Climate Atlas of the Contiguous United States
Frequently Asked Questions
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 old version of the Climate Atlas of the Contiguous United States is still available for sale (while supplies last) at a reduced price of $50 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.
The Climate Atlas of the Contiguous United States is available for sale from NCDC's on-line store.
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.
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.
The NOAA logo is the logo of the National Oceanic and Atmospheric Administration (NOAA), a part of the U.S. Department of Commerce. This logo appears on all maps.
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.
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):
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.
Why do some of the maps appear 'pockmarked' with one interval repeatedly embedded in another interval?
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.
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.
It has no use in this Atlas application, but click on it anyway. It leads to an interesting ArcExplorer-enabled WWW site.
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.
Yes, individual PDF image files of each of the Atlas maps are available for purchase from NCDC's online store.
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.
If an element's titles appear crowded or overlapping or truncated on the map, maximize the map's window. That should eliminate any of those problems.
Click on the column title, "Field", above the field names. That will arrange the fields into alphabetic order.
The Elevation theme is not a climatic theme itself, but it is presented for interest and because of elevation's effects on many climate variables.
Some maps show more stations because of quality control issues. If a station's mean monthly data failed QC, it does not appear as a station on that month's map.
To uninstall the Atlas: 1) uninstall ArcExplorer 2.0 (from the Control Panel), 2) delete the directory "c:\Program Files\ClimateAtlas_02" (or whatever
directory you installed the Atlas files into), and 3) Delete the icons from your Desktop and Start Menu (right-click on each and select "Delete" from the subsequent menu).
If you discover a problem in the Atlas please notify NCDC via email.
You may email your questions to firstname.lastname@example.org.