NCDC / Climate Atlas / Frequently Asked Questions
Climate Atlas of the Contiguous United States
Frequently Asked Questions
- When will the next version of the Climate Atlas be available?
- Does the new version of the Climate Atlas run in Windows 2000, Windows ME, and Windows XP?
- How can I order the Climate Atlas?
- Where did the Atlas data come from?
- Can I get the meteorological data used for the maps?
- Can I get the original gridded data used to make the maps?
- What Datum, Spheroid, and Projection were used in this Atlas?
- What is the nominal resolution of the data?
- What do the logos on the maps mean?
- What is PRISM?
- How do I use ArcExplorer?
- What are all those menu choices across the top of the ArcExplorer window?
- Why are some menu choices 'grayed out'?
- How do I use the zoom feature of ArcExplorer to focus on a local area?
- How can I adjust the theme list on the left so that I can see all of the text there?
- How can I navigate up and down the theme list?
- What do the map titles in the theme list tell me?
- What are the different color schemes used for different elements?
- Can I check as many of the theme boxes as I want?
- How can I activate a theme?
- Why are those letters "A, B, C, D, ... I" in the map legends?
- What are Climate Divisions?
- Why don't the county and climate division lines precisely line up with the state lines?
- How do I highlight a particular interval on the map?
- Why do some of the maps appear 'pockmarked' with one interval repeatedly embedded in another interval?
- How can I change the presentation of the maps?
- Can I save the changes I make to the presentation of the maps?
- Why do words sometimes overwrite one another in the title area of the map display screen?
- What if I can't see the "City Lights "or the "Vegetation Cover" maps?
- Why might my computer sometimes hang up when I choose to "View the Maps" for another element?
- What if I can no longer access the Atlas maps through the Atlas interface?
- What use is the "WWW" tab above the theme frame?
- Can I make the Atlas run in Windows 2000, or Windows ME, or Windows XP?
- Can I create PDF images of the Atlas maps?
- Can I buy individual PDF image files of the Atlas maps?
- Can I buy individual ESRI shape files of the Atlas maps?
- What if I discover a problem in the Atlas?
- What if my question is not addressed here?
A new version of the Climate Atlas of the United States (covering the Lower 48 States, Alaska, and Hawaii) is available for sale now from
NCDC's on-line store.
The new version of the Climate Atlas is supported in Windows 2000, and Windows XP, but not in Windows ME.
A new version, Climate Atlas of the United States (covering the Lower 48 States, Alaska, and Hawaii) is available for sale now from
NCDC's on-line store. The older version is no longer available.
All of the Atlas data except data for the Vegetation, City Lights, Hail, and Tornadoes maps came from NCDC's data holdings. See Data Documentation for a description of all data sets used and where they came from.
The data used for most maps is available on the Atlas CD. However, it is in "dbf" format. If you have access to data base management software that recognizes the "dbf" format, you can use it to access the map data. The dbf data files are located in the folder structure: "climatls\aeprojs\dbfshape\project\". That folder structure is off the root directory of your CD. And, if you installed the Atlas onto your computer's hard disk drive, it's also off the directory structure you provided for the Atlas to be installed into. Each element's data is in a dbf file listed in the element cross-reference table. For example, data for the element, "Fastest Mile of Wind" is in "climatls\aeprojs\dbfshape\project\wind60c.dbf ". CAUTION: If you alter any file (dbf's included) in its original directory structure in any way, you may cause problems for ArcExplorer. It may cause ArcExplorer to display that element's maps improperly or not at all. It's far better to copy the dbf file somewhere else before altering it.
Gridded data for most maps with the OCS (Oregon Climate Service) logo are available for purchase through The Climate Source. These are high-resolution, latitude/longitude grids with continuous values for each pixel. Grids are in ESRI ASCII GRID format, which is compatible with most major GIS packages.
