AERMAP Course #423 Day 2 Afternoon Air Pollution Dispersion Models: Applications with the AERMOD Modeling System AERMAP Course #423 Day 2 Afternoon

Day 2 Afternoon: AERMAP

Overview Purpose of AERMAP Data Products AERMAP Processes AERMAP Input Requirements Control File Structure and Options Data Running AERMAP and Reviewing Output Special Topics/Considerations

Learning Objectives At the end of this session, you will understand: Why AERMAP exists The data requirements and where to get them The structure of the control file How to run the AERMAP program How to interpret the results Some of the issues surrounding AERMAP

AERMAP - Purpose Develop terrain base elevations for every receptor and source Develop the hill height scale for every receptor Defined as the height that has the greatest influence on dispersion for a receptor. Independent of wind direction. Used by AERMOD to calculate the critical dividing streamline height Recall that AERMOD’s default mode is run with non-flat terrain (the FLAT model option is a non-regulatory option) Hill height scale: Defined as the height that has the greatest influence on dispersion for a receptor. Independent of wind direction. Used to calculate the critical dividing streamline height, which can be thought of as the level in the stable atmosphere where the flow has sufficient kinetic energy to overcome the stratification and rise to the height of the terrain. For each individual receptor, the hill height scale is the highest stored elevation within the AERMAP DOMAIN for which the slope between elevation at the receptor and the elevation data node is 10% or greater.

AERMAP – Data Products Data are available in three formats (standards) USGS “Blue Book” standard National Elevation Data (NED) Spatial Data Transfer Standard (SDTS) The three data formats are presented in subsequent slides.

AERMAP – Data Products USGS Digital Elevation Model (DEM) Data Data Standards “Blue Book” standard – ‘native’ format Spatial Data Transfer Standard (SDTS) – more recent format requiring converting to the ‘native’ format Data Resolution Commonly used in the past: 7.5 minute and 1-degree Other: 15-minute and 30-minute Status of DEM Data and Data Sources The USGS Data Users Guide 5 for DEM's (traditionally known as the "blue book"), last published in 1993. The format and discussion for this standard can be found in the AERMAP user’s manual. From the USGS web site for SDTS: “… a robust way of transferring earth-referenced spatial data between dissimilar computer systems with the potential for no information loss.” To use SDTS data in AERMAP you must first convert the SDTS data back to the ‘native’ DEM format using a routine specific for that purpose. One is available from the EPA’s SCRAM web site. Data Resolution Large scale 7.5-minute: 1:24,000 and 1:25,000 scale - 15-minute: 1:50,000 scale Intermediate scale 2 arc-second (30-minute): 1:100,000 scale Small scale 1-degree: 1:250,000 scale AERMAP can process a mix of DEM resolutions in a single AERMAP run. Units for elevations vary by resolution: 7.5-minute: For the continental U.S. are either meters, feet, decimeters (tens of meters), or decifeet (ten’s of feet) referenced to mean sea level 1-degree: Elevations are in meters relative to mean sea level

AERMAP – Data Products National Elevation Dataset (NED) What is NED High resolution elevation data available across the United States in a seamless raster format with a consistent datum, projection, and elevation units (meters) Format – GeoTIFF binary file that includes data descriptors and geo-referencing information in the form of “TiffTags” and “GeoKeys Data Resolution 1-arcsecond, 1/3-arcsecond, and 1/9-arcsecond 30-meters, 10-meters, and 3-meters (approximately) A key concept here is the seamless raster format. Only one file may be required for AERMAP, depending on the extent of the domain of interest, whereas AERMAP could require two or more DEM files to accomplish the same task, with the potential for different datums. “The GeoTIFF specification defines a set of Tagged Image File Format (TIFF) tags to describe all "Cartographic" information associated with TIFF imagery that originates from satellite imaging systems, scanned aerial photography, scanned maps, digital elevation models, or as a result of geographic analyses. Its aim is to allow means for tying a raster image to a known model space or map projection. “ (http://www.gisdevelopment.net/technology/ip/mi03117pf.htm) AERMAP supports processing multiple NED files in a single model run . AERMAP does NOT support processing both USGS DEM and GeoTIFF data formats within a single application. It uses a GeoKey (MetaTag) approach to encode information elements into a set of reserved TIFF tags to store a broad range of georeferencing information. AERMAP processes these TIFF Tags and GeoKeys to determine the type and structure of the elevation data within the NED file. NED elevation data are in a consistent reference datum and horizontal resolution. Use of NED data instead of DEM data has the advantage of avoiding potential issues associated with inconsistent datums within the domain. Data Resolution: Nationwide coverage is available for data at a 1 arc second (30 meter) post spacing; there also is substantial coverage at 1/3 arc second (10 meter) post spacing.

