Latest Contributions by ChrisSnyder

Python is kinda weird with division, and will return an integer anytime all the inputs are integer (example: 3/2 = 1). The trick is to just force one of the variables to be a decimal (aka float). (example: 3/float(2) = 1.5). Try this: gp.calculatefield_management ("highway", "minutes", "!length_mile!*float(60)/!minutes!","PYTHON") ... View more

Maybe a cursor would be faster - that is cursor through the .mdb file and build a shapefile that way? Seems like your .mdb file is on a network... Could it be that the network is slow? I would try to 1st copy the .mdb file locally, and then make the XYEventLayer. ... View more

To be ESRI-compliant, you should really use pgdbList = gp.listworkspaces("","ACCESS") and fgdbList = gp.listworkspaces("","FILEGDB") as part of the os.walk command, but how about this: import os rootDir = r"D:\csny490" gdbList = [] mdbList = [] for dirPath, dirNames, fileNames in os.walk(rootDir, topdown=True):    if dirPath.endswith(".gdb") or ".gdb." in dirPath:       gdbList.append(dirPath)    for file in fileNames:       if file.endswith(".mdb"):          mdbList.append(dirPath + "\\" + file) ... View more

This may get you part way there: http://arcscripts.esri.com/details.asp?dbid=16700 ... View more

Try naming your shapefile something else than a number (1.shp). Generally it is a bad idea to name a layer or field with a number as the 1st character. ... View more