Spheroid: Clark Ellipsoid of 1866;
Projection: Albers Equal-Area with Central Meridian = -96.0, Reference Latitude = +37.5, Standard Parallel 1 = +29.5, and Standard Parallel 2 = +45.5.
The nominal resolution of the data is 4 Km. As a result, there are instances where the map data appear over water bodies along lakeshores and coastlines.
PRISM is proprietary climate modeling software used to produce 348 maps for this Atlas.
For detailed information on how to use Arc Explorer, click on ArcExplorer's 'Help' menu choice. Also you may double-click on the ArcExplorer handbook, "Aebook.pdf", located in the root directory of your Atlas CD (or off the directory structure you provided when you installed the Atlas onto your computer's hard disk drive). You must have Adobe's Acrobat Reader software installed to use the handbook. Adobe's Acrobat Reader is free software; if your computer does not have it, you can get it at: www.adobe.com.
Across the top of the ArcExplorer window are some tool icons, which you may experiment with. If you rest your mouse cursor over a tool icon, a brief description of the tool's purpose will appear. For more detailed information, refer to How do I use ArcExplorer?, above.
Some menu choices will appear grayed out because no theme is 'active'. Once you activate a theme, several ArcExplorer menu choices become active - no longer grayed out.
The zoom feature is available as symbols (the magnifying glasses with a ‘+' (Zoom In) and ‘-‘ (Zoom Out) on the ArcExplorer toolbar above the theme list and map. You can zoom into a rectangular area of interest by selecting the point of the upper left corner and dragging the cursor to the desired size of the zoom box.
The metadata boxes in the theme list (e.g., counties, climate divisions, interstates, etc.) are particularly useful for zooming in on a local area. Please note, however, that the nominal resolution of the data is 4 km, which limits the efficacy of zooming in to the sub-county or closer levels. In fact, if you zoom in too closely, ArcExplorer may become unstable and close without warning.
You can adjust the width of the theme list by moving the cursor between the map and edge of the theme list frame. When the cursor appears as a vertical line with outward pointing horizontal arrows, hold down the left mouse button and drag the cursor to the right. The map will automatically readjust its size. Note that these adjustments are not savable; ArcExplorer will reopen to a default width for the theme list.
Use the hollow arrow and the solid arrow found either in the lower right or in the upper right of the theme list pane. The solid arrow goes directly to the bottom (or top) of the list. The hollow arrow moves more slowly, but still too fast on some computers. To slow it some, activate the lowest visible theme (or highest, depending on the direction you want to go) and click on the hollow arrow once. That should limit the travel such that the active theme remains in view. Repeat as necessary to navigate up and down the theme list as far as you want.
The map title provides information on the time period, element description, and units of the map. The time period is denoted with a number (01-12 for months January through December and 13 for Annual) or a description; the element description is an abbreviated version of the title inscribed on the map; the units of the map, in almost all cases, is given parenthetically.
There are separate color schemes used for varying groups of elements. The colors were selected based on general conventions for some element groups, ease of reading, and lack of conflict with metadata colors (e.g., for counties, lakes, etc.) ArcExplorer supports the customization of these colors (see ArcExplorer documentation). The default colors are grouped as follows (with colors listed from low to high values):
Temperature: White, Pink, Purple, Blue, Green, Yellow, Orange, Red-Orange, Red
Precipitation: Rust, Orange, Light Orange, Yellow-Green, Light Green, Green, Blue-Green, Dark Blue-Green, Blue
Snow and Freezing Precipitation: Tan, Light Green, Light Blue, Blue, Blue-Gray, Purple-Gray, Purple, Gray, White
Pressure: Red, Light Red, Pink, White, Light Blue, Blue, Dark Blue, Blue-Black
Thunderstorms, Hail, and Wind: White, Light Gray, Dark Gray, Light Blue, Blue-Green, Yellow, Dark Yellow, Rust, Red
Fog, Sky Cover, and Visibility: Blue, Light Blue, Yellow, Light Yellow, White, Light Gray, Gray, Dark Gray, Burgundy
Sunshine: Burgundy, Rust, Red, Red-Orange, Dark Orange, Orange, Tan, Yellow, Pink
Yes. But ArcExplorer draws themes in order, from the bottom of the theme list to the top. So, you can see only the uppermost map theme whose check box is checked. Themes listed above the map themes, such as States, Climatic Divisions, etc., will draw atop the map themes.