AERMAP – Data Products National Elevation Dataset (NED) – cont’d Data Sources and Availability Multi-Resolution Land Characteristics Consortium (MRLC) http://www.mrlc.gov/ 1- arcsecond, 1/3-arcsecond Must specify GeoTIFF format Shuttle Radar Topography Mission (SRTM) Data High-resolution digital topographic database Warning: SRTM data which can be found from various sources on the Internet represent the elevation of the tops of surfaces in most cases (e.g., buildings, thick tree canopies). Data Sources and Availability NED Data NED data in GeoTIFF format is available at no cost from the Multi-Resolution Land Characteristics Consortium (MRLC) website at the address listed. NED data are available in 1-arcsecond and 1/3-arcsecond resolutions. GeoTIFF may not be the default format for download, in which case you will need to be sure to specify GeoTIFF format. SRTM Data The Shuttle Radar Topography Mission (SRTM) obtained elevation data on a near-global scale to generate the most complete high-resolution digital topographic database of the earth. Version 2 is the ‘finished’ version. This data can be found in GeoTIFF format from various sources on the Internet. WARNING: SRTM data do not necessarily represent ground elevations - tops of surfaces such as thick tree canopies and buildings may be reported as the elevation, although the radar may have penetrated some distance into the canopy. For more information see http://www2.jpl.nasa.gov/srtm/faq.html.

AERMAP – Control File Same Pathway/Keyword Structure as in AERMOD, except there are fewer pathways CO, SO, RE, OU pathways Keywords – each pathway has its own unique set of keywords Record structure 2-character-pathway keyword secondary-keyword/parameters The pathways for AERMAP are as follows: CO: For specifying overall job COntrol options; SO: For specifying the SOurce location information (optional); RE: For specifying the REceptor information; and OU: For specifying the OUtput file information. The source pathway is optional. If a client has provided the terrain elevation, you may use it. However, differences between AERMAP-derived elevations and a client’s elevations can result differences in the output from AERMOD. Depending on the purpose of the modeling and how close the results are to any standards that the results are compared to, it is recommended to use AERMAP to confirm the elevations for any regulatory application. Keywords specify the type of option or input/output data and the parameters following the keyword define the specific options or actual file names. There are similarities and differences between the keywords in AERMAP and AERMOD. Most of the commonalities are on the receptor pathway.

AERMAP – Control Pathway * Indicates keyword is required CO STARTING * Indicates that the pathway keywords start with the next record CO TITLEONE * Provides a way to identify the model run in the output file(s) TITLEONE title1 CO RUNORNOT * Instructs AERMAP to run or only check the processing setup without running RUNORNOT RUN or NOT CONTROL Pathway STARTING Informs AERMOD that keywords to process for the pathway are to follow; there are no secondary keywords or parameters associated with this keyword TITLEONE title1 Title1: Adds identifying information to the output files; up to 68 alphanumeric characters – more characters can be entered, but only 68 are printed in the output RUNORNOT RUN or NOT Option to run AERMAP or perform a check on syntax and completeness of the entire control file; options are: RUN: Full model calculations NOT: Process setup data and report errors, but do not run full model calculations