For the addition to work (or pretty much any other raster math), your rasters must have the same spatial extent. So basically (I assume these are the light poles) for each raster you need to create a new raster where the NoData within your study area is 0 (or some other non NoData value). Here's some Python code that might give you some ideas: # Name: make_fast_mosaic_v93.py # # Description # ----------- # This script will mosaic a bunch of grids, but using a secret method that is # mucho faster than the standard v9.3.1 SP1 mosaic tool. # # Written By: Chris Snyder, WA DNR, 03/01/2010, chris.snyder(at)wadnr.gov # # Written For: Python 2.5.1 and ArcGIS v9.3.1 SP1 # # UPDATES: # # Notes on input parameters (for the toolbox): # VARIABLE             PAREMETER_INDEX     PARAMETER_DATA_TYPE # ------------------------------------------------------------------- # gridList             0                   Grids # outputGrid           1                   Grid # tempWorkspace        2                   Workspace # mosaicMethod         3                   String (MAX, MIN, or MEAN) # tempNoDataValue      4                   Long Integer try:     #Process: Import some modules     import os, string, sys, time, traceback, arcgisscripting     #Process: Create the gp object     gp = arcgisscripting.create(9.3)     #Process: Defines some functions used for getting messages from the gp and python     def showGpMessage():         gp.AddMessage(gp.GetMessages())         print >> open(logFile, 'a'), gp.GetMessages()         print gp.GetMessages()     def showGpWarning():         gp.AddWarning(gp.GetMessages())         print >> open(logFile, 'a'), gp.GetMessages()         print gp.GetMessages()     def showGpError():         gp.AddError(gp.GetMessages())         print >> open(logFile, 'a'), gp.GetMessages()         print gp.GetMessages()     def showPyLog(): #just print to the log file!         print >> open(logFile, 'a'), str(time.ctime()) + " - " + message     def showPyMessage():         gp.AddMessage(str(time.ctime()) + " - " + message)         print >> open(logFile, 'a'), str(time.ctime()) + " - " + message         print str(time.ctime()) + " - " + message     def showPyWarning():         gp.AddWarning(str(time.ctime()) + " - " + message)         print >> open(logFile, 'a'), str(time.ctime()) + " - " + message         print str(time.ctime()) + " - " + message     def showPyError():         gp.AddError(str(time.ctime()) + " - " + message)         print >> open(logFile, 'a'), str(time.ctime()) + " - " + message         print str(time.ctime()) + " - " + message     #Specifies the root directory variable, defines the logFile variable, and does some minor error checking...     dateTimeString = str(time.strftime('%Y%m%d%H%M%S'))     scriptName = os.path.split(sys.argv[0])[-1].split(".")[0]     userName = string.lower(os.environ.get("USERNAME")).replace(" ","_").replace(".","_")     tempPathDir = os.environ["TEMP"]     logFileDirectory = r"\\snarf\am\div_lm\ds\gis\tools\log_files"     if os.path.exists(logFileDirectory) == True:         logFile = os.path.join(logFileDirectory, scriptName + "_" + userName + "_" + dateTimeString + ".txt")         try:             print >> open(logFile, 'a'), "Write test successfull!"         except:             logFile = os.path.join(tempPathDir, scriptName + "_" + userName + "_" + dateTimeString + ".txt")      else:         logFile = os.path.join(tempPathDir, scriptName + "_" + userName + "_" + dateTimeString + ".txt")     if os.path.exists(logFile)== True:         os.remove(logFile)         message = "Created log file " + logFile; showPyMessage()     message = "Running " + sys.argv[0]; showPyMessage()     #Process: Attempts to check out a Spatial Analyst license     try:         gp.CheckOutExtension("Spatial")     except:         message = "ERROR: Spatial analyst license is unavailable... Exiting script!"; showPyError(); sys.exit()         #Process: Check out the highest license available     try:         if gp.CheckProduct("ArcView") == "Available":             gp.SetProduct("ArcView")         elif gp.CheckProduct("ArcEditor") == "Available":             gp.SetProduct("ArcEditor")         elif gp.CheckProduct("ArcInfo") == "Available":             gp.SetProduct("ArcInfo")     except:         message = "ERROR: Could not select an ArcGIS license level! Exiting script..."; showPyError(); sys.exit()     message =  "Selected an " + gp.ProductInfo() + " license"; showPyMessage()     #Process: Sets some gp environment variables     gp.overwriteoutput = True     gp.pyramid = "NONE"     gp.rasterStatistics = "NONE"     #Process: Collect the input parameters ##    gridList = r"D:\csny490\usgs_dem10m\dem11746;D:\csny490\usgs_dem10m\dem11747" ##    outputGrid = r"D:\csny490\temp\temp\howaboutthis" ##    processingWorkspace = r"D:\csny490\temp\temp" ##    mosaicMethod = "MAX" ##    tempNoDataValue = "-32000"     gridList = gp.GetParameterAsText(0)     outputGrid = gp.GetParameterAsText(1)     