...

If you want to remove selected features from display with standard ArcMap symbol management tools, you need to use the Layer Properties to do so.  Typically this might mean using a Definition Query based on a feature attribute value, or a classification scheme which excludes a range of attribute values.  Cartographic representations provide you with a method for removing features from display, this method is based on graphic selection.

You could use this functionality in the case where you want to create a map for a time or scenario that is not reflected in your current data.  For example, the Crater Lake National Park data which we use in Mapping Center is recently captured National Park Service data.  If I want to re-create a Crater Lake National Park map from the 1950s Read More...

A number of you have written in to Ask a Cartographer wishing to know how to convert your font-based or EMF-based marker symbols to representation markers.  Representation markers (introduced in ArcGIS 9.2) have a number of advantages over font- or graphics-based markers.  For example, you can create or edit their artwork while working in ArcMap or ArcCatalog, and they can be used the geoprocessing framework.  One geoprocessing tool engineered to work with cartographic representations which you might find particularly useful is the Detect Graphic Conflict tool, which tells you where the symbols on your map overlap one another.  But first, many of you may need to convert a significant number of markers into representation markers. Read More...