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The area of interest is 1450 km2.

My options are:

50cm newly collected aerial natural color imagery for $28,300

OR

50cm recent archival satellite imagery (includes near IR band) for $20,600

The primary use will be land appraisal, geology(rock outcrop identification), and general GIS work such as digitizing of hydrology and transportation features, orientation maps, etc.

The company hired to fly the area and process the imagery is having various technical difficulties so our product has not yet been delivered.

Recent satellite imagery is available for the entire area. I am aware of the pan-sharpening multispectral imagery process and that aerial image (when available) will be show more detail on the ground but what other pros and cons are there?

Which type of imagery is better for the uses I listed above?

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  • It sounds like it's going to be used for manual interpretation and digitization, not programmatic analysis, is this correct?
    – Radar
    Commented Sep 21, 2011 at 18:49
  • 3
    get the most recent aerial imagery with a quality assurance policy.
    – Mapperz ♦
    Commented Sep 21, 2011 at 19:56
  • @Radar - correct.
    – Jakub Sisak GeoGraphics
    Commented Sep 21, 2011 at 20:33
  • Now that it has been a few years, which product did you go with and did they meet your expectations? Would you have done anything differently?
    – Aaron ♦
    Commented Aug 10, 2014 at 12:42
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    @Aaron - both. Initially the aerial. The image was clear and high resolution but prone to long shadows and similar visual deficiencies such as optical illusions (trees look higher that they are). Aerial looks good as a map underlay but we found it lacking in the "analysis" area so we recently ordered a Pleiades 50cm satellite - new collect. IMHO, the satellite image, which does include NIR, is far more suitable for GIS analysis; tree species and stands are clearer to identify, outcrop pops out, wetlands and water features easy to delineate, no long shadows and optical illusions
    – Jakub Sisak GeoGraphics
    Commented Aug 12, 2014 at 11:58

1 Answer 1

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Some things to consider:

1) Is the aerial imagery going to come stitched together already or are you going to have to manually stitch and post-process each image. You'll probably have to post process the satellite imagery.

2) When was the imagery acquired? For many features (e.g. rock outcrops) you're going to want leaf-off imagery.

3) Was the imagery (both aerial and satellite) aquired about the same time? Are you going to end up with five satellite images in the fall of 2010 and two from winter 2008?

4) What are the cloud cover percentages in the satellite imagery? What is the quality of the aerial imagery (shadows, etc.)?

Essentially, for the purposes you list above you just want some high resolution optical imagery that a GIS tech can look at and digitize from. Both the aerial and satellite imagery at that resolution will be sufficient, assuming the quality is good (low cloud cover, shadows). I'd be most concerned about when the imagery was acquired and how much work it will take to get it post-processed for your GIS people to work with. A $10,000 difference may seem like a lot, but when you add in the man hours to get it in working order the cost is negligible, especially considering the large footprint you're looking to cover.

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  • Both aerial and satellite options are delivered as an ortho-rectified mosaic. No post processing required. Both are mid summer imagery, satellite is a combo of 2011 and 2010.
    – Jakub Sisak GeoGraphics
    Commented Sep 21, 2011 at 20:38
  • It would come down to quality (cloud/shadow) then and the impact of price. It's hard to know without seeing all of the imagery, but I would go with @Mapperz and see if you can get a quality assurance policy from the air photo company.
    – Radar
    Commented Sep 21, 2011 at 22:15
  • The air photo company has already been hired and flown the entire area twice. (They've screwed up the first time) They just for some reason have not delivered the product yet and have all kinds of excuses. I didn't personally place the order but I am not sure whether I've seen any type of quality assurance policy. We just need something and satellite is the only other quick option. i am just not convinced it will be good enough. As for quality the satellite imagery is cloud free quickbird GeoEye combination short shadows.
    – Jakub Sisak GeoGraphics
    Commented Sep 22, 2011 at 0:33
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    Not possible to assess quality of the data with out actually looking at it, but near IR band with satellite imagery will be an advantage for interpretation.
    – Tomek
    Commented Sep 22, 2011 at 8:41

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