[GIS] Updating and exporting XY positions in UTM and WGS84 to spreadsheet using ArcGIS ModelBuilder

arcgis-10.1arcgis-desktopmodelbuilderutmwgs84

On a daily basis I'm editing the geographic positions of various points of a shapefile (corner_XY.shp) by dragging them on my map. When this editing task is done I'm updating the points coordinates in their attribute table column by column by right clicking on the column and calculate geometry.

I have 4 columns: Latitude – Longitude – X_UTM – Y_UTM
Latitude/longitude in WGS84 (format= DD MM SS,SSS) and X_UTM – Y_UTM in WGS84 UTM Zone 15 N.

I'm then exporting the attribute table with the updated fields (Latitude – Longitude – X_UTM – Y_UTM) to an excel spreadsheet to share it with my team.

Exemple of output:

X_UTM        Y_UTM      Latitude            Longitude
596697.989  2276072.78  20° 33' 58.529" N   91° 9' 16.333" W
599675.251  2123364.47  20° 32' 28.838" N   91° 12' 18.624" W
575317.464  2263171.52  20° 23' 51.409" N   91° 6' 35.489" W
....        .....       ......              ......

My project is a projected one in WGS84 UTM Zone 15 N and my shapefile containing the points that I'm moving on a daily basis (corner_XY.shp) is in WGS84 not projected. I'm using ArcGis 10.1.

GOAL: I'm trying to replicate those tasks using the model builder in order to automatically update and export the new position of my points in WGS84 and UTM to an excel spreadsheet.

Best Answer

Once you've done your edits, you could run a model with the following tools:

1.Copy Features. Copy your shapefile to a feature class. This will allow you to use the Alter Field tool in step 3. And it will leave your input intact so you don't have to be afraid of modifying it, and won't bother deleting the fields added in the steps below.

2.Add Geometry Attributes. Check the POINT_X_Y_Z_M Geometry Properties. This will add the latitude and longitude fields if your input's coordinate system is WGS 1984.

3.Alter Field. Use this tool twice to rename the POINT_X and POINT_Y fields created in the previous step to something like LONG and LAT. This tool is new to 10.2.1, I see you have added the ArcGIS 10.1 tag, if you can't upgrade you should use Add Field and Calculate Field to transfer the field values to another field.

4.Add Geometry Attributes again, Check POINT_X_Y_Z_M in Geometry Properties AND specify WGS 1984 UTM Zone 15N in the coordinate system parameter.

The Geometry Attributes tool overwrites field values if the fields it creates already exist, that's why you should change the name of the fields in step 2.

5.Table To Excel to export your rows to an Excel file.

Related Solutions

How to Determine UTM Zone and Hemisphere in a Given Datum

The choice of datum doesn't matter for map making (provided you change datums appropriately, of course). It does matter for transmitting coordinates and sharing data.

To address your last question ("does it even make sense?"), note that UTM is really a coordinate system and as such--in addition to its grid-based zone naming system--it includes a definite datum and unit of measurement as well as a set of projections. What we're talking about here is using its projections (Transverse Mercator (TM) for the low to moderate latitude zones) and its zoning system but possibly changing the datum (and, perhaps, units of measurement). Changing either the datum or the units (or both) is fine, but after that is done the result is not "UTM," strictly speaking. In some applications (e.g., military targeting) it could be dangerously misleading to refer to the resulting (x,y) values as "UTM coordinates," because they will look remarkably like UTM coordinates but might be up to a few hundred meters off. (That can lead to embarrassing things like lost embassies.) Nevertheless, because your principal questions refer to "UTM" in this looser sense, I will also use the term in this way.