processingWorkspace = gp.GetParameterAsText(2)     mosaicMethod = gp.GetParameterAsText(3)     tempNoDataValue = gp.GetParameterAsText(4)     #Process: Print out the input parameters     message = "INPUT PARAMETERS"; showPyMessage()     message = "----------------"; showPyMessage()     message = "Input Grids          = " + gridList; showPyMessage()     message = "Output Grid          = " + outputGrid; showPyMessage()     message = "Processing Workspace = " + processingWorkspace; showPyMessage()     message = "Mosaic Method        = " + mosaicMethod; showPyMessage()     message = "Temp NoData Value    = " + tempNoDataValue + "\n"; showPyMessage()         #Process: Figure out the maximum extent of all the input grids     message = "Calculating maximum extent of input rasters..."; showPyMessage()     i = 0     gridsToProcessList = gridList.split(";")     for grid in gridsToProcessList:         i = i + 1         dsc = gp.describe(grid)         if i == 1:             xMin = dsc.extent.xmin             yMin = dsc.extent.ymin             xMax = dsc.extent.xmax             yMax = dsc.extent.ymax         else:             if dsc.extent.xmin < xMin:                 xMin = dsc.extent.xmin             if dsc.extent.xmax > xMax:                 xMax = dsc.extent.xmax             if dsc.extent.ymin < yMin:                 yMin = dsc.extent.ymin             if dsc.extent.ymax > yMax:                 yMax = dsc.extent.ymax     gp.extent = str(xMin) + " " + str(yMin) + " " + str(xMax) + " " + str(yMax)     message = "Maximum extent of input rasters is " + str(gp.extent) + "..."; showPyMessage()     #Process: Now build some new grids that have the max extent     maxString = ""     tempGridList = []     i = 0     tempGridDict = {}     for grid in gridsToProcessList:         i = i + 1         message = "Normalizing extent of " + grid + "..."; showPyMessage()         dsc = gp.describe(grid)         if dsc.format != "GRID": #if it aint a grid, make it one             tempConvertGrid = gp.createscratchname("","","RASTER",processingWorkspace)             gp.extent = ""             gp.CopyRaster_management(grid, tempConvertGrid, "", "", "", "", "", "")             tempGridList.append(tempConvertGrid)             somaExp = "con(isnull(" + tempConvertGrid + "), " + str(tempNoDataValue) + ", " + tempConvertGrid + ")"         else:             somaExp = "con(isnull(" + grid + "), " + str(tempNoDataValue) + ", " + grid + ")"         tempGrid = gp.createscratchname("","","RASTER", processingWorkspace)         tempGridList.append(tempGrid)         maxString = maxString + tempGrid + ","         gp.extent = str(xMin) + " " + str(yMin) + " " + str(xMax) + " " + str(yMax)         gp.SingleOutputMapAlgebra_sa(somaExp, tempGrid)              #Process: Max, then put back to null     message = "Mosaicing - This will take a while..."; showPyMessage()     tempGrid = gp.createscratchname("","","RASTER",processingWorkspace)     tempGridList.append(tempGrid)     if mosaicMethod == "MIN":         somaExp = "min(" + maxString + ")"     if mosaicMethod == "MAX":         somaExp = "max(" + maxString + ")"     if mosaicMethod == "MEAN":         somaExp = "mean(" + maxString + ")"     gp.SingleOutputMapAlgebra_sa(somaExp, tempGrid)     somaExp = somaExp = "con(" + tempGrid + " == " + str(tempNoDataValue) + ", setnull(1), " + tempGrid + ")"     if outputGrid.split(".")[-1] in (".bmp",".gif",".img",".jpg",".jp2",".png",".tif") or\        ".gdb" in outputGrid or ".mdb" in outputGrid or ".sde" in outputGrid:         tempMosaicGrid = gp.createscratchname("","","RASTER", processingWorkspace)         tempGridList.append(tempMosaicGrid)         gp.SingleOutputMapAlgebra_sa(somaExp, tempMosaicGrid)         gp.CopyRaster_management(tempMosaicGrid, outputGrid, "", "", "", "", "", "")     else:         gp.SingleOutputMapAlgebra_sa(somaExp, outputGrid)     #Process: Delete all the temp grids     message = "Removing temporay processing grids..."; showPyMessage()     for tempGrid in tempGridList:         try:             gp.Delete_management(tempGrid, "")         except:             message = "WARNING: Failed to delete processing grid " + str(tempGrid) + "..."; showPyWarning()         message = "All done!"; showPyMessage()      except:     message = "\n*** PYTHON ERRORS *** "; showPyMessage()     message = "Python Traceback Info: " + traceback.format_tb(sys.exc_info()[2])[0]; showPyMessage()     message = "Python Error Info: " +  str(sys.exc_type)+ ": " + str(sys.exc_value) + "\n"; showPyMessage() ... 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Yes, I meant that indeed imbeded cursors work, but there is a big difference between working and working fast. Dictionaries are basically a way to build light-speed database tables(s) in memory. Some practical examples using Python dictionaries: http://forums.esri.com/thread.asp?t=275202&f=1729&c=93#948148 (see the .zip file) http://arcscripts.esri.com/details.asp?dbid=16700 ... View more

