Mapping Center

Bar chart legends

abuckley — Mon, 08 Feb 2010 09:00:00 GMT

We recently received this question on Ask a Cartographer:

"I am using a bar chart with 2 data fields to display data on my map. In the legend, I have my 2 data fields displayed, and there is a random number (not sure if it is a mean or median of one of my data columns) which is also displayed in the legend, and I cannot remove it. I'd like to remove this random number from the legend. Can anyone help?"

In this blog post, we'll go into a little more detail about charts and their legends since this seems to be a question that has been raised before (http://forums.esri.com/Thread.asp?c=93&f=989&t=273493 and http://forums.esri.com/Thread.asp?c=93&f=1730&t=262441)....(read more)

Simultaneously displaying hillshades of multiple resolutions and extents

makella — Fri, 05 Feb 2010 01:00:00 GMT

I have been working on an online, multi-scale map of Yosemite National Park. This map will be incorporated into the World Topographic Map at map scales of approximately 1:9,000, 1:4,500, 1:2,000, and 1:1,000. From Yosemite National Park, we received elevation data at two grid cell resolutions: ten meter data for the entire park and 1 meter LiDAR data for seven or eight smaller areas within the park.

Figure 1 shows examples of these two data sets. The hillshade symbolized with the black to white color ramp was generated using the 10 meter DEM data, and the smaller extent symbolized with red tones was created using the LiDAR data....(read more)

Symbolizing world water

abuckley — Mon, 01 Feb 2010 21:31:00 GMT

I am working on a small scale map of the world that shows political boundaries over time from about 2000BC to the present. For this map, I want to show the world's water with a bit of variation along the coasts. This is desirable for a couple of reasons: 1) to better indicate where the islands are, and 2) to provide better figure-ground by separating the land areas visually from the ocean areas.

And easy way to do this is with a coastal vignette, as we have discussed previously (Symbolizing Shorelines). In this blog entry, I demonstrate an easy way to achieve this effect for the ocean waters of the world. There are a couple of things you have to do to "clean things up" if you are working at a global extent -- specifically, the vignettes will extend beyond the "edge of the world"!...(read more)

A Concise History of Bump Mapping

nighbert — Wed, 27 Jan 2010 08:00:00 GMT

Hi, folks— I have never blogged before so forgive me if I ramble on too much. I have been working with ESRI to convert ideas and snippets of code from my past work presented at the ESRI International User Conferences into a usable set of tools for all to use. This is a great honor indeed, and I thank them for the opportunity. My ideas on landscape presentation have now taken on a life of their own as a set of tools in an ArcToolbox that you can download from Mapping Center. I hope others will find them easy and fun to use. To learn more about them you can read two blog entries that were posted earlier: Introducing the ArcGIS Bump Map Tools and Symbolizing the Bump Map....(read more)

Symbolizing the Bump Map

abuckley — Mon, 25 Jan 2010 08:00:00 GMT

In our previous blog post, we introduced the ArcGIS Bump Map tools and described the structure of the model and how to run it. Now we want to talk about how you can symbolize the results and use additional tools to create stunning bump maps! The Bump Map Tools can be downloaded from the ArcGIS Resources-Model & Scripts page of Mapping Center. Symbolizing the results of bump mapping involves three steps – 1) symbolizing the hillshade, 2) symbolizing the elevation with a hypsometric tint, and 3) symbolizing the vegetation overlay with a layer tint or other color. Symbolizing the hillshade is fairly straightforward and we have discussed many options for how you can do this in previous blog entries, so we won't go into that here. To symbolize the bumped surface, you have a number of options, so we do want to explore that in more detail. You have the potential to create a very realistic looking surface fairly easily!...(read more)

Introducing the ArcGIS Bump Map Tools

rajnagi — Thu, 21 Jan 2010 08:00:00 GMT

We are pleased to announce the release of the new ArcGIS Bump Map Tools! This new toolbox contains tools to help you create and symbolize "bump maps" which are used by cartographers to add texture to a hillshaded surface. This technique is most often used to give the illusion of a realistic vegetated surface, though Jeff Nighbert has also talked in some of his papers and presentations about using it to represent rocky outcrops and other surfaces as well. Jeff introduced the technique to ArcInfo users at the 2003 ESRI User Conference (see links to his papers and presentations on the Mapping Center – Other Resources page)....(read more)

Using tables in an ArcMap layout

abuckley — Tue, 19 Jan 2010 01:10:00 GMT

We recently received a request for some help on tables on Ask a Cartographer. We thought we could pass along some of the tips in a blog entry as well, especially as there is currently limited info in our online help about tables (but we are working on changing that!) Here are a dozen elementary but critical "how to's" for working with tables in a page layout.

1. What are the basic concepts that relate to tables in a layout view?

A table is a display of attribute information in a tabular format. The information displayed in a table comes directly from the attribute information stored with your geographic data. The table contents will update if you make a change to the attribute table.

Tables are different from reports, which are derived from a table in your map and then stored in the format of a graphic element (so they are not "live-linked", so to speak). Once you've created a report, you can place it on your map layout or save it as a file for distributions....(read more)

How do you put a north arrow a map with the UPS grid coordinate system?

abuckley — Thu, 24 Dec 2009 20:00:00 GMT

We received this very interesting question the other day on Ask a Cartographer: "What is common practice for map orientation and the use of north arrows for maps using the UPS projection? Do you keep grid north up and turn the north arrow accordingly, or do you rotate the map so true north is up and so the UPS grid is tilted like with the UTM projection? With UPS the rotation could be very large, up to 180 degrees."

