Creating ArcMap tools using python scripts: ASCII to Raster batch processing

Recently, I had to process 400 tiles of LiDAR data and find a method that would allow beginners to GIS to achieve the same in the future. For this I decided to create a custom tool in ArcMap which uses a python script to batch process the ASCII files in rasters and then merges these into a final DEM. The users can then start processing this layer for their individual needs.


# Import system modules
import arcpy, os, sys

# Set local variables

inASCII = str(sys.argv[1]) #these variables are linked to the data the user will input when running the tool.
outRaster = str(sys.argv[2])
mergeGeodatabase = str(sys.argv[3])
outputFilename = str(sys.argv[4])
rasterType = "FLOAT"
emptyString = []
britishNationalGridprj = "PROJCS['OSGB 1936 / British National Grid',GEOGCS['OSGB 1936',DATUM['D_OSGB_1936',SPHEROID['Airy_1830',6377563.396,299.3249646]],PRIMEM['Greenwich',0],UNIT['Degree',0.017453292519943295]],PROJECTION['Transverse_Mercator'],PARAMETER['latitude_of_origin',49],PARAMETER['central_meridian',-2],PARAMETER['scale_factor',0.9996012717],PARAMETER['false_easting',400000],PARAMETER['false_northing',-100000],UNIT['Meter',1]]"

#Set path names and convert from windows to python

inASCII_convert = inASCII.replace('\\','//')
outRaster_convert = outRaster.replace('\\','//')
mergeGeodatabase_convert = mergeGeodatabase.replace('\\','//')

#Convert from ascii to raster for each individual file

for files in os.listdir(inASCII_convert):
	if files.endswith(".asc"):
		arcpy.ASCIIToRaster_conversion(inASCII + "//" + files, outRaster + "//" + files.replace(".asc",".tif"), rasterType)
#create string for raster mosaic

for outputs in os.listdir(outRaster_convert):
	if outputs.endswith(".tif"):
		emptyString.append(outRaster_convert + "//" + outputs)
	outputString = ';'.join(emptyString)
#merge all tiffs together
arcpy.MosaicToNewRaster_management(outputString, mergeGeodatabase_convert, outputFilename, britishNationalGridprj ,"16_BIT_UNSIGNED","" , "1","" ,"" )

Creating a tool in ArcMap:

Using ArcCatalog, find the location where you want the toolbox and right-click to select ‘New Toolbox’. From here go to Add -> Script and follow the prompts. When you reach the properties page we need to select four pieces of information the user enters to relate to the 4 inputs that were specified in the script using the sys.argv command. Note these need to be in the same order. Choose a name for the input, select whether it is a input/output in the environment property and then select the type.


The first two relate to folders where all the files are stored, the third to the folder where the output is stored and the forth is for the output file name.

Now you can can run the tool just like any others in toolbox.