Category: Mapping

Simplifying lines and polygons that intersect with other lines and polygons

By Charlie Frye, Esri Chief Cartographer

Example of hydrographic data compiled for 1:5,000 scale maps

There are quite a few tools in the ArcGIS toolbox that are designed to, and depending on your goal, work well for generalizing a single feature class. The downside to that is many feature classes of data can be required make a given map and all should be displayed at a level of detail that is appropriate for the map scale. Simplifying one feature class at a time will not account for intersections between two line feature classes, two polygon feature classes, or a line and a polygon feature class. What follows is a method that can be used to simplify the lines in two feature classes while preserving the location of any intersections. Essentially what you will do is to put all the features into one feature class, generalize that, and then split them out into the final feature classes. Continue reading

Posted in Mapping | Tagged , | Leave a comment

Displaying a perimeter for all polygons in a dataset

By Charlie Frye, Esri Chief Cartographer

The goal is to show just the perimeter for all the polygons in the dataset

We were asked, not long ago:

“I’ve got a dataset with polygons that represent the extent of field study areas at different dates; these study areas have grown over time and I want to show a single polygon that represents each site’s current study area, while still allowing me to Identify anywhere within the area, be able to see other features inside of the study areas, and I cannot be saddled with a geoprocessing experience every time I need to make my status maps for any of the study areas; How can I do this?” Continue reading

Posted in Mapping | Tagged , , | Leave a comment available in ArcGIS 9.2

By Charlie Frye, Esri Chief Cartographer

Quite a few people saw technical sessions in San Diego at the Users Conference where the was mentioned. A number of you have written in, asking, “What exactly is it?” and “Where can I find it?” Continue reading

Posted in Mapping | Tagged , , | Leave a comment

Choosing an appropriate cell size when interpolating raster data

By Charlie Frye, Esri Chief Cartographer

Choosing a raster cell size is a parameter in many tools

“If I want to create a digital elevation model (DEM) by interpolating from a point shapefile (digital terrain model or DTM), how can I select the most correct cell size given the original separation of the point file?” We recently received this question via the Ask a Cartographer Web page, so we checked with a couple of the product engineers on our Spatial Analyst development team and found that we didn’t have a help topic addressing the subject. Moreover, the answer was not simple—it varied depending upon why the DEM was needed. Continue reading

Posted in Mapping | Tagged , , | Leave a comment

Making maps that show flow from place to place

By Charlie Frye, Esri Chief Cartographer

Example of expressive flow arrow in a map made using ArcGIS

We’ve received a few requests this week asking how to use ArcMap to show flow from place to place. The requests ranged from, “What might the data look like?” to “How do I make the flow arrows?” One thing to note, this isn’t a topic that I have much first-hand experience with, but I can certainly get things started with the hopes that others will add their experiences and perhaps, together, we can build a body of knowledge to benefit us all. Continue reading

Posted in Mapping | Tagged , , | 3 Comments

Heads up color proofing for Esri style's colors

By Jenny Reiman, East-West Gateway Council of Governments

Layout from ColorPalette_ArcGIS.mxd

Here’s a useful little map document called ColorPalette_ArcGIS.mxd that I put together to anticipate the variation between colors on my monitor and the printers and plotters in the office. It contains no geographic data, only graphics that correspond to the standard color palette in ArcGIS. Each color swatch is labeled by name and by CMYK values. I print a copy from each printer and hang them near my monitor so I can choose colors for my layout based on what they look like on paper, not just based on what the colors look like on my monitor. Someday everything may be perfectly calibrated with a color matching system like Pantone. Until then, this helps – and it makes great cubicle wall paper!

Posted in Mapping | Tagged , , | 2 Comments

Finding depression contour lines

By Charlie Frye, Esri Chief Cartographer

Note the two depression contour lines with ticks pointing downhill

Unfortunately there currently is no automated way in ArcGIS to evaluate contour lines and select those that are depression contour lines. There are some tools in the Spatial Analyst extension such as FLOW DIRECTION, SINK and FILL which may look useful for this purpose, but in fact are designed to find small irregularities in digital elevation models (DEMs) and fix them, and thus they don’t find larger depressions, which are typically the basis for depression contour lines. Continue reading

Posted in Mapping | Tagged , | Leave a comment

Gradient fills add cartographic allure

By Charlie Frye, Esri Chief Cartographer

World K-12 Education 1

Esri’s Graphics team needed some maps for a slide for one of this year’s Users Conference presentations to show where GIS was being used in K-12 programs in the U.S. and throughout the world. I was asked to spruce up the maps for the slide and was told these maps should be really simple because everyone in the audience would be looking for their country, or in the case of the U.S., their state or city, so no text would be needed, in fact just provide TIFF files of the maps.

I joined the K-12 data to the template data that ships with ArcGIS Desktop. You can usually find this in C:Program FilesArcGISbinTemplatesData, I just used the states, countries, and world30 datasets. I was given a point shapefile for the U.S. data. Continue reading

Posted in Mapping | Tagged , | Leave a comment

Cartographic Relief Presentation reissue: Answers to a few recent questions

By Charlie Frye, Esri Chief Cartographer

Gradient Cartographic - Figure 3

Almost as soon as we announced the availability of Esri Press’ reissue of the English translation of Eduard Imhof’s Cartographic Relief Presentation, we started receiving some good and interesting questions. In the nearly four-plus years it took to complete this project, a number of rumors circulated that produced some of these questions. So, here are a few of those questions and our answers:

Q: The write-up on the Esri Press page states, “This new edition of Cartographic Relief Presentation was edited for clarity and consistency,” what does that really mean?

A: The Esri Press team found and fixed issues with punctuation and grammar. They did so, only when the meaning of a given sentence was clear; if the meaning was not immediately clear, then no change was made. Continue reading

Posted in Mapping | Leave a comment

Setting the Z Factor parameter correctly

By Charlie Frye, Esri Chief Cartographer

Z factor - Thumbnail

We set the Z-Factor parameter based on our latitude.

The Z-Factor parameter is in many Spatial Analyst and 3D Analyst tools; Hillshade and Slope are the two that I use most. Not setting the Z-Factor correctly makes the hillshades look heavy or leaden. It will also make slope values, e.g., for percent slope very small, like 0.00023% – 0.00032% instead of 1.8% to 7.2%.

Continue reading

Posted in Imagery, Mapping | Tagged | 8 Comments