MENSURATION POLICY OF THE IMAGARY ANALYSIS SERVICE

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78B05703A000400020009-1
• Release Decision: RIPPUB
• Original Classification: T
• Document Page Count: 5
• Document Creation Date: December 28, 2016
• Document Release Date: December 22, 2003
• Sequence Number: 9
• Publication Date: October 1, 1970
• Content Type: REGULATION

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INTELLIGENCE ACTIVITIES
October 1970
SUBJECT: Mensuration Policy of the Imagery Analysis Service
RECISSION: IAS Instruction No. 51-I, dated June 1968
The attached document has been prepared by an IAS working group and
approved by the IAS Production Board after consultation with NPIC/IEG/PHD.
It contains instructions designed to maintain high standards in the mensura-
tion performed by the Service. It will be distributed to all IAS imagery
analysts and supervisors for their study and retention.
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Distribution:
All IAS Employees
Director
Declass Review by NIMA/DOD
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MENSURATION POLICY OF THE IMAGERY ANALYSIS SERVICE
IAS maintains an internal capability to derive mensural data from
overhead photography in order to insure timely response to CIA requests
for mensuration as well as to support the imagery analysis process. This
requires the availability of various in-house measuring devices, some of
which operate on-line to NPIC's Univac 494 computer. Selection of the
appropriate equipment and techniques to be employed on a particular
mensuration task depends primarily on the requirement, the target, and
the imagery available. For certain specialized mensuration tasks, particu-
larly those requiring photogrammetric expertise, IAS relies on the services
of the Photogrammetry Division/IEG/NPIC.
When extremely important measurements are to be made the following
procedures apply:
I. Consult the Analysis Branch/PHD/IEG to determine if image
motion compensation (IMC) errors or other anomalies are known to
exist in the imagery to be measured.
2. Use on-line mensuration devices unless the imagery covers
appropriately oriented buildings constructed by the Unified Modular
System (UMS). In the latter case filar measuring eyepieces may be
employed for mensuration utilizing UMS derived scale factors. (See
IAR-93011, A Method for Obtaining Highly Accurate Measurements from
Photography of Soviet Buildings, dated May 1969.)
3. Measure on the best available film positives.
4. Average the measurements made at least three times each by
two or more experienced imagery analysts.
5. Whenever possible, these additional steps are to be taken:
a. View the imagery in stereo.
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b. Measure targets of known dimensions as an aid in detecting
significant ephemeral errors and/or equipment malfunctions.
c. Use imagery from two or more missions or, if not avail-
able, use two or more passes from the same mission.
d. Compare IAS measurements with those previously made by
PHD/IEG and considered by them to be reliable.
If the nature of the project does not warrant, or the imagery does not
permit, application of the procedures described above, employ the mensuration
equipment and techniques which are most suitable to the imagery, the technical
data, and the scaling objects available.
ACCURACY STATEMENTS
As no comprehensive statistical analysis of the accuracy of IAS mensura-
tion equipment and techniques has been performed, accuracy statements cannot
be provided for IAS produced measurements. Therefore, measurements for which
accuracy statements are required must be derived by PHD/IEG.
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SPECIALIZED MENSURATION REQUIRING NPIC SUPPORT
The types of mensuration for which IAS requires the photogrammetric
services of PHD/IEG will normally fall into one of the following categories:
1. Mensuration from ground photography.
2. Specialized height, depth, and contour problems.
3. Certain critical measurements from non-satellite imagery.
4. Determination of precise azimuths or geographic coordinates.
5. Mensuration requiring the production of topographic maps or
orthographic projections.
6. Measurements requiring an accuracy statement.
7. Other photogrammetric functions, usually unique in nature.
SUPERVISORY RESPONSIBILITIES
IAS Branch Chiefs are responsible for:
1. Recommending whether a mensuration request should be accomplished
in IAS or sent to PHD/IEG.
2. Reviewing and approving the mensuration techniques undertaken
by imagery analysts under their supervision.
3. Insuring that personnel under their supervision are familiar
with the IAS mensuration policy and that those who perform mensuration
are competent in the use of IAS mensuration equipment.
A Mensuration Advisory Team, chaired by the Technical Advisor, IAS, and
comprised of one representative from each IAS Division, has been established
to provide advice and guidance on unusual mensuration problems.
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