AERMAP – Control Pathway CO DATATYPE * Specifies the type of the raw terrain data DATATYPE DEM (FILLGAPS) or DATATYPE NED CO DATAFILE * Specifies the file name(s) of the raw terrain data input file(s) DATAFILE demfile (CHECK) DATAFILE nedfile (TIFFDEBUG) (ElevUnits) CONTROL Pathway (cont’d) Note: Parentheses () around a secondary keyword or parameter indicates the keyword or parameter is optional. DATATYPE (non-repeatable) DEM: Specifies that Digital Elevation Model (DEM) data will be used (including 7.5-minute, 15-minute, and/or 1-degree DEM data) FILLGAPS: Option for AERMAP to calculate elevations for receptors (and/or sources) located within gap areas based on closest nodes for DEM data; gap receptor/source elevations will otherwise be assigned a missing code of -9999.0 OR NED: Specifies that National Elevation Dataset (NED) data in GeoTIFF format will be used DATAFILE demfile (CHECK) (repeatable) Demfile: Identifies the name of the DEM data file CHECK: Option to perform a check on the full DEM file DATAFILE nedfile (TIFFDEBUG) (ElevUnits]) (repeatable) Nedfile: Identifies the name of the DEM data file TIFFDEBUG: Option to generate a debug file with all the TiffTags and GeoKeys in the NED file ElevUnits: Option for user-specified elevation units accepts FEET, DECIFEET, DECIFEET, DECAFEET, DECA-FEET, METERS, DECIMETERS, DECIMETERS, DECAMETERS or DECA-METERS not case-sensitive The DATATYPE keyword is NOT repeatable; the DATAFILE keyword is repeatable You can specify more than one file, but all the files must be of the same type.

AERMAP – Control Pathway CO ANCHORXY * Relates the origin of the user-specified coordinate system for receptors to the UTM coordinate system ANCHORXY Xauser Yauser Xautm Yautm Zautm (NADA_value)* Xauser, Yauser: Location in the user’s coordinate system Xautm, Yautm: Location of the same point in the UTM coordinate system NADA_value: North American Datum Anchor point – the horizontal datum used to establish the anchor point and range from 0 to 6 (discussed later) (optional) CONTROL Pathway (cont’d) ANCHORXY: Relates the origin of the user-specified coordinate system for receptors to the UTM coordinate system Xauser: X coordinate of any geographic location (typically the origin 0,0) in the user coordinate system in meters Yauser: Y coordinate of any geographic location (typically the origin 0,0) in the user coordinate system in meters Xautm: UTM East coordinate of the same geographic location specified as Xauser,Yauser in meters Yautm: UTM Northing coordinate of the same geographic location specified as Xauser,Yauser in meters Zautm: UTM Zone of the same geographic location corresponding to Xautm, Yautm If local coordinates are used, (Zauser, Yauser) typically will be (0,0). If the coordinates for the receptors and sources are already in UTMs, then the coordinate pairs {(Xauser, Yauser) and (Xautm, Yautm)} are the same If local coordinates are specified , the coordinate pairs will be different NADA _value: The datum from which the Xautm, Yautm coordinates were drawn; an optional parameter with a default of 0. Xautm and Yautm are reference coordinates. If the NADA_value specified is different from the datum indicated within the elevation data files, a conversion may be performed so that the coordinates in the elevation files are consistent with the reference coordinates.

AERMAP – Control Pathway CO TITLETWO provides a second title line in the output file(s) TITLETWO title2 CO DOMAINLL Specifies the geographic extent, in lat/lon, of the search for the controlling terrain feature or hill height scale DOMAINLL Lonmin Latmin Lonmax Latmax Lonmin, Latmin specifies the southwest (lower left) corner of the extent; Lonmax, Latmax specifies the northeast (upper right) corner of the extent CONTROL Pathway (cont’d) TITLETWO: Provides a second title line in the output file(s). Title2: Adds identifying information to the output files; up to 68 alphanumeric characters – more characters can be entered, but only 68 are printed in the output AERMAP Domain One of two keywords can be used to specifiy a fixed domain in which to limit AERMAP’s search, geographically for elevations at source and receptor locations, as well as hill height scales. The domain can be entered using latitude and longitude in decimal degrees (DOMAINLL) or UTM coordinates in meters (DOMAINXY). If a domain is not specified, AERMAP will process the entire geographic extent represented in the NED or DEM files listed. Depending on the geographic coverage of the files, omitting a domain may slow processing significantly. While not specifying a domain should not affect elevations derived for source and receptor locations, it could affect the hill height scales. Remember, the hill height scale is the highest stored elevation within the AERMAP DOMAIN for which the slope between elevation at the receptor and the elevation data node is 10% or greater. The DOMAINLL and DOMAINXY keywords and parameters are shown here and on the next slide. DOMAINLL: Specifies AERMAP domain in decimal degrees latitude and longitude. Lonmin: Longitude in decimal degrees of the southwest (lower left) corner. Latmin: Latitude in decimal degrees of the southwest (lower left) corner. Lonmax: Longitude in decimal degrees of the northeast (upper right) corner. Latmax: Latitude in decimal degrees of the northeast (upper right) corner.

