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Displaying Maps <br />The CRDSS Spatial Database and the CU Model can display raster, vector, site, and/or paint-label maps developed <br />in Arc/Info and converted to GRASS. Multiple maps can be easily selected for display and map tools such as <br />legends, interactive covertype displays, scale-grid overlays, a map scale indicator, and an area locator map can be <br />used for map analysis. <br />Zooming and Selecting Areas for Display and Modeling <br />The VDB Interface and the CU Model can zoom into rectangular areas of the larger map. In addition to this feature, <br />the scale of the maps is updated, the resolution can be reset, the scale grid is accurately redisplayed, and the area <br />locator map is updated. The VDB Interface and the CU Model have the capability of selecting areas by township and <br />range. The user can enter the specifications of an area manually or select it from the maps displayed in the Main <br />Display Window. <br />Retrieving Information and Histories for Spatial Database Development <br />An extensive amount of documentation has been developed and is available with both the Arc/Info coverages used <br />for data development and the GRASS coverages used for display and modeling in the VDB Interface and the CU <br />Model. <br />The Arc/Info coverage files include ?README? text files in the directories where they are located (i.e. <br />/crdss/gis/arc/crdss_arc/). The files include a copy of the Arc/Info describe command output for each file, a general <br />description of the coverage, and a history of the source and development of the coverage. <br />The GRASS coverage Information is available through the Show Title Block option in the VDB Interface and the <br />CU Model (for more information see the CRDSS Users? Manual). The title block for each coverage contains a <br />detailed description of the coverage including specifications such as resolution and the Arc/Info source file used to <br />create the GRASS coverage (For information on this process see Task Memorandum 2.03-02: Conversion from <br />Arc/Info Coverages to GRASS). The title block for each coverage also contains a history of the development <br />including the original source and data development done for CRDSS. <br />Accessing the CRDSS Informix Database <br />CRDSS offers two ways to query information in the Informix database. The world wide web pages written in HTML <br />(HyperText Markup Language) and available through Mosaic or other browsers (see the CRDSS Users? Manual: <br />Supporting Software for more details). The second method is through the VDB Interface or the CU Model by <br />selecting sites from a site map from the CRDSS Spatial Database displayed in one of the interfaces. <br />The CRDSS Spatial Database capabilities include actual Internet queries of the CRDSS Informix database and the <br />ability to display graphs and retrieve data for modeling. Multiple sites from single maps with selections for data <br />types such as daily records, and specific periods in years or averages can be chosen for queries (i.e. one or more <br />sites, type of data such as daily or monthly records, and a period of years or average). A graph of the site data is <br />displayed using Xmgr (see the CRDSS Users? Manual: Supporting Software for more details) and the data can be <br />saved in a file or used in the CU Model. <br />The process of selecting sites for Informix data queries is to display a site map for the datatype desired, select and <br />area to be considered, select the sites on the screen using the mouse, and finally specifying the query type with years <br />or an average (for specifics see the CRDSS Users? Manual). <br />Page 5 <br />01/03/97 2.03- <br />01- Lange <br />