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I'm trying to calculate pairwise river distance among 60 XY coordinates in a small region of Mexico with ArcMap 10.2.2. I have defined my projections and projected both my stream network and XY coordinate layers as projected coordinates using the NAD_1983_UTM_Zone_14N since the entire area that I am looking at falls within zone 14 as far as I can tell. I followed all the steps to start a new feature data set, imported my river network and XY layer, built a new network data set, etc. All of that seems to be fine. But when I use the Point Distance tool, specifying my XY layer as the input field and the near objects (since I want the distance between all possible combinations of my points), it always gives me decimal degrees. I also changed the Display setting in the Layer Properties to Kilometers, but that didn't help. I've tried starting from scratch with a blank map, and projecting everything in projected coordinates, but still no luck.

How do I get Point Distance to give KM or miles rather than decimal degrees?

PolyGeo
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zach
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  • That is odd. What coordinate system is the Data Frame using? – jbchurchill Jul 16 '15 at 13:34
  • What is your Geoprocessing>Environments>Output Coordinates set to? – artwork21 Jul 16 '15 at 13:37
  • The Data Frame and Output Coordinates both say NAD_1983_2011_UTM_Zone_14N just as I projected the layers into. – zach Jul 16 '15 at 14:23
  • have you tries a spatial join to see if you also end up with degrees ? – radouxju Jul 16 '15 at 14:47
  • Could you please explain what two things you suggest I join and what this would be telling me? Thanks – zach Jul 16 '15 at 15:00
  • I hope this isn't a stupid question but... How do you know the output is in decimal degrees? According to the tool the output is in whatever units the inputs are in, and the field is just a decimal number, so how do you know you aren't getting what you are supposed to be getting? – Dan Jurgella Jul 16 '15 at 15:23
  • Well, maybe I shouldn't specify decimal degrees. It does not seem to be meters, kilometers, miles, etc. I know this because I manually calculated the distance between just a few of my points in Google Earth and then compared it to the numbers ArcMap is calculating. They are not proportional across sites. Some sites that are about 45km from one another have similar values to other sites that are about 500km from one another. – zach Jul 16 '15 at 15:46
  • I guess the other issue would be whether there is some reason that it just wouldn't be calculating the distances properly. I suppose that could be the issue. All of my points connect to the network and all of my rivers connect to one another downstream. I followed the work flow that I understand to be correct to do the Point to Distance (as I described in my original post). Unless somebody maybe sees something wrong there. – zach Jul 16 '15 at 15:49
  • Did you use the Project tool to convert the data to zone 14 North? If you look at the data extents (in a new arcmap--don't set anything), what are they? – mkennedy Jul 16 '15 at 16:45
  • The extent of my XY data if I add it to a blank/new map is Top 23.409400 ?? Bottom 20.027500 ?? Left -99.394600 ?? Right -96.912400 ??. The river layer is larger because it is of Central America, so it goes outside the bounds of zone 14N. Is that an issue? If so, should I be clipping the river layer to fit zone 14 or using some other coordinate system? – zach Jul 16 '15 at 16:59
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    Your xy data is still in latitude-longitude values aka a geographic coordinate system. You need to define back to NAD83 and use the Project Tool to create a new feature class (shapefile) that using NAD83 UTM 14N. AND don't use NAD83 (2011), that's valid in USA only. Just use NAD 1983. – mkennedy Jul 17 '15 at 09:04
  • If I take the literal wording of your post, you have made the common mistake of confusing the Define Projection tool with the Project tool, as mkennedy's comments point out. See http://gis.stackexchange.com/questions/20572/ When you create your XY layer, it needs to be defined to whatever those coordinate values are, and then you project it to UTM. Define changes definition. Project changes values. You have told Arc that your values are in meters when they're really degrees, so you need to tell it they're degrees and then let it do the math to convert those degrees to meters in UTM. – Chris W Jul 18 '15 at 01:23

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These steps would help to transform shape files from GCS to project coordinate system and ensure the calculation of distance or any other function appear in projected system:

  1. Add the shapefile into frame with projected coordinate in ArcMap.
  2. Make sure the shape file represented in its original coordinate system, for instance, if the file originally with GCS 1984, it should be represented in GCS 1984 so it gets mapped in its real location. This is essential for the next step.
  3. If the feature is a point, use the function "add xy data" to add x and y coordinate and export the table into dbase dbf file. It is important to select the projected coordinate system you want to change to from environment under "output coordinate".
  4. Export the table into dbase dbf file and accept adding it to the frame.
  5. Create new feature based on the dbase dbf file by using the right click command "display xy". Importantly, choose the projected coordinate in accordance with the frame coordinate.
  6. If the feature is line, use the command "Project" from data management tools: projection and transformations. It is important to select the projected coordinate system you want to change to from environment under "output coordinate". Then export the shape file and accept adding it.
MUTAHAR HEZAM
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