Mapping Center

Copying a representation class

cfrye — Wed, 02 Jul 2008 20:10:00 GMT

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)

Representations Tip: Using data-driven settings to transition printed maps to map services

cfrye — Fri, 27 Jun 2008 00:35:00 GMT

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)

Strategy Question: What is the best way to manage overflow annotation on street maps?

cfrye — Fri, 20 Jun 2008 01:20:00 GMT

We got one of those perennial 'tough nut' questions on Ask a Cartographer today. The question had to do with annotation versus Maplex and what are often called overflow labels, which I have also heard called "key lists". While we are able to recommend tips and tools for specific circumstances or implementations, the person asking was more interested in what is the best strategy and why. So here's their question:

"We produce a 1"=1000' City map book from our GIS, similar to the Thomas Bros. street guides. ...(read more)

Migrating Illustrator Files (.ai) to ArcGIS

cfrye — Wed, 18 Jun 2008 23:00:00 GMT

Last month I was lucky enough to be invited to the USGS's Digital Mapping Techniques (DMT) conference. Unless you do geologic mapping this conference is likely not on your radar, but suffice to say it worth the effort to get to Moscow, Idaho on many counts. One is that I met Andrew Wunderlich, who gave a great and detailed presentation on how he has been migrating a base of Adobe Illustrator files to ArcGIS....(read more)

Expressing Slope

pkasianchuk — Thu, 12 Jun 2008 17:32:00 GMT

The vertical change in the elevation of the land surface, when determined over a given horizontal distance-along a road or stream, for instance-is known as its slope (Figure 1). There are three primary ways to quantitatively express the slope between two points. In each, the lower the slope value, the flatter the terrain, and the higher the slope value, the steeper the terrain. The slope values may be expressed as a ratio, as a percentage or as an angle. ...(read more)

Simplifying polygon map layers

frantsdk — Wed, 11 Jun 2008 00:30:00 GMT

I have recently "invented" a method for simplifying polygon map layers, which seems to give reasonable results. Probably many others have invented it before me, but I would like to present it in order to receive comments and advice on setting the appropriate parameters.

My task was to produce a national soil map suitable at 1:1,000,000 scale on the basis of a 1:200,000 map. The best method would probably be to have a geologist or soil scientist make a complete re-production for the new scale - but we needed a less expensive method. The challenge was to find a technique that would not totally erase soil types represented as many small polygons covering more than half of the area in some regions....(read more)

Symbolizing a tree canopy

cfrye — Wed, 04 Jun 2008 17:30:00 GMT

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)

"Angeles River, Los"

cfrye — Sun, 01 Jun 2008 21:00:00 GMT

Making maps with data that were never intended for mapping has it's challenges. One of them is trying to use the names from GNIS (Geographic Names Information System) (U.S. Board on Geographic Names). Even when someone has gone to the effort of assigning these names to GIS features, the way the names are formatted can create problems. In the case of the GNIS, the names were formatted for an old-style (i.e., pre-modern search engine) alphabetical index that you could visually scan like a gazetteer in an atlas. The result is that there are entries like "Great Salt Lake, The" or "Grande, Rio" which need reformatting in order to look correct on a map....(read more)

Spring conference presentations

abuckley — Fri, 30 May 2008 23:28:00 GMT

This spring, we have caught up with many of you at a number of conferences. The presentations we gave at the conferences are now posted on the Other Resources page here on Mapping Center. Here's a rundown of our latest activities... In April, we attended the Association of American Geographers meeting in Boston. There we gave a presentation on "Web Delivery of Cartographic Concepts and Best Practices". Then we saw some of you at Carto 2008, jointly sponsored by the Canadian Cartographic Association and the Association of Canadian Map Libraries and Archives...(read more)

I remember making this feature class...I wonder why?

cfrye — Thu, 29 May 2008 00:45:00 GMT

Have you ever wondered where a feature class came from as you've browsed over one of your geodatabases in ArcCatalog? I think most of us have, and probably more often than we'd like to admit. In the example shown here to the left, I made these datasets a few weeks ago, and I have no idea what "GN" means, and if or how I selected, simplified, or dissolved the data.

There are a couple of things we can do to avoid that puzzled feeling: standardize your feature class naming convention; standardize your geoprocessing. With the naming convention, I started doing the right thing here, but failed to follow through and leave myself the necessary clues. The data in the image above was also the result of a complex workflow, so rather than start with that, let's cover the basics....(read more)

Aspect-Slope Map

abuckley — Fri, 23 May 2008 00:30:00 GMT

An aspect-slope map simultaneously shows the aspect (direction) and degree (steepness) of slope for a terrain (or other continuous surface). Aspect categories are symbolized using hues (e.g., red, orange, yellow, etc.) and degree of slope classes are mapped with saturation (or brilliance of color) so that the steeper slopes are brighter. This will result in a map that has the colors shown to the right....(read more)

Dot maps for U.S. General Soil Map (STATSGO) data

lindabarrett — Thu, 15 May 2008 13:00:00 GMT

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....(read more)

Color ramps reorganized

Jaynya — Tue, 13 May 2008 13:00:00 GMT

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....(read more)

Hypsometric Tinting

abuckley — Fri, 09 May 2008 19:01:00 GMT

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....(read more)

Tips for getting better map drawing performance

cfrye — Tue, 06 May 2008 22:45:00 GMT

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....(read more)