Here's two different methods to reorder fields via Python: 1. Add some dummy fields, calc over the values (FIELD1_DUMMY = FIELD1_ORIG), delete the original fields, add the fields you want in the order you want, calc over the values (FIELD1_ORIG = FIELD1_DUMMY), then delete the dummy fields. 2. Build a blank  table, add the fields you want to retain in the order you want, then run the append tool to append the original records into the blank table with the reordered fields. As long as the field names/types are exactly the same, use the NO_TEST option, otherwise you have to use the ugly field mapping object which is a real pain. ... View more

Is your data in a geographic projection? If so, you may need to project it into something like stateplane or UTM... ... View more

Take a look at the Near tool: http://webhelp.esri.com/arcgisdesktop/9.3/index.cfm?id=1352&pid=1347&topicname=Near_(Analysis) You must have an ArcInfo license to run it however... ... View more

Sounds as if your subprocess script is failing immediately after it is called. It might be useful for it to write some sort of log file so you can see how far it gets. for calling scripts from a "parent" script I have always used the old fashioned os.spawnv. For example: rootDir = r"D:\temp" script = r"\\snarf\div_lm\script.py" dateTimeStamp = time.strftime('%Y%m%d%H%M%S') for path in sys.path:     if os.path.exists(os.path.join(path, "python.exe")) == True:         pythonExePath = os.path.join(path, "python.exe") parameterList = [pythonExePath, script, rootDir, dateTimeStamp[:8]] os.spawnv(os.P_WAIT, pythonExePath, parameterList) #or to not wait for the spawned process to finish... os.spawnv(os.P_NOWAIT, pythonExePath, parameterList) If you figure out how to get the subprocess module to use a "no wait" method, can you post it? I never found a way to do it... ... View more

Locks often remain for the duration of an ArcMap or ArcCatalog session, even though you aren't currently looking/accessing the FGDB. Also, the gp object does the same thing! Make sure you don't have any ArcWhatever or python.exe running (that are looking or ever looked at one time at the FGDB), and then run your script. ... View more

