Tag Archives: ArcGIS Methods
Esri Production Mapping
By Greg Tieman, Technical Manager, Mapping & Charting Solutions
For this blog topic, we’d like to introduce you to Esri Production Mapping and outline some of its benefits for map and data production. Production Mapping provides several cartographic capabilities that will be covered in upcoming blogs. For now let’s just talk about what this product is.
Creating a web map service
By Aileen Buckley, Mapping Center Lead
In our previous blog entry, we discussed Designing Operational Overlays for the ArcMap and ArcGIS Online Basemaps. Once you are satisfied with your final symbology and labeling, you’re ready to publish your map to the Web. The process involves using ArcGIS Server to publish your map as a map service – a format that can be viewed on the Web. Each map service will have a unique record locator (URL) that others can use to view your map in a Web browser or in ArcMap, ArcGlobe, or ArcGIS Explorer (figure 1).
Virtual dissolve for polygon fill and boundary lines
By Kenneth Field, Esri Research Cartographer
We received a question on Ask a Cartographer recently which were both asking if it was possible to take a group of polygons and create an outline for the whole group rather than have outlines for each polygon.
The most obvious answer is that you can use the Dissolve tool on a common attribute to create a new feature class, but what happens if you don’t want to create a new dataset solely for dealing with the cartography? There is another way which eliminates the need to create a new feature class and is based on an Esri Knowledge Base article that describes how to symbolize polygon features so that boundary lines between polygons with like attributes are dissolved. We thought it worth exploring the solution in a little more depth in this blog to demonstrate how it works. We’ll illustrate the workflow using the New England states of the USA at a county level to create a map at the state level (figure 1).
How to fix ZIP codes from a CSV file
By Jim Herries, Esri Cartographic Product Engineer
Comma-separated value (.CSV) files are sometimes used to import attribute data into ArcMap to join those attributes to existing map features, such as administrative boundaries (counties, states, provinces) and postal codes. However, chances are good that if you work with .CSV files you will run into the problem below at some point.
Classifying Landsat image services to make a land cover map
By Rajinder Nagi, Esri Cartographic Product Engineer
In a previous blog entry, we discussed how you can use Landsat image services in ArcMap to see the change over time. In this blog entry, we dive further into Landsat image services and describe how you can create thematic land cover maps which can then be used for analyses, such as land cover change detection.
The image classification process involves conversion of multi-band raster imagery into a single-band raster with a number of categorical classes that relate to different types of land cover.
Curious? Our most popular blog posts to date
By Aileen Buckley, Mapping Center Lead
I was looking through the list of our blog posts, and I thought you might be interested to see which ones have gotten the most “hits”. I’ll list them here, but keep in mind that some of our older posts get higher numbers of hits because, well, they’ve just been around longer! But I think this list also helps us learn what you want to hear about. If anything in the list generates an idea about something you would like us to blog about, please send us comments to this post so we can hear from you. So, here we go…
Symbolizing point features using ground units: Multiple symbols
By Aileen Buckley, Mapping Center Lead
We got an interesting question on Ask a Cartographer last week: Can I symbolize points in map units? Greg wrote “I want to show point features with a specific size expressed in [ground] units (e.g., 660 ft), but I do not want to create a buffer layer to achieve the same effect. Is it possible symbolize points in [ground] units?”
If you are using only one symbol, you can do this using our Proportional Symbol renderer, as we described in our previous blog post. If you have more than one symbol, you have to take a slightly different approach. Here’s how you do it…
In ArcGIS 10, you can do this using an expression and a size field in your attribute table. You will use a formula that will convert your size in ground units to points (72 points to one inch) which are the units used for symbols.
Symbolizing point features using ground units: Single symbol
By Aileen Buckley, Mapping Center Lead
We got an interesting question on Ask a Cartographer this week: Can I symbolize points in map units? Greg wrote “I want to show point features with a specific size expressed in [ground] units (e.g., 660 ft), but I do not want to create a buffer layer to achieve the same effect. Is it possible symbolize points in [ground] units?”
If you are using only one symbol, you can do this using our Proportional Symbol renderer. If you have more than one symbol, you have to take a slightly different approach, which we will talk about in our next blog entry. For the proportional symbol approach, here’s how you do it…
Making the scale bar the right length in ArcMap
By Aileen Buckley, Mapping Center Lead
I’ve addressed issues of scale bars in a couple of our earlier blog entries (Choosing the best way to indicate map scale and Back to the Issue of Scale Bars). In this one I tell you how you can make sure that the scale bar you insert is the right length on your map. But before I do, I want to first point out that for the most part the only maps that should include scale bars are those for a smaller extent and therefore generally at a large scale. If you map a larger extent then the scale distortion over that extent will mean that the scale bar is not valid for the entire area mapped. A complicating factor is the differing scale in different directions on small scale maps – another reason not to put scale bars on small scale maps. We generally define “large scale” as 1:250,000 or larger for just these reasons – on maps at these scales, you can make accurate distance and area measurements.
Making the Tissot's Indicatrices
By Aileen Buckley, Mapping Center Lead
Some of you might wonder how I created the indicatrices (ellipses) in the Tissot’s Indicatrix blog entry. It’s based on creating geodesic buffers from point features that are in a geographic coordinate system. If you review the blog entry on the different tools for creating buffers with ArcGIS, you will see that:
“If point or multipoint features are being buffered, if the data are projected to a geographic coordinate system, and if a buffer distance is specified in linear units, the Buffer tool will create geodesic buffers…A geodesic distance is calculated across the curved surface of the earth.”