AERMAP – Control Pathway CO DOMAINXY Specifies the extent, in UTM coordinates, of the search for the controlling terrain feature or hill height scale DOMAINX Xdmin Ydmin Zonmin Xdmax Ydmax Zonmax Xdmin, Ydmin: Specifies the southwest (lower left) corner of the extent Zonmin: UTM zone for the lower left corner Xdmax, Ydmax: Specifies the northeast (upper right) corner of the extent Zonmax: UTM zone for the upper right corner CONTROL Pathway (cont’d) DOMAINXY: Specifies the extent, in UTM coordinates, of the search for the controlling terrain feature or hill height scale. Xdmin: UTM East coordinate, in meters, of the southwest (lower left) corner. Ydmin: UTM North coordinate, in meters, of the southwest (lower left) corner. Zonmin: UTM zone of the lower left – southwest – corner. Xdmax: UTM East coordinate, in meters, of the northeast (upper right) corner. Ydmax: UTM North coordinate, in meters, of the northeast (upper right) corner. Zonmax: UTM zone of the upper right – northeast – corner.

AERMAP – Control Pathway CO NADGRIDS Specifies the path for the folder containing the NADCON (*.las and *.los) grid shift files NADGRIDS NADGridPath Without this keyword, the default path is the local folder containing the AERMAP.INP file CO DEBUGOPT Specifies whether additional debug output files will be generated for receptors, sources, and/or hill heights DEBUGOPT HILL and/or RECEPTOR and/or SOURCE CONTROL Pathway (cont’d) NADGRIDS: Specifies the path for the folder containing the NADCON (*.las and *.los) grid shift files. NADGrid Path: The location of the folder containing the grid shift files . The path can be up to 200 characters. Use double quotes around the path if there are embedded spaces in the path. Path must include the trailing backslash (\) for Windows applications or forward slash (/) for Linux/UNIX applications. Due to differences in the method for defining datums as well as variations in distortion, the relationship between datums may not be definable at every location by a single mathematical equation. This is true for conversion of the NAD27 datum to a NAD83 datum. The National Geodetic Survey (NGS) program NADCON (North American Datum Conversion) utility was incorporated into AERMAP to calculate datum shifts. NADCON transforms coordinates between the North American Datum of 1927 (NAD 27) and the North American Datum of 1983 (NAD 83). Latitude shifts are in a file with the extension .las; longitude shifts are in a file the extension .los. NADCON grid shift files are only required when a NAD conversion is needed based on the user specified NADA and the reference datums among the input terrain files

AERMAP – Control Pathway CO TERRHGTS Controls whether the receptor elevations are extracted from the terrain data or that user-provided receptor elevations are used TERRHGTS EXTRACT or PROVIDED CO FLAGPOLE Specifies default value for height of flagpole receptors FLAGPOLE (Flgdflt) CO FINISHED * Indicates the pathway keywords have ended CONTROL Pathway (cont’d) TERRHGTS: Controls whether the receptor elevations are extracted from the terrain data or that user-provided receptor elevations are used EXTRACT: Determine the terrain heights from the DEM data files provided by the user (default). PROVIDED: Use the user-specified receptor elevations that are entered on the receptor pathway; also applies to source elevations specified on the optional source pathway. FLAGPOLE: Specifies default value for height of flagpole receptors. Flgdflt: Height above local ground level , in meters; if this keyword is omitted, then the default value is 0.0 meters FINISHED: Informs AERMOD that there are no more keywords for this pathway to be processed.

