Sorry about the old posts making it into the feed. I’ve spent the better part of the past week rebuilding the site from the ground up, and parked it temporarily at a different IP address; I’m guessing that caused the repeat listings of old posts. Should be done with the rebuild, and semi-regular posting will resume immediately; regular posting may have to wait until my current field survey work is done in 2-3 weeks.
Archive for the 'ESRI' Category
As a demo of the ArcGIS API for Flex, ESRI has a new page that lets you create an embeddable/shareable map of demographic data by US county. Only seven datasets available now:
- Median Household Income
- Population Change 2000-2009
- Population Density (per sq. mile)
- Median Home Value
- Unemployment Rate
- Average Household Size
- Median Age
Map creation is trivially easy – select the demographic dataset from a dropdown, zoom the map to the desired extents, set a map size in pixels, and you’re done; links to a map with your parameters, and code for an embeddable map, are generated automatically. Here’s an embedded map, scrollable and zoomable; unemployment rate is the defaultdataset, but you can choose other sets with the dropdown menu at upper right:
More datasets would be nice, as would control over colors and ranges …
The Sampling Design Tool is another free ArcGIS extension from NOAA’s Center for Coastal Monitoring and Assessment, the source of the Habitat Digitizer Extension I posted about last week. Key features (from the PDF manual):
- Spatial sampling –sampling and incorporation of inherently spatial layers (e.g.
benthic habitat maps, administrative boundaries), and evaluation of spatial
issues (e.g. protected area effectiveness) - Scalable data requirements – data requirements for sample selection can be
as simple as a polygon defining the area to be surveyed to using existing
sample data and a stratified sample frame for optimally allocating samples - Random selection -eliminates sampling biases and corresponding criticisms
encountered when samples are selected non-randomly - Multiple sampling designs – simple, stratified, and two-stage sampling
designs - Sample unit-based sampling – points or polygons are selected from a sample
frame - Area-based sampling – random points are generated within a polygon
- Analysis – previously collected data can be used to compute sample size
requirements or efficiently allocate samples among strata - Computations –mean, standard error, confidence intervals for sample data
and inferences of population parameters with known certainty - Output – geographic positions in output simplifies migration to global
positioning systems, and sample size estimates and sample statistics can be
exported to text files for record keeping
Example of random sampling (from the manual):
Stumbled across this the other day, and while I don’t currently have the need for it (or a copy of ArcGIS to try it out on), it sounds useful enough to post about. NOAA’s Center for Coastal Monitoring and Assessment offers a free extension for ArcGIS called the Habitat Digitizer:
The Habitat Digitizer Extension is designed to use a hierarchical classification scheme to delineate habitats by visually interpreting georeferenced images such as aerial photographs, satellite images, and side scan sonar. The extension allows users to create custom classification schemes and rapidly delineate and attribute polygons, lines, and points using simple menus. The extension allows new hierarchical classification schemes to be easily created, modified, and saved for use on future mapping projects. There are several advantages to using classification schemes with a hierarchical structure including: the detail of habitat categories can be expanded or collapsed to suit user needs, the thematic accuracy of each category/hierarchical level can be determined, and additional categories can be easily added or deleted at any level of the scheme to suit user needs.
While written for habitat digitization, it could prove useful for any digitization projects with extensive classification requirements. Versions are available for ArcView 3.0, ArcGIS 9.0, and ArcGIS 9.2 from the product page; download files include a PDF manual.
ColorBrewer is an online Flash app designed to help select appropriate data coloring schemes for maps, including sequential (choropleths), diverging (data with break points), and qualitative (discrete categorical data). I’ve covered version 1.0 before, and now ColorBrewer 2.0 is out. Not a huge number of functional differences, but some useful additions (and one disappointing subtraction):
- More parameters are selected by drop-down boxes instead of buttons; bit faster this way
- All controls are on the left side, making them easier to find
- You can now choose between a colored background and a terrain background
- Color transparency can now be set between 0 and 100%
- More choices for background, road, city and border colors
- You can now screen color schemes by appropriateness for color blindness, photocopying and print. In version 1.0, you only had icons showing which uses were appropriate, and these are still available in the “Score Card” tab at lower right
- More options for color scheme export directly from the program, including an Excel file of all available color schemes, export in Adobe Swatch Exchange format (ASE), and in-program text hex color codes for copying and pasting into graphics programs.
- No more map zoom; I miss this option.
Here’s a screenshot of 2.0:
The National Cancer Institute has taken the ColorBrewer color ramps and incorporated them into ColorTool, a free plugin for ArcMap. From the website:
The program runs from a button in the toolbar and opens a form that guides the user in choosing a classification scheme…. ColorTool supports Quantile, Equal Interval, Natural Breaks (Jenks), and Unique Value classification types…. There are also legend options, area borders, and exclusion statements in the tool. ColorTool simplifies the display process by offering preset color schemes and eliminating incompatible options.
David Enns of MapItOut writes:
Subsequent to the development of low-cost tools by Map It Out in previous versions of ArcGIS Server, the company will now release these tools free of cost, starting with ArcGIS Server 9.3. It will be seeking input from users to develop other no cost tools. Map It Out Inc. hopes to offer several other ease-of-use and multi-functional tools at no cost in the upcoming months based on the input/demand from the GIS community.
The first available tools are:
- Area & Buffer Selection Tool
- Bookmark Tool
- Hyperlink Tool
- Export Tool
- Custom Query Tool
I don’t use ArcGIS Server, so can’t evaluate them; for anyone who does try them out, I’d welcome your opinions in the comments section.
mapz: a gis librarian has updated his ArcMap2GMap script for exporting ArcMap layers to a standalone Google Map page; in addition to points and lines, it now includes support for choropleth polygon layers:
Runs on ArcGIS 9.1 and 9.2, not yet tested on 9.3.
The Mapperz blog posts about ESRI’s new Models and Scripts Gallery, a resource for sharing and downloading geoprocessing models and scripts for ArcGIS 9.3. There are similar galleries available for .Net, Javascript and Java code:
- .Net ADF Code Gallery
- Java ADF Code Gallery
- ArcGIS JavaScript API Code Gallery
- ArcGIS JS Extension for Google Maps Code Gallery
- ArcGIS JS Extension for Virtual Earth Code Gallery
- ArcGIS Desktop Code Gallery
- Model and Script Tool Gallery
- ArcGIS .Net Engine Code Gallery
- ArcGIS Java Engine Code Gallery
And the old resource page for Arcscripts is still available as well.
