Double Query Instructions
The double query form is appropriate for comparing or overlaying 2 different simple queries.
The 2 simple queries may differ in terms of the database, the time frame, the fish species,
the pathogens or any combination of these factors.
The results of both queries are displayed together, but kept differentiated.
Caution should be used when combining data from the Wild Fish Health Survey and the Historical Database.
See the limitations page for more information.
The double query may also be used to produce maps which allow a database search
for any location with a variable radius.
Normally the search radius is exactly the size of the dot on the map.
If a variable search radius is desired, simply enter "dummy" parameters for the first search
that will produce no results.
For example, using January 1, 1981 for the beginning and ending dates is certain to produce no results,
regardless of what fish and pathogens are selected.
But remember you must select at least 1 fish species and 1 pathogen anyway.
You may then select any search radius between 1 and 200 km from the 27 options provided and
complete the rest of second query form as desired.
See also the
data limitations page which contains a glossary of many of the terms used here.
Topics
There are 5 parameters specified twice each for a double query of the National Wild Fish Health Database.
All of these, except for the fish species and the pathogens have default values.
- Beginning Date:
All data collected before this date will be ignored.
The default is the earliest date in the database.
Invalid dates are converted to a valid date
(for example, February 31 becomes March 3 in a non-leap year).
- Ending Date:
All data collected after this date will be ignored.
The default is the end of the latest year in the database.
Invalid dates are converted to a valid date
(for example, February 31 becomes March 3 on a non-leap year).
- Available Databases:
There are currently 2 databases available, the National Wild Fish Health Survey
and the historical data compilation done at Colorado State University.
The default is for the National Wild Fish Health Survey.
- Fish Species:
Any number of fish species may be selected.
There is no default.
Selecting a family name takes all species in that family.
Only fish species that are actually present in the selected database will appear in the output.
An error is reported for failing to select at least 1 fish species
that is present in the selected database.
- Pathogen Species:
Any number of pathogens may be selected.
There is no default.
Only pathogens that are actually present in the selected database will appear in the output.
An error is reported for failing to select at least 1 pathogen that is present in the selected database.
Selecting more than 1 pathogen will frequently complicate interpretation as the same
individual fish become involved in multiple tests.
Because of this, confidence limits are given only for searches on a single pathogen.
There is 1 parameter (the search radius) that is unique to the second query.
This is the size of the circle on maps as well as the size of the search radius for location searches.
Note that maps with a large radius are more time consuming to produce.
There are 27 options provided between 1 and 200 km.
Note that the actual size of the circle on a map depends on its specified size and on the scale of the map.
It is possible for the circles to be smaller than the dots, which is not desirable.
As always, trial and error will quickly solve this problem.
There are also 3 graphics parameters that are common to both queries.
- Mapping Background:
There are 2 options, shaded relief maps or flat (solid colored) maps.
The default is "shaded relief".
There is no difference in computer run time.
- Color Scheme:
There are 2 choices for the basic color scheme for the maps. The default is "color slide".
Because of the greater depth of the data displayed in the double query,
the gray-scale option is not possible.
- Color Slide- Black background with colored symbols and circles
- Color Printer- White background with colored symbols and circles
Any of the maps may be saved and altered for specific needs.
For example, most graphics programs allow easy changes of color and
replacement of color with various fill designs.
- Plot Surrounding Points:
There are 2 options, yes or no. The default is yes.
When "no" is selected, points located outside the selected map area
(state or hydrologic unit) are not shown.
This feature will clip points exactly at the edge of the mapped area.
This applies only to the points of the first query.
The circles of the second query are always clipped exactly at the edge of the mapped area.
A query begins when the "submit" button is selected.
Each query is uniquely numbered for reference.
This "query number", along with the date, appears on all output and
it serves to link the output back to the query parameters.
The first page returned for each query lists the important query parameters
for verification and future reference.
This page should be saved if needed to interpret other output.
An error can occur only by failing to select a positive time span,
1 or more fish species, and 1 or more pathogens.
This must be done for both queries, even if only the second query results are desired.
If an error is reported, use the "back" button of the browser and fix the problem.
The maps for the double query are accessed directly from the bottom of the
initial query parameters verification page.
Maps for the 50 states, the 18 HUC regions and 2 versions of the conterminous USA
may be selected by name directly from the lists provided.
These maps display the pathogen status for both queries as colored dots and circles.
They also allow a database search for any location.
Depending on the search criteria, there may be many samples for a single location.
The most positive result is always displayed (red covers yellow, which covers green).
Points always cover circles.
For the double queries the database search results are arranged into 2 tables.
The first table is for the point display.
Here the search radius is the size of the dot, which varies depending on the scale of the map.
The second table is for the circle display.
Here the search radius is the one that was specified on the query form.
Only locations with dots will have data available that
meet the search criteria for the first query.
Only locations within the circles will have data available that
meet the search criteria for the second query.
Each search radius is reported above the appropriate search results table.
Once a location is selected there are options to get the Graphical Locater information,
to go to the HUC Selection Table, or to make a custom map.
On these tables, the full case details may be obtained by selecting the case number.
A statistical report for the current query is also available for each case by selecting the "stats" link.
On the case details, the position data may be further reviewed by selecting
"Graphical Locater Information".
The HUC Selection Table allows accessing information for 6 HUC-defined areas:
- The selected cataloging unit
- The accounting unit
- The subregion
- The region
- The upstream cataloging units
- The downstream cataloging units
Further kinds of information and maps for each HUC-defined area
are available by selecting the area name.
Other options allow for dot maps, and for database search tables, by HUC-defined area,
as HTML, text or summaries only.
Dot maps are not available for accounting units that do not differ from the subregion.
The selected circle size must be appropriate to the scale of the selected map.
For example, 20 km is small on the USA map, but large on HUC cataloging unit maps.
The circle size does not affect HUC-defined database searches.
The sample must be in the HUC in order to be included.
The information page and dot maps for upstream cataloging units and
downstream cataloging units are the same.
The database search tables will be different.
The upstream/downstream dot map do not include the circle displays, but the other dot maps do.
The options that follow on each of these paths are the same as described above.
Begin a double query now.
11 JUNE 2001, Last Updated 4 APR 2002
dlg@rapid.msu.montana.edu