AERMAP – Source Pathway SO STARTING * Indicates that the pathway keywords start with the next record SO LOCATION Identifies source locations for use in extracting source elevations and/or to define the origin of discrete polar receptors LOCATION Srcid Srctyp Xs Ys (Zs) The LOCATION keyword and parameters may be stored in a separate file and referenced using the INCLUDED keyword and file name (discussed on the next slide). SOURCE Pathway STARTING: informs AERMOD that keywords to process for the pathway are to follow. LOCATION: Identifies source locations for use in extracting source elevations and/or to define the origin of discrete polar receptors. The LOCATION keyword and parameters may be stored in a separate file that gets referenced and incorporated into the control file using the INCLUDED keyword and filename. The INCLUDED keyword is discussed on the next slide. Srcid: Alphanumeric source ID, up to 12 characters Srctyp: Source type: POINT, VOLUME, AREA, AREAPOLY, AREACIRC, OPENPIT, POINTCAP, or POINTHOR Xs, Ys: X-coordinate (easting) and Y-coordinate (northing) of POINT sources (including POINTCAP and POINTHOR), the center of VOLUME sources, a corner for AREA and OPENPIT sources, and the first vertex for AREAPOLY and AREACIRC sources (in meters) Zs: Optional elevation above mean sea level (in meters) AERMAP ignores and SRCPARAM records that may be included as a result of copying and pasting from an existing AERMOD file.

AERMAP – Source Pathway SO INCLUDED Identifies an external file containing source locations to be included as input to AERMAP (optional) INCLUDED SrcIncFile If there are no LOCATION keyword records, the INCLUDED keyword should be present SO FINISHED * Indicates that there are no more pathway keywords to process (mandatory) SOURCE Pathway (cont’d) INCLUDED: Identifies an external file containing source locations to be included as input to AERMAP (optional) SrciIncFile: Identifies the filename for the included source file. Repeatable. Up to 200 characters in length. Double quotes (“) may be used as delimiters for the filename to allow for embedded spaces. Quotes, if used, do not count toward the limit of 200. If an error is generated during processing of an included file, the error message will report the line number of the included file If more than one INCLUDED file is specified for a particular pathway, you will first need to determine which file the error occurred in since AERMAP does not report which file the error occurred in FINISHED: Informs AERMOD that there are no more keywords for this pathway to be processed.

Receptor Pathway Keywords RE STARTING * Pathway keywords start with the next record RE ELEVUNIT Input units for receptor elevation (default: METERS) ELEVUNIT METERS or FEET Though optional, when ELEVUNIT is specified in the control file, it must be the first keyword following the STARTING keyword. RECEPTOR Pathway STARTING: Informs AERMOD that keywords for the receptor pathway are to follow; there are no parameters or secondary keywords associated with this primary keyword. Not repeatable. ELEVUNIT: Input units for receptor elevation (default: METERS) Valid parameters are ‘meters’ and ‘feet’ (without quotes). If it is used, it must be the first keyword after STARTING. Not case sensitive METERS, meters, FEET, or feet.

Receptor Pathway Keywords RE GRIDCART gridded locations referenced to a Cartesian coordinate system Netid STA XYINC Xinit Xnum Xdelta Yinit Ynum Ydelta or XPNTS Gridx1 Gridx2 Gridx3 .... GridxN, and YPNTS Gridy1 Gridy2 Gridy3 .... GridyN ELEV Row Zelev1 Zelev2 Zelev3 ... ZelevN FLAG Row Zflag1 Zflag2 Zflag3 ... ZflagN END RECEPTOR Pathway (cont’d) The following grid types will be presented: GRIDCART, GRIDPOLR, DISCCART, DISCPOLR, and EVALCART. At least one of these keywords must be present unless the INCLUDED keyword is used to include receptor inputs from an external file (the EVALCART keyword will not be discussed; more information can be found in the AERMOD user’s manual and addendum) Multiple Cartesian grids can be defined for a single model run, i.e., this record is repeatable. The specification of the gridded receptors requires secondary keywords and parameters to completely define the grid. GRIDCART: Gridded receptor locations referenced to a Cartesian coordinate system. Netid: Receptor network identifier (up to 8 characters) STA: Start the definition of the Cartesian grid (Notes continue on the next page.)

