Calculate distance to shoreline

[SusannahWoodruff]

Hi,

I have a shapefile of some land and I need to calculate distance to the shoreline from each cell. I can restrict the area on shore so that it doesn't do every point in Alaska! But every time I try to do Euclidean distance to shore it does the opposite. It starts in the water and calculates distance to the coast. I am not sure what I am doing wrong. Any suggestions are welcome! Thanks.

[DanPatterson_Retired]

A picture might help since I can't figure out where your origin locations are  Are they onshore? on the coast? is the water nodata? is the land now a raster?

[SusannahWoodruff]

Hi. The origin "locations" are just a shapefile of the land and I want distance to coast. So I guess the origin locations would be everything NOT exactly on the coast since I want distance to the coast. I did actually also convert the land to a raster. The ocean is just blank white on my map. So I guess no data. Thanks!

[SusannahWoodruff]

It just says no identified features when I click on the water.

[DanPatterson_Retired]

So basically you need to provide some origins from where it  will calculate the distance.  Right now, it is treating your shapefile as the origin and radiating away from it into the 'water'. If you want the reverse, could construct a water raster or use a polyline of your land shapefile to provide the locations.

Euclidean Distance—Help | Documentation 

Understanding Euclidean distance analysis—Help | Documentation 

And you should convert the shapefile to a raster before beginning the analysis since you want control over the analysis extent and cell size

[SusannahWoodruff]

Thanks for the reply. I obviously just don't understand how this works since I have created probably 30 of the wrong outputs in an effort to create the right one. I used Euclidean Distance with no luck although it seems like that it what I want to use. I created what I thought was the correct distance raster (as I mentioned this goes from land out into the water). This is what I think you are calling the water raster. Maybe I need to start more basic since I did create a land raster but that didn't work either, so I must be doing something else wrong. I also tried to use a polyline of my land shapefile, but did that wrong too because nothing happened. And I have been working on this since your last reply--to no avail! Any other suggestions?

[DanPatterson_Retired]

Susannah...

Euclidean distance returns a cell by cell distance from a single location or a bunch of locations denoted by a raster representation of a point, line or polygon feature.

Distance to the shoreline

• from somewhere inland to the shore
• from somewhere in the water to the shore
• from the shoreline into the water
• from the shoreline back inland

 So the question is what are you measuring distance from? and where do you want to measure it into?

You mention the "shoreline"  do you want to measure the distance from the shoreline out into the water? or measure from the shoreline back into the land?  That determines what is the "origin" of the start locations are and the direction of movement.

I said early on... a picture would help .  Draw out on paper what you want, when you have that clear, then you know what is needed.  30 wrong outputs only succeeds at frustration...

[SusannahWoodruff]

Hi,

Thanks for the reply. I am trying to measure from somewhere inland to the shore. I think this actually will suit my needs. I appreciate the replies in helping me figure it out!