You can activate a theme by clicking once on it. Once you activate a theme, several ArcExplorer menu choices become active too. (If you double click on a theme, you will bring up the theme properties dialog, which has many features. Refer to How do I use ArcExplorer?, above for further information on the theme properties dialog.)
ArcExplorer presents the intervals in the map legends in machine collating sequence order. The letters cause ArcExplorer to present the intervals in the order given.
Climate divisions represent regions within a state that are, as nearly as possible, climatically homogeneous. However some areas may experience rather extreme variations within a division (for example, the Rocky Mountain states). The divisions have been established to satisfy researchers in hydrology, agriculture, energy supply, etc., who require data averaged over an area of a state rather than for a point (station). Note that climate divisions are not the same as National Weather Service forecast zones.
The state boundaries are from a more resolute data source. The county and climate division lines are properly georeferenced, but are less resolute in order to speed up their access.
One quick and easy way to identify a specific interval (e.g., Mean Heavy Fog Days between 5.5 and 7.4) is to click on the color box left of the interval label in the theme list. The area covered by this interval will appear in yellow with black outlines, and a yellow box showing the interval selected will be shown in the lower left hand corner of the map. To deselect, click on the clear selection symbol (eraser symbol, second from right) above the map. The map must be 'active' in the theme list (i.e., a box appears around the legend information) in order to deselect.
The Climate Atlas methodology was based on spatial averaging using neighboring stations. Some stations with large differences from their neighbors (e.g., a mountaintop station, etc.) can exert an influence on their neighbors in this averaging process, resulting in 'pockmark' or 'bulls-eye' effects on some maps.
You can turn on and off any of the themes by checking or un-checking the box beside the theme name. You can reorder the themes in the list by right-clicking on the theme name and selecting "Move Theme" and choosing an action from the list provided.
You can save changes and see those changes the next time you view the element's maps.
When you close the ArcExplorer window it will ask you if you want to save the changes you made. If you answer 'yes', it will allow you to specify the path and file name under which you want to save the changes. (If you change the file name, the Atlas interface will not be able to open the renamed file for you. To open a renamed file, you'll have to invoke ArcExplorer directly and tell it where the file is and what its name is - method 1 below.) If you specify only a new path and retain the same file name, you can access the changed file in two ways.
1) You can bypass the Atlas interface by invoking ArcExplorer directly, from its desktop icon for instance. Once ArcExplorer is running, direct it to "Open Project". When the "Open ArcExplorer Project" dialog appears, specify the path and file name of the file that contains your changed maps. ArcExplorer will present the maps as they were when you saved them. This method allows you to continue using the Atlas interface to access the regular, unchanged, files without having to change the Data Location (method 2 below).
2) The alternative to invoking ArcExplorer directly is to click the "ClimateAtlas" menu item in the Atlas interface. Under that you will see "Data Location". Click on the "Data Location" menu item. In the dialog box that appears, enter the drive letter, a colon, and the path to your changed file. Do not add a slash at the end. Click the "Apply" button and then the "Close" button. Then you should be able to access the changed file(s). Note that this method will redirect the Atlas interface to open files only in the same path as you specified for your changed file. The "regular" Atlas files will be unreachable through the Atlas interface until you reset the Data Location to the path you specified at installation time.
That happens if you have more than one map theme's box checked - say, November, August and March. ArcExplorer draws the themes in order from the bottom of the theme list to the top. You can see only the uppermost map (March) no matter how many below March (November and August) you have checked. Yet, each map has text that is drawn too. So, even though you can see only one of the (several) maps that are drawn, you can see the text that is drawn for each. And since all maps' text draws in the same area, they will overwrite each other in upward succession.