Receptor Pathway Keywords RE GRIDPOLR gridded locations referenced to a polar coordinate system Netid STA ORIG Xinit Yinit OR ORIG SrcID DIST Ring1 ... RingN DIR Dir1 … DirN OR GDIR Dirnum Dirini Dirinc ELEV Dir Zelev1 ... ZelevN FLAG Dir Zflag1 ... ZflagN END RECEPTOR Pathway (cont’d) Multiple polar grids can be defined for a single model run, i.e., this keyword is repeatable. The specification of the gridded receptors requires secondary keywords and parameters to completely define the grid. GRIDPOLR: Gridded receptor locations referenced to a polar coordinate system. Netid: Receptor network identifier (up to 8 characters). STA: Start the definition of the polar grid. There are two ways to define the grid origin ORIG: Optional keyword to specify the origin of the polar network (assumed to be at x=0, y=0 if omitted) Xinit: Origin of local x-coordinate (meters). Yinit: Origin of local y-coordinate (meters). OR SrcID: Source ID of source used as origin of polar network (up to 12 chars). DIST: Keyword to specify distances for the polar network. Ring1 … RingN: An array of distances to the rings of polar coordinates. (Notes continue on the next page.)

Receptor Pathway Keywords RE DISCCART discrete locations referenced to a Cartesian system DISCCART Xcoord Ycoord (Zelev) (Zflag) RE DISCPOLR discrete locations referenced to a polar network DISCPOLR Srcid Dist Direct (Zelev) (Zflag) RE INCLUDED include data from a separate file INCLUDED RecIncludeFile RE FINISHED * the pathway keywords have ended RECEPTOR Pathway (cont’d) DISCCART: Unlike the gridded Cartesian system, there is no ‘network’ identifier. The receptors are simply listed one after another with: Xcoord: Local x-coordinate for discrete receptor location (m). Ycoord: Local y-coordinate for discrete receptor location (m). (Zelev): Elevation above sea level (m) (optional) – used only with ELEV keyword on CO pathway. (Zflag): Receptor height (m) above local terrain (optional), used only with the FLAGPOLE keyword on the CO pathway. DISCPOLR: The discrete polar network is equally simple; note that the polar network is referenced to a particular source. Srcid: Source identifier for which the polar network is referenced, i.e., the origin of the polar network. Dist: Downwind distance to the receptor location (m). Direct: Direction to the receptor location (degrees from north, clockwise).

AERMAP – Output Pathway OU STARTING * pathway keywords start with the next record OU RECEPTOR * Identifies the output filename for the receptor data RECEPTOR Recfil OU SOURCLOC Identifies the output filename for the source data SOURCLOC Srcfil OU FINISHED * the pathway keywords have ended OUTPUT Pathway The output pathway identifies the various files that are or may be written. Only the receptor file is mandatory. This implies that even though only source elevations are needed, at least one receptor must be included in the AERMAP run. None of the keywords associated with the filenames is repeatable. STARTING: Informs AERMOD that keywords for the output pathway are to follow; there are no parameters or secondary keywords associated with this primary keyword RECEPTOR: Identifies the output filename for the receptor data. Recfil: Path and filename. The output filename can be up to 200 characters in length, up to a limit of 512 characters for the full input record; double quotes (“) may be used as delimiters for the filename to allow for embedded spaces; quotes don’t count toward the limit of 200. SOURCLOC: Identifies the output filename for the source location data. Srcfil: The same conditions for the receptor file also apply to the source file. FINISHED: Informs AERMOD that there are no more keywords for this pathway to be processed.

