I need to import a scanned photo of the outcrop (geology project) and re-create the grid from which I took plug data- each plug point will be drawn as a shape point file.

The plugs were taken on a metre by metre grid layout. What would be the best way to ensure that the points are evenly spaced on the outcrop photos?- I guess I could mark the points on the scanned photo and then shapefile the marked points.

  • What software would you like to do this in? – djq Jan 1 '13 at 17:43
  • I will be using ArcGIS 10. The idea is to create a kriging surface between the points using Arc Tool Box. – GISWiltshire Jan 1 '13 at 17:46

if you can use arcpy this code could help you :

cur = arcpy.InsertCursor("ticks")

for i in range(int(extent_XMin) ,int( extent_XMax )  , int( interval) ):
    for j in range(int(extent_YMin) , int(extent_YMax) , int( interval) ):
        pt = arcpy.Point(i , j)
        row = cur.newRow()
        row.Shape = pt

this script creates a grid in "ticks"

  • Unfortunately I don't have access to Python on the computer (university restricted access). – GISWiltshire Jan 1 '13 at 18:25
  • any way to do it with vb.net ? arcEngine – Mounaim Nov 6 '13 at 12:25
  • you can do it via geoprocessing in Arcobjects .NET – geogeek Nov 6 '13 at 16:10

To create a regularly spaced point grid, use Create Fishnet (Data Management). In the attached image, I created a 50x50 fishnet grid. However, you can specify any sized grid you would like--just make sure to check the "Create Label Points" box in the tool.

I should also point out that the regularly spaced point grid approach is appropriate for interpolation methods such as local polynomial interpolation that assume samples were taken on a grid. There are other interpolation methods that do not assume samples were taken on a point grid. Methods such as global polynomial interpolation and empirical bayesian kriging do not have such assumptions. In case you are new to kriging, I would highly recommend going through through the ArcGIS Geostatistical Analyst Tutorial, which is very good.

enter image description here


To add points along the feature vertices, use Feature Vertices to Points after you create the fishnet (see below example).

enter image description here

  • Ok awesome- the only thing is the data points- they are on each corner, rather than in the centre. Would fishnet allow me to add to the corners? – GISWiltshire Jan 1 '13 at 18:27
  • @GISWiltshire I edited the post to address your comments. – Aaron Jan 1 '13 at 18:55
  • Great thanks Aaron. I'll give this a go- effectively treating the scanned in photo (cross-sectional view) as a map. Probably pushing the bounds of the function, but do you know if the grid can be angled?- a number of the outcrops are dipping- only at very low angles (max 14). Thanks again. Chris. – GISWiltshire Jan 1 '13 at 19:05
  • Try orienting the fishnet by adding coordinates to the "Y-Axis Coordinate" input in the Fishnet tool. – Aaron Jan 1 '13 at 19:19
  • Your welcome. Good luck! – Aaron Jan 2 '13 at 0:25

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.