The fishnet tool is basically a way to make a polygon layer that looks like, well, a fishnet that has adjacent rectangualr (or square) polygons (like a checkerboard). I do a lot of large-dataset processing in Python, and the Fishnet tool is always my step #1 in being able to break up large datasets to get them to work with the ESRI tools. For example: # Description # ----------- # This creates an area of interest feature class, a few buffers of the area of interest, and a fishnet polygon to use for tile-by-tile psudo-parallel processing. # Written for Python version: 2.5.1 (PythonWin) # Written for ArcGIS version: 9.3.1 (should be forward compatible). # Author: Chris Snyder, WA Department of Natural Resources, chris.snyder(at)wadnr.gov # Date created: # Last Updated: 20090923, csny490 try:     #Import system modules and creates the Geoprocessor object (the v9.2 way)     import sys, string, os, glob, shutil, time, traceback, arcgisscripting     gp = arcgisscripting.create(9.3)             #Defines some functions     def showGpMessage():         try:             print >> open(logFile, 'a'), "\n" + gp.GetMessages() + "\n"             print "\n" + gp.GetMessages() + "\n"         except:             pass     def showPyMessage():         try:             print >> open(logFile, 'a'), str(time.ctime()) + " - " + str(message)             print str(time.ctime()) + " - " + str(message)         except:             pass             #Sets a date/time stamp variable in the format yyyymmddhhmmss (example: 20060330132345)     dateTimeStamp = time.strftime('%Y%m%d%H%M%S')     #Specifies the root variable, makes the logFile variable, and does some error checking...     root = sys.argv[1]     if os.path.exists(root)== False:         print "Specified root directory: " + root + " does not exist... Bailing out!"         sys.exit()     scriptName = sys.argv[0].split("\\")[len(sys.argv[0].split("\\")) - 1][0:-3] #Gets the name of the script without the .py extension      logFile = root + "\\log_files\\" + scriptName + "_" + dateTimeStamp[:8] + ".log" #Creates the logFile variable     if os.path.exists(root + "\\log_files") == False:         os.mkdir(root + "\\log_files")     if os.path.exists(logFile)== True:         os.remove(logFile)         message = "Deleting log file with the same name and datestamp... Recreating " + logFile; showPyMessage()     workspaceDir = "overlay_index"     if os.path.exists(root + "\\" + workspaceDir)== False:         message = "Creating layer directory: " + root + "\\" + workspaceDir; showPyMessage()         os.mkdir(root + "\\" + workspaceDir)     #Attempts to check out the highest grade license available...     if gp.CheckProduct("ArcInfo") == "Available":         gp.SetProduct("ArcInfo")     elif gp.CheckProduct("ArcEditor") == "Available":         gp.SetProduct("ArcEditor")     elif gp.CheckProduct("ArcView") == "Available":         gp.SetProduct("ArcView")     else:         messsage =  "No ArcGis licesnses are available... Exiting script!"; showPyMessage(); sys.exit()     message =  "Selected an " + gp.ProductInfo() + " license"; showPyMessage()     #Sets some environment variables        gp.overwriteoutput = True     gp.loghistory = False     sr = 'PROJCS["NAD_1983_HARN_StatePlane_Washington_South_FIPS_4602_Feet",GEOGCS["GCS_North_American_1983_HARN",DATUM["D_North_American_1983_HARN",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Lambert_Conformal_Conic"],PARAMETER["False_Easting",1640416.666666667],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",-120.5],PARAMETER["Standard_Parallel_1",45.83333333333334],PARAMETER["Standard_Parallel_2",47.33333333333334],PARAMETER["Latitude_Of_Origin",45.33333333333334],UNIT["Foot_US",0.3048006096012192]]'     gp.OutputCoordinateSystem = sr     gp.XYTolerance = "0.001 METERS"     gp.XYResolution = "0.0005 METERS"     gp.workspace = root + "\\" + workspaceDir     #Process: Creates a FGDB to hold all the spatial layers     fgdbName = "overlay_index"     fgdbPath = gp.workspace + "\\" + fgdbName + ".gdb"     gp.CreateFileGDB_management(gp.workspace, fgdbName); showGpMessage()     #Process: Makes a FC of the PLS polys we want     plsFC = root + "\\gis_layers\\pls.gdb\\pls"     plsFL = "pls_feature_layer"     gp.MakeFeatureLayer_management(plsFC, plsFL, "SUR_OWN_CD > 0 OR TIM_OWN_CD > 0", "", ""); showGpMessage()     dnrMgmtAllFC = fgdbPath + "\\dnr_mgmt_all"     gp.Dissolve_management(plsFL, dnrMgmtAllFC, "", "", "SINGLE_PART"); showGpMessage()     #Process: Creates a fishnet layer (the basis of the index polygons)     fishnetLine1FC = fgdbPath + "\\fishnet_line1"     dsc = gp.describe(dnrMgmtAllFC)     xMin = dsc.extent.xmin     yMin = dsc.extent.ymin     xMax = dsc.extent.xmax     yMax = dsc.extent.ymax     bufferWidth = 1 #Buffer width expands the the extent of the fishnet by that many map units (to make sure it extends past DNR lands a bit)     numberOfRows = 6     numberOfColumns = 6     gp.CreateFishnet_management(fishnetLine1FC, str(xMin - bufferWidth) + " " + str(yMin - bufferWidth), str(xMin - bufferWidth) + " " + str(yMin), "0", "0", numberOfRows, numberOfColumns, str(xMax + bufferWidth) + " " + str(yMax + bufferWidth), "NO_LABELS", ""); showGpMessage()     fishnet1FC = fgdbPath + "\\fishnet_poly1"     gp.FeatureToPolygon_management(fishnetLine1FC, fishnet1FC, "", "", ""); showGpMessage()     