AERMAP – Output Pathway Recall the debug options on the CO pathway HILL, RECEPTOR, SOURCE Three debugging output files are available associated with these options DEBUGHIL HillDebug DEBUGREC RecDetail RecNDem RecElv DEBUGSRC SrcDetail SrcNDem SrcElv Debug output for hill height scale, receptors, and sources, respectively OUTPUT Pathway (cont’d) DEBUGHIL: Identifies the output filename for the optional hill height scales debug file. HillDebug: Path and filename. DEBUGREC: Receptor related debug information. RecDetail: Filename for the RecDetail debug file, which provides information on NAD conversions and domain check RecNDem: Specified filename for the RecNDem debug file, which provides information on the DEM/NED file assignment RecElv: Filename for the RecElv debug file, which provides information on the receptor elevation calculations DEBUGSRC: Source debug information. SrcDetail: Filename for the SrcDetail debug file, which provides information on NAD conversions and domain check SrcNDem: Specified filename for the SrcNDem debug file, which provides information on the DEM/NED file assignment SrcElv: Filename for the SrcElv debug file, which provides information on the receptor elevation calculations The same conditions that apply to the receptor and source output filenames also apply to the debug output filenames

AERMAP – Running AERMAP AERMAP expects the control file to be named AERMAP.INP Windows environment – double-click aermap.exe Command prompt environment – type ‘aermap’ (without quotes) and press return Running AERMAP Remember that a file named aermap.out is created. If you need to run AERMAP a second time and do not want to lose the .out file from the previous run, rename aermap.out before before rerunning AERMAP. The same is true of the names of files identified in the control file. Why would someone want to do this? Maybe to compare the effects of specifying more or fewer terrain files or maybe to see the effects of changing the extent of the domain.

AERMAP – Reviewing the Output AERMAP.OUT The standard output Echos control file Indicates whether the SETUP routines finished successfully or not, with a list of warnings and errors (if any) General information regarding the number of files and file type, the total number of receptors and sources, automatically generated and user-specified debug file names Summary of fatal, warning, and informational messages Reviewing the AERMAP Output The standard output file is similar to the one generated by AERMOD.

AERMAP – Reviewing the Output AERMAP program includes both automatic and optional (user-specified) debug output files Automatic debug files DOMDETAIL.OUT Generated only if DOMAINLL or DOMAINXY is used Information regarding the extent of the user specified modeling domain, including which DEM or NED file contains each corner of the domain MAPDETAIL.OUT Summary of information regarding each DEM or NED file based on the results of the DEMCHK or NEDCHK routines MAPPARAMS.OUT Summary of the parameters for each DEM or NED file Reviewing the AERMAP Output The following are several debug/QA files that AERMAP automatically outputs: DOMDETAIL.OUT: If neither DOMAINLL or DOMAINXY appears in the control file, then this file will not be created MAPDETAIL.OUT: For NED files, this file will contain additional details related to any error or warning messages generated in the processing the TiffTags or GeoKeys MAPPARAMS.OUT: Based on the contents of the header record (logical record type A) for DEM or the TiffTags and GeoKeys for NED data, and also documents the adjacency of the DEM or NED files within the application area

AERMAP – Reviewing the Output AERMAP output / AERMOD-ready input ** AERMAP - VERSION 11103 10/04/13 ** 16:02:48 ** APTI 423 Receptors ** ------------------ ** A total of 1 NED files were used ** A total of 15 receptors were processed ** No user-specifed DOMAIN; all available data used ** ANCHORXY XX3955.0 YY68385.0 XX3955.0 YY68385.0 17 4 ** Terrain heights were extracted by default RE ELEVUNIT METERS DISCCART 453440.00 4369992.00 1.06 1.06 DISCCART 453454.63 4369992.00 1.06 1.06 DISCCART 453469.26 4369992.00 1.06 1.06 DISCCART 453483.89 4369992.00 1.06 1.06 DISCCART 453498.52 4369992.00 1.06 1.06 DISCCART 453513.15 4369992.00 1.06 1.06 DISCCART 453527.78 4369992.00 1.06 1.06 DISCCART 453542.41 4369992.00 1.06 1.06 DISCCART 453557.04 4369992.00 1.06 1.06 DISCCART 453571.67 4369992.00 1.06 1.06 DISCCART 453586.30 4369992.00 1.06 1.06 DISCCART 453600.93 4369992.00 1.06 1.06 DISCCART 453615.56 4369992.00 1.06 1.06 DISCCART 453630.19 4369992.00 1.06 1.06 DISCCART 453644.82 4369992.00 1.06 1.06 AERMAP creates a file of receptor (and/or source) locations and terrain elevations associated with those locations. In addition the hill height scale is computed and included for each receptor. The coordinates associated with the anchor point are purposely obfuscated since these data are from an actual site. The file, including the header records or just the receptor information, could be either copied and pasted or included through the use of the INCLUDED keyword into an AERMOD input control file.