For those of you not quite familiar with the terms, "grid north" is the positive northing direction of a grid coordinate system used on a map. The Y or northing values of the projected coordinate system increase in the direction of grid north. "True north" is a fixed location on the earth—the north pole. The meridians of the graticule (the arrangement of parallels and meridians) converge at true north. In a cylindrical projection like Mercator (Figure 1) which has straight up-and-down meridians, the direction of true north is the same as grid north....(read more)

Location of Alaska on USA maps

ajskinner2 — Wed, 16 Dec 2009 20:00:00 GMT

At the recent Northwest GIS User Conference, Dorothy Mortenson commented on the location of Alaska on U.S. maps. Dorothy works for the Oregon Water Resources Department and is often tasked with mapping the Pacific Northwest, including Alaska. She made some very good points about why we should try to change the standard practice of placing the state of Alaska in the lower left corner of the page. We agreed with her when she made a case for changing the map layouts and we wanted to share our thoughts with you. But first, here are a few of the points Dorothy made:...(read more)

Mathematical Relationships among Map Scale, Raster Data Resolution, and Map Display Resolution

kimerlia — Fri, 04 Dec 2009 02:00:00 GMT

If you have used any raster data to make maps you may have at one time or another asked yourself, "What is the appropriate resolution of raster data for the map I am making?" This question is tied closely to a basic principle of map compilation that you may have learned in your beginning cartography course: "Always compile your map from source materials of the same or larger map scales". In our age of digital elevation models and other raster datasets, this basic principle of map compilation can be restated as: "Always create your raster map from data at the same or higher spatial resolution than the ground resolution of your map display grid cells". The ground resolution of your map display grid cells will depend on the scale of your map. An equation you can use that relates map scale (1/x), raster data resolution, and map display resolution is shown in the full blog entry....(read more)

Symbolizing trees in ArcGIS: Randomly varying the tree symbol size

makella — Wed, 02 Dec 2009 01:00:00 GMT

On large scale maps, you will often see that the symbols used to represent trees are one size. As we know from our own real-world experience, tree crowns (i.e., the top of a tree formed by its leaves and branches) are different sizes, so a more realistic representation would be to vary the tree symbol size slightly to account for this natural variation.

Although we know that the height, trunk diameter, and crown diameter all vary depending on the amount of sunlight a tree gets, what age it is, and where it is planted (to name a few variables), what if none of this information is available to create variation in your tree symbols? What can we do in ArcMap cartographically to at least show varying crown sizes for our symbolized trees? This blog entry describes a method to symbolize trees using point symbols that give the impression of varied tree crown sizes....(read more)

Symbolizing the Hillshade for the World Topographic Map

cfrye — Tue, 24 Nov 2009 21:04:00 GMT

One of the things I promised myself that I would do last summer was write about some of the key design solutions used in the World Topographic Base Map. Our symbolization of the hillshade is one of the design characteristics that most distinguishes this map. The design intent was two-fold: 1) show shading similar to how hatchures were used on hand-drawn maps [to see what I mean one of my favorite 18th century maps depicting the Battle of Bunker or properly Breeds Hill is a good example], and 2) display the low slope areas in white because this creates a "non-competitive" background for data that is mashed up on this base map...(read more)

Using the Buffer Tool in ArcToolbox (and comparing with the Buffer Wizard in ArcMap)

marg3002 — Wed, 18 Nov 2009 23:00:00 GMT

In this blog entry, I discuss using the Buffer Tool in ArcToolbox. I also compare the ArcToolbox Buffer Tool with the Buffer Wizard in ArcMap. The Buffer Tool, located in ArcToolbox > Analysis Tools > Proximity toolbox uses different methods to calculate buffers. The method used by the tool depends on the type of feature being buffered.

An important thing to understand is that when creating buffers for line and polygon features, the Buffer Tool in ArcToolbox uses the coordinate system of the data being buffered by default. When points are being buffered, another method is used which will be described later in this article....(read more)

Symbolizing trees in ArcGIS: assigning each species a different symbol

makella — Thu, 12 Nov 2009 05:00:00 GMT

Tree symbols are a great way to enhance the appearance of a large scale, detailed map. To make attractive point symbols for trees, you need a good place to start from and thankfully all of us ArcGIS users have that. Using multi-layer character marker sybmols, the variety of tree symbols you can create is endless. This blog is meant to introduce (or reintroduce) you to the ESRI US Forestry 2 font. It is also meant to give you some tips for creating a variety of tree symbols to use on your maps....(read more)

Announcing the ArcGIS Data Blog

cfrye — Fri, 30 Oct 2009 17:00:00 GMT

September and October sure went fast. We on the Mapping Center team have been very busy working on mapping projects, and have not spent as much time here--but we're finding a balance and will be getting more good blogs out here soon (several are in the pipeline).

Now there is a new blog, the ArcGIS Data Blog, that you should subscribe to in order to keep up on what's new with all of ESRI's data--this will give you an advantage by being able to produce better maps because you've got better content to use...(read more)