Most likely, it's because your computer does not have Adobe's Acrobat Reader software installed. It's free software; if your computer does not have it, you can get it at: www.adobe.com.
If you are using the Atlas interface to call up the maps, you must close each ArcExplorer instance (window) before you ask for another map. Each open instance of ArcExplorer requires memory of your computer. After a certain number of instances there will not be enough free memory left for another instance, and it will hang up. So if you are using the Atlas interface to call up the maps, close ArcExplorer before you ask for a new element.
Probably the reason is that the "c:\ClimateAtlas_00\ClimateAtlas.cfg" file has been deleted, moved, or renamed. You can restore it by clicking the "ClimateAtlas" menu item in the interface. Under that you will see "Data Location". Click on the "Data Location" menu item.
In the dialog box that appears, enter either a) the drive letter of your CD-ROM drive and a colon, like: "D:" (if you did not install the Atlas onto your computer's hard disk drive), or b) the drive letter, a colon, and the directory structure you provided when you installed the Atlas onto the hard disk drive. In either case, do not add a slash at the end.
Click the "Apply' button and then the 'Close' button. Then you should be able to access the maps again.
It has no use in this Atlas application, but click on it anyway. It leads to an interesting ArcExplorer-enabled WWW site.
At NCDC we have installed the Atlas successfully onto a Windows 2000 pc. (We haven't tried it in Windows ME or Windows XP.) Here's how we made it work in Windows 2000:
1) Please note that neither NCDC nor ESRI supports ArcExplorer in Windows 2000, or Windows ME, or Windows XP. Please read the Atlas' Minimum Requirements page.
2) Download Sun's jre 1.3.1 for Microsoft Windows from the sun website. We got it from http://java.sun.com/j2se/1.3/jre/download-windows.html though we do not claim it's still available from that address. (If sun has superceeded jre 1.3.1 with a newer version, and jre 1.3.1 is no longer available, download the newer version; it will probably work as well.)
3) Double clilck on the downloaded file to install the jre 1.3.1. (We accepted the default directory structure the executable suggested, though that may not be critical.)
When we tried again to run the Atlas, it ran without a problem.
Outside NCDC, at least one customer has successfully installed and run the Atlas in Windows 2000. His solution, copied directly from his email to NCDC regarding the topic, is in italics immediately below.
I did get the Climate Atlas to work on our windows 2000 systems. What I did, and this may help other windows 2000 users, is that I had to be logged into the PC using administrator rights (for network users of course) and then went through the procedure and it worked fine. Also, it seems also that if you have gone in and installed the software and it does not work (like my problem yesterday), you can later log in and install the ArcExplorer software and it will work then using the aeclient.exe package on the CD. The problem I found is that to install the arcexplorer part of the package, you need to be logged in as a system administrator, which is part of the windows 2000 package. We got it to work, and are very happy with the product.
Regardless, neither NCDC nor ESRI supports ArcExplorer in Windows 2000. Please read the Atlas' Minimum Requirements page.
If you have Adobe Acrobat installed, you can create a PDF file of any Atlas map from ArcExplorer. Press the print button located near the top of the ArcExplorer interface and select "Acrobat PDFWriter" as the printer. Then specify where to save the output file.
But NOTE: Often ArcExplorer will not render the colors truly. The PDF's legend colors may not match the PDF's map colors.
Yes, individual ESRI shape files of each of the Atlas maps (excepting wind speed and direction) are available for purchase from NCDC's online store. But please note: the individual shape files are unprojected; they are in geographic coordinates. This is in contrast to the shape files on the Atlas CD, which are projected.
Downloaded Tuesday, 21-May-2013 06:50:34 EDT
Last Updated Wednesday, 20-Aug-2008 12:59:18 EDT by email@example.com
Please see the NCDC Contact Page if you have questions or comments.