ArcGIS Explorer Blog : Symbols

Alternate Explorer symbols

ArcGIS-Explorer-Team — Fri, 17 Oct 2008 19:56:00 GMT

Today we found ourselves in search of a symbol for a project we were working on. While Explorer has lots to choose from, none of them were exactly what we wanted. So we began a search for symbols on the Web, with the requirement being that the symbol must be in the public domain and free to use. Our search turned up several choices on Wikimedia Commons. That's a place we sometimes forget to check, but is a valuable resource for icons, symbols, pictures, and a variety of other media. Let's go through the steps.

Here's our result, with the default red pushpin:

First we searched Wikimedia Commons to find a symbol we liked. Here's one we found:

We checked the copyright information to make sure it was not copyrighted and in the public domain, and therefore ok for us to use in our project - it was. To add the image to our symbol library, we clicked on the image and copied the URL at the top of the page:

Then we right-clicked the red pushpin in Explorer and opened its properties, and chose symbol properties. We clicked Add a Symbol... and pasted the URL into the Filename input:

This placed the png into our symbol library, and automatically sized it. Here's our new symbol in Explorer:

Tip: Creating polygon results from the measure task

ArcGIS-Explorer-Team — Thu, 16 Oct 2008 18:01:00 GMT

This morning we had an interesting question concerning a result created from the measure task. In this case the user was measuring the area of building rooftops, and wanted to create a result using that area.

To measure area, just activate the measure task, choose the polygon tool, and digitize around the outline of the rooftop. The area measurements can be displayed in a variety of different units. Here we've digtized around the roof edge of a warehouse, and have come up with a figure of about 18,478 square feet.

One of the measure options allows you to create a result from the measurement (the Create Result button you see on the task). When the result was created from the area measurement above, the complaint from the user was that it "looked wonky." We agreed. The result looked something like that below:

The reason it looked "wonky" is that the default symbol uses an outlined polygon. For a measure result we can't control the symbol size of the outline (an oversight that we'll fix in the next release). But the easy workaround is to choose a non-outlined symbol by opening the result property sheet, like the one shown below:

When Lightning Strikes

ArcGIS-Explorer-Team — Fri, 11 Jul 2008 15:34:00 GMT

California has already had another bad fire year with many hundreds of fires burning throughout the state, most started by lightning. Between June 21 and June 22 there were nearly 10,000 strikes (9,927 to be exact). Here's an Explorer view of the strikes during that period.

So how did we do this? Let's take a closer look...

How was the lightning strike information captured? Vaisala is company specializing in a variety of real-time detection systems and services, and has established the National Lightning Detection Network (NLDN). This nationwide sensor-based detection system tracks cloud-to-ground lightning activity across the continental US, 24 hours a day, 365 days a year. While the Bureau of Land Management once had their own detection grid, the BLM now contracts out to Vaisala, using their detection grid.

The Automated Lightning Mapping System (ALMS) extension for ArcGIS was used to download the near real time strike location information from the BLM data server. Using the extension strike information can be chosen for a particular time frame and geographic extent. The data was download via the internet in shapefile format.

In Explorer we chose File > Open > Shapefiles to add the shapefile data to our map. We wanted to symbolize the lightning strikes using our own lightning symbol. We made one using Photoshop, starting by creating a new image with square dimensions (we chose 30 pixels a side) and making sure our background was transparent. We drew our lightning bolt, then saved it as a local PNG file.

The next step was to use our new symbol for the lightning strikes. Here we've opened the Select Symbol window.

But rather than choosing one of the existing symbols, we clicked Add a Symbol and navigated to the folder that we saved our PNG from above in, and selected our custom symbol instead.

The ESRI Wildfire Management site has more information on using GIS for wildfire management, prevention, and suppression. Also see the Adding a new symbol Explorer Help topic.

(Thanks to Tom Patterson, ESRI Wildland Fire Specialist, for providing information and data)

Explorer at the PUG

ArcGIS-Explorer-Team — Sat, 01 Mar 2008 21:30:00 GMT

Earlier this week we posted on the Explorer presentation during the plenary at the Federal User Conference.

Here's an overview of the Explorer presentation during the plenary at the Petroleum User Group meeting (PUG), held in Houston last week.

The first part of the presentation was similar to the FedUC demonstration, showing how the default ArcGIS Online maps and a wide variety of other content services, including ArcIMS, ArcGIS Server map and globe services, and WMS services, could easily be accessed and integrated into a common map.

For the next section, Alaska was used as the study area to showcase the ability to add a variety of local data. Shown below are:

a raster (BSQ image) downloaded from the EROS site
a file geodatabase of the ANWR and Area 1002 boundaries
a shapefile with airport locations
a KML file showing soil chemistry downloaded from the USGS Minerals Resource site

Next, Area 1002 was visited, showcasing some of the new symbols available in Explorer (the camera symbols in this case). These notes were linked to popups showing Quicktime panoramas taken by USGS field crews.

The next section highlighted Explorer's capabilities for integrating a wide variety of non-map content based on location. In this case some of the wildcat wells studied by the USGS were shown, with each popup linking to a wide variety of online information published for each well. For example, links could be followed to view the photos of core samples taken at varying depths in each well, and other information such as depths to stratigraphic horizons, gamma ray data, and drilling and geologic reports.

Finally, the demonstration moved to the Gulf of Mexico where several custom tasks were used. Shown below are the fields in play in the Gulf region (the colored splotches indicate varying degrees of oil and natural gas yields) and the outlines of the oil leases in the Gulf (from a geodatabase obtained from the Minerals Management Service).

Leases were selected belonging to a particular oil company (the orange highlighted fields), and all adjacent leases expiring within 90 days were found (the red highlighted fields). This was accomplished using a geoprocessing task authored using ArcGIS Desktop, and published as a task for Explorer via ArcGIS Server.

The expiring leases were then sent to another custom task (by right clicking the result and using Send To) which generated a report for the selected leases, summarizing ownership, the terms of the lease, area, and other information.

Happy Holidays from the Explorer Team!

ArcGIS-Explorer-Team — Fri, 21 Dec 2007 21:00:00 GMT

We'd like to send you our Season's Greetings in the form of a screenshot showing a snowy Yosemite landscape via a live Web cam from Explorer (which, by the way, is using one of the new symbols included in this latest release, and the new Display Overlay capabilities to show the Season's Greetings message on the map.)

We'll be taking just a day or two off for the holidays, and would like to pause for a moment to thank everyone for helping make it such a great year for ArcGIS Explorer.

Season's Greetings!

- the ArcGIS Explorer Team

A Quick Peek at the Next Release

ArcGIS-Explorer-Team — Fri, 14 Dec 2007 17:04:00 GMT

We've been a little quiet here on the blog for the last couple of weeks. The reason? We've had our heads down working on the next release, which we're hoping to deliver very soon.

Here's a quick peek at a few of the new point symbols that will be included with this new version. In addition to the ones we'll provide, you'll be able to add your own custom symbols by choosing .jpg, .bmp, or .png files from your local drives or network, or from the Web.