August 2007 - Posts

Geoprocessing to split elevation into topography and bathymetry

When an elevation raster dataset contains values for both topography and bathymetry, often the best solution to this is to split it into two new rasters:  one for the topography and one for the bathymetry. The reason is that symbolizing this data is difficult. This is because a color ramp that contains appropriate hues for both bathymetry and topography must be adjusted so that it shows the shoreline exactly in the right place, at zero elevation. Read More...

Posted Wednesday, August 29, 2007 6:23 PM by cfrye | 0 Comments
Filed under: ,

Displaying Coincident Points

We've had a number of folks writing in on Ask a Cartographer wondering how to displace or offset coincident points so all the points could be seen. Data with coincident points is most commonly produced as a result of geocoding addresses. There are at least two ways to handle displaying this data.  One would be to create a graduated or proportional symbol thematic map, and to do that the input point data would be processed with the Collect Events tool, which would produce output containing points that represented the locations and an attribute that indicated how many points were at that location. Read More...

Posted Monday, August 27, 2007 9:19 AM by cfrye | 2 Comments

Gulf of St. Lawrence locator map is available

The Gulf of St. Lawrence map was originally created for an ESRI tutorial on how to publish a map to ArcReader. The intent was to include a simple locator map with a few basic functions. These cartographic effects and tasks are highlighted: Creating stacked Read More...
Posted Friday, August 24, 2007 9:36 AM by cfrye | 0 Comments
Filed under:

ScaleMaster

At the users conference this year we showed, in our technical session on lessons learned in cartographic data modeling, a tool we've been using for a few years now. It's called ScaleMaster, and we initially developed it to examine the idea that different Read More...
Posted Wednesday, August 22, 2007 12:11 PM by cfrye | 0 Comments
Filed under:

Organizing layers with too many unique values

If you make zoning, soils, geology, or any of a number of kinds of maps where your data represent many different types of features, you can make use of some specialized functionality in the unique values symbology method in ArcMap's layer properties symbology Read More...
Posted Monday, August 20, 2007 3:03 PM by cfrye | 4 Comments
Filed under:

We’re back from the International Cartographic Conference in Moscow, Russia

For those of you who may not have heard of the ICC, it is the meeting of the International Cartographic Association (ICA). The ICC happens every two years, moving from continent to continent -- for example the 2009 meeting will be in Santiago, Chile. Read More...
Posted Wednesday, August 15, 2007 2:01 PM by MappingCenterTeam | 0 Comments
Filed under:

Verbal Scales

A verbal scale is also referred to as a “word statement” or a “scale expression”, and in the ArcGIS software, it is one of the options for inserting “scale text”. It is offered in the form of a relationship between map distance and ground distance stated Read More...
Posted Tuesday, August 14, 2007 1:59 PM by MappingCenterTeam | 0 Comments
Filed under:

Representative Fractions

A representative fraction (RF) is the ratio of distance on the map to distance on the ground. Representative fractions are expressed in the form of 1 followed by a : (colon) and then a number, where the one is the numerator in the fraction, the colon Read More...
Posted Sunday, August 12, 2007 1:50 PM by MappingCenterTeam | 1 Comments
Filed under:

Choosing the best way to indicate map scale

In a previous blog entry , I asked, “Do all maps need a scale bar and north arrow?” I answered, “No” and talked a little about direction indicators like north arrows, but I didn’t really go into any detail about scale bars. Here is a bit more on map scale Read More...
Posted Monday, August 06, 2007 1:45 PM by MappingCenterTeam | 4 Comments
Filed under:

Symbolizing the Results of a Hot Spot Analysis

There are a number of spatial statistical analysis tools now available in ArcGIS. Some, like the Hot Spot Analysis tool produce specially structured results that can be misinterpreted or misrepresented if you approach symbolizing them in a generic way, Read More...
Posted Wednesday, August 01, 2007 1:38 PM by MappingCenterTeam | 0 Comments