UTM is a choice: you can pick any zone to use. It is designed to work within certain accuracy constraints to within 3.5 degrees (longitude) of its meridian at any latitude within the 120 non-polar zones. Because the zones are nominally 6 degrees wide, this allows a 0.5+0.5 = 1 degree longitude overlap with each neighboring zone. Moreover (if you are concerned with map quality foremost and following the UTM system exactly is of lesser importance), the overlap can get larger in the more extreme latitudes (e.g., at 45 degrees the overlap is more than 4 degrees of longitude). Because two (reasonable) datums differ in longitude by at most by 100 meters or so (0.001 degrees), the difference in datum is inconsequential: if you choose a UTM zone based on one datum it will work fine with another.

Once you have allowed yourself the flexibility of changing the datum, you might as well go all the way and create a "custom UTM zone." This is tantamount to dropping UTM altogether (which includes forgetting about the 0.9996 scale factor and origin offsets) and selecting a TM projection suited for the area you are mapping. Within a small area you can do well by placing the meridian of the TM projection through the center of your map and using a scale factor of 1.0000. Choose any convenient origin.

[GIS] Clipping Rasters from Mosaic Dataset in Original Coordinate System

Set the Output Coordinate System environment setting when clipping the raster using Extract by Mask with an input shape file. If you are implementing this in python you should be able to grab the coordinate system from the shape file using the describe method.

Projecting/converting WGS84 World Mercator to WGS84 UTM zone 14N does not require a parameter transformation as they are based on the same geographic coordinate system, if they were dissimilar then this would not work.

Here is a script that will clip a raster mosaic to a shapefile and match the output coordinate system to the shapefile:

import arcpy, sys

InRasterMosaic = sys.argv[1]
InShapeFile = sys.argv[2]
OutRaster = sys.argv[3]

if arcpy.CheckExtension("Spatial") == "Available":
    arcpy.AddMessage("Checking out Spatial")
    arcpy.CheckOutExtension("Spatial")
else:
    arcpy.AddMessage("Unable to get spatial analyst extension")
    sys.exit(0)


desc = arcpy.Describe(InShapeFile)
SR = desc.spatialReference
arcpy.env.outputCoordinateSystem = SR

ExRas = arcpy.sa.ExtractByMask(InRasterMosaic,InShapeFile)
ExRas.save(OutRaster)
arcpy.CheckInExtension("Spatial")

I have tested this and it works! Have a read of Adding a Script Tool, follow those instructions and you can put this into a model.

If the input is in WGS (DD) as stated:

import arcpy, sys, os

InRasterMosaic = sys.argv[1]
InShapeFile = sys.argv[2]
OutRaster = sys.argv[3]

if arcpy.CheckExtension("Spatial") == "Available":
    arcpy.AddMessage("Checking out Spatial")
    arcpy.CheckOutExtension("Spatial")
else:
    arcpy.AddMessage("Unable to get spatial analyst extension")
    sys.exit(0)

# from the geographic extent, get the centre
# of the extent, only the X is required
desc = arcpy.Describe(InShapeFile)
Ext = desc.Extent
CentX = ( Ext.XMin + Ext.XMax ) / 2

# I'm not familiar with North American projections
# so you'll have to put the numbers in for each zone
if CentX < Zone14max:
    ProjSR = arcpy.SpatialReference(32614)
elif CentX < Zone15max:
    ProjSR = arcpy.SpatialReference(32615)
# continue for the required spatial references
else:
    arcpy.AddMessage("Unable to establish coordinate system")
    arcpy.CheckInExtension("Spatial")
    sys.exit(-1)

arcpy.env.outputCoordinateSystem = ProjSR

ExRas = arcpy.sa.ExtractByMask(InRasterMosaic,InShapeFile)
ExRas.save(OutRaster)

arcpy.CheckInExtension("Spatial")

This will need you to make some edits, but will basically do what you're after. Using the centroid of the extent work out which zone it's likely to be in and then use that for the output coordinate system. The numbers are the SRID of the output coordinate system like this one http://spatialreference.org/ref/epsg/32614/

Best Answer

Related Solutions

How to Determine UTM Zone and Hemisphere in a Given Datum

[GIS] Clipping Rasters from Mosaic Dataset in Original Coordinate System

Related Question