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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 shape file the marked points.

Cheers

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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
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2 Answers

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
        cur.insertRow(row)

this script creates a grid in "ticks"

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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 –  AbdelMounaim TAOUSSI Nov 6 '13 at 12:25
    
you can do it via geoprocessing in Arcobjects .NET –  geogeek Nov 6 '13 at 16:10
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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

Edit:

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

enter image description here

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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
    
Cheers Aaron. Thanks for your help. –  GISWiltshire Jan 1 '13 at 21:52
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