gp.Delete_management(fishnetLine1FC, ""); showGpMessage()     #Process: Creates a 2nd fishnet layer (that is more dense than the original)     fishnetLine2FC = fgdbPath + "\\fishnet_line2"     densificationFactor = 12 #this densification factor ABSOLUTELY NEEDS to be a multiple of 2 (e.g. 2,4,6,8,etc)     gp.CreateFishnet_management(fishnetLine2FC, str(xMin - bufferWidth) + " " + str(yMin - bufferWidth), str(xMin - bufferWidth) + " " + str(yMin), "0", "0", str(numberOfRows * densificationFactor), str(numberOfColumns * densificationFactor), str(xMax + bufferWidth) + " " + str(yMax + bufferWidth), "NO_LABELS", ""); showGpMessage()     fishnet2FC = fgdbPath + "\\fishnet_poly2"     gp.FeatureToPolygon_management(fishnetLine2FC, fishnet2FC, "", "", ""); showGpMessage()     gp.Delete_management(fishnetLine2FC, ""); showGpMessage()     #Process: Updates fishnet1FC with fishnet2FC for specified areas     hcpUnitFC = root + "\\gis_layers\\hcpunit.gdb\\hcpunit"     oesfFC = fgdbPath + "\\oesf"     gp.Select_analysis(hcpUnitFC, oesfFC, "HCPUNIT_ID = 1", "", ""); showGpMessage()     fishnet1FL = "fishnet_1_feature_layer"     gp.MakeFeatureLayer_management(fishnet1FC, fishnet1FL, "", "", ""); showGpMessage()     gp.SelectLayerByLocation_management(fishnet1FL, "INTERSECT", oesfFC, "", "NEW_SELECTION"); showGpMessage()     fishnet2FL = "fishnet_2_feature_layer"     gp.MakeFeatureLayer_management(fishnet2FC, fishnet2FL, "", "", ""); showGpMessage()     gp.SelectLayerByLocation_management(fishnet2FL, "HAVE_THEIR_CENTER_IN", fishnet1FL, "", "NEW_SELECTION"); showGpMessage()     gp.Delete_management(oesfFC, ""); showGpMessage()     fishnetFC = fgdbPath + "\\fishnet_poly"     gp.Update_analysis(fishnet1FC, fishnet2FL, fishnetFC, "BORDERS", ""); showGpMessage()     #Process: Make a line FC version of fishnetFC     fishnetLineFC = fgdbPath + "\\fishnet_lines"     gp.FeatureToLine_management(fishnetFC, fishnetLineFC, "", "NO_ATTRIBUTES"); showGpMessage()         #Process: Unions everything together     union1FC = fgdbPath + "\\union1"     gp.Union_analysis(fishnetFC + ";" + dnrMgmtAllFC, union1FC, "ONLY_FID", "", "GAPS"); showGpMessage()     #BLAH BLAH BLAH - I had to trim this part out to post it to the forum (stupid 10,000 charater limit!!!)     #Process: Compacts the PGDB     gp.Compact_management(fgdbPath); showGpMessage()     #Process: Creates a .txt file that indicates to other scripts how many tiles there are (this is used so that the run_union_master script doesn't have to use the gp and waste memory)        print >> open(root + "\\log_files\\" + "therearethismanytiles_" + str(numberOfTiles) + ".txt", 'a'), "therearethismanytiles_" + str(numberOfTiles)         message = "ALL DONE!"; showPyMessage()     print >> open(root + "\\log_files\\" + scriptName + "_isalldone.txt", 'a'), scriptName + "_isalldone.txt" except:     print >> open(root + "\\log_files\\" + scriptName + "_bombed.txt", 'a'), scriptName + "_bombed.txt"     message = "\n*** LAST GEOPROCESSOR MESSAGE (may not be source of the error)***"; showPyMessage()     showGpMessage()     message = "\n*** PYTHON ERRORS *** "; showPyMessage()     message = "Python Traceback Info: " + traceback.format_tb(sys.exc_info()[2])[0]; showPyMessage()     message = "Python Error Info: " +  str(sys.exc_type)+ ": " + str(sys.exc_value) + "\n"; showPyMessage()     message = "\n*** PYTHON LOCAL VARIABLE LIST ***"; showPyMessage()     variableCounter = 0                          while variableCounter < len(locals()):         message =  str(list(locals())[variableCounter]) + " = " + str(locals()[list(locals())[variableCounter]]); showPyMessage()         variableCounter = variableCounter + 1     showPyMessage() ... 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In v9.3.1 ArcInfo level, the Clip_managment tool does indeed have an option for using a vector featureclass as a psudo-mask (see the "in_template_dataset" parameter). This is tool to use when you have a multi-band image, since the output can be any ESRI-supported format (not just GRID like the ExtractByMask tool). Check it out... ... View more

If workstation fails (try the regionbuffer tool), you might try this in ArcGIS: 1. Convert your lake polys to a line (FeatureToLine tool) 2. Buffer the lines 20m (on both sides, round ends). If the shoreline buffer fails try:    a. Build a fishnet polygon (CreateFishnet tool and then FeatureToPolygon) of sufficient # of cells to break the large contiguous line features into smaller segments. This might take a couple tries to get right.    b Buffer the "chopped up" lines. 3. Erase the buffer from the lake poly. If the erase fails try:    a. Intersect the lake polys with the fishnet you created for the buffers    b. Try the intersect again with the "chopped up" lake polys Generally, the issue is that ArcGIS chokes when you try to do some sort of geoprocessing operation with a feature that has a kajillion vertices. The reason being that all the feature's x,y, pairs need to get loaded into memory in order to do the operation, and often the number of vertrices in a complex feature exceed the limits of the ArcGIS algorithm. The solution is to break your input features into small enough pieces to allow the algorithms to run without maxing out the memory limitations. ... View more