AERMAP – Some Special Considerations Domain considerations Horizontal datums, NADA flags, and NADCON Data gaps and edge receptors Coordinate systems (local vs. UTM) AERMAP Special Considerations Domain considerations: When defining the domain or when deciding whether to omit the domain definition and allow AERMAP to use the full extent of the elevation data files, it is important to be aware of any prominent topographical features. In rare situations involving prominent terrain features which would be selected as the hill height scale beyond a reasonable range of influence, the domain options can be used to exclude such features from the analysis. AERMAP runtime can also be optimized by limiting the domain and excluding portions of the terrain inputs that can reasonably be assumed to have no influence on hill height scales for the specified receptor network. Datums, NADA, and NADCON: A datum is the set of mathematical formulae and the related parameters used to describe the shape of our irregular earth. Geographic coordinate systems use a spheroid to calculate positions on the earth. The datum defines the position on the spheroid relative to the center of the earth. Many different datums have been developed over the years and have improved with the use of satellite mapping technology. AERMAP converts coordinates to account for differences in the reference datums between receptors (and sources) and Digital Elevation Model (DEM) terrain files. One component of the coordinate conversion process is the conversion of geographic coordinates (Latitude and Longitude) between the two reference datums. The conversion could result in a datum shift, i.e., a difference in coordinates between the two datums. AERMAP incorporates the North American Datum (NAD) CONversion (NADCON) program to perform the data shift, accounting not only for the datum shift, but also the shift due to the projection from geographic to UTM coordinates. AERMAP uses a parameter, NADA, to specify the horizontal datum that was used to establish the UTM coordinates of the anchor point. These will be presented and discussed in a later slide.

AERMAP – Control Pathway Valid values for NADA (as found on ANCHORXY) NADA Description No conversion between NAD 27 and NAD 83 for the DEM nodes, receptors, or sources, and for international use. 1 North American Datum of 1927 (based on Clarke 1866 ellipsoid); shift to NAD83 as needed 2 World Geodetic System of 1972 (based on WGS 72 ellipsoid); shift from WGS72 to NAD27, as needed 3 World Geodetic System of 1984 (“identical” to the GRS 80 ellipsoid); shift from WGS84 to NAD27, as needed 4 North American Datum of 1983 (based on WGS 80 ellipsoid); shift from NAD83 to NAD27 5 Old Hawaii Datum (based on Clarke 1866 ellipsoid but not NAD 27); shift from Old Hawaii Datum to NAD83 6 Puerto Rico/ Virgin Island Datum (based on Clarke 1866 ellipsoid); shift from Puerto Rico/ Virgin Is Datum to NAD83 The NADA parameter for the ANCHORXY keyword indicates the datum from which the UTM coordinates were drawn. In the descriptions of the NADA values, we see several different datums mentioned: NAD27, NAD83, WGS72, WGS84, GRS80. While there are some minor differences between the WGS72, WGS84, and NAD83 datums, as discussed in the AERMAP User’s Guide, these differences are considered inconsequential for AERMAP applications, and AERMAP treats WGS72, WGS84, and NAD83 datums as equivalent. The focus of datum conversion in AERMAP is on the conversion of NAD27 coordinates to NAD83, and vice versa.

Summary In this course, we covered the following topics: Purpose of AERMAP Data products AERMAP processes and considerations associated with those products (DEM and NED) AERMAP input requirements Control file structure and options Data Running AERMAP and the output generated Special topics/considerations