Significant results have been obtained from the analyses of ERTS-1 imagery from five cycles over Test Site SR 124 by classical photointerpretation and by an interactive hybrid multispectral information extraction system (GEMS). The synopticity, periodicity and multispectrality of ERTS coverage, available for the first time to LA County planners, have opened up both a new dimensionality in data and offer new capability in preparation of planning inputs. Photointerpretation of ERTS images has produced over 25 overlays at 1:1,000,000 scale depicting regional relations and urban structure in terms of several hundred linear and areal features. To mention only one such result, a possible new fault lineament has been discovered on the northern slope of the Santa Monica mountains in the scene 1144-18015, composited of MSS bands 4, 5, 6,. GEMS analysis of the ERTS products has provided new or improved information in the following planning data categories: urban vegetation; land cover segregation; man-made and natural impact monitoring; urban design; and suitability. ERTS data analysis has allowed planners to establish trends that directly impact planning policies. This new source of information will not only assist current methods to be more efficient, but permits entirely new planning methodologies to be employed

Economy, R.

Mcknight, J. S.

Raje, S.

English

NASA Technical Reports Server

Paper L 18 
'FIRST LOOK' ANALYSES OF FIVE CYCLES OF ERTS-1 IMAGERY OVER 
COUNTY OF LOS ANGELES: ASSESSMENT OF DATA UTILITY FOR URBAN 
DEVELOPMENT AND REGIONAL PLANNING 
S. Raje and R. Economy, General Electric Co,, Space Division, Valley Forge, Penna. and 
J. McKnight", County of Los Angeles, Regional Planning Commission 
ABSTRACT 
Significant results have been obtained from the analyses of ERTS-1 imagery from 
five cycles over Test Site SR 124 by classical photointerpretation and by an interactive 
hybrid multispectral information-extraction system (GEMS). 
The synopticity, periodicity and multispectrality of ERTS coverage, available 
for the first time to LA County planners, have opened up both a new dimensionality in 
data and offer new capability in preparation of planning inputs. 
scale depicting regional relations and urban structure in terms of several hundred 
linear and areal features. To mention only one such result, a possible new fault 
lineament has been discovered on the northern slope of the Santa Monica mountains in 
the scene 114.4-18015, composited of MSS bands 4,5,6. 
in the following planning data categories: Urban Vegetation; Land Cover Segregation; 
Man-made and Natural Impact Monitoring; Urban Design; Land Suitability. 
An ERTS scene, 1036-18010, analyzed by GEMS to provide spectrally-derived 
object class patterns was directly overlaid on a current LA County land use pattern map 
prepared at 1:24,000 scale. The geometric and thematic content of the GEMS-derived 
patterns is sufficient for routine use at the 1:24,000 standard operating scale for county 
and regional planning. The significant point of this converging set of results is that the 
internal, f i e  structure of the inner city has been sub-classlfied spectrally-spatially. 
ERTS data analysis has allowed planners to establish trends that directly impact 
planning policies. For example, detectable grading and new construction sites 
quantitatively indicated the extent, direction and rate or urban expansion which enable 
planners to forecast demand and growth patterns on a regional scale. 
efficient, but permits entirely new planning methodologies to be employed. 
\ 
Photointerpretation of ERTS images has produced over 25 overlays at 1:1,000,000 
GEMS analysis of the ERTS products has provided new or improved information 
This new source of information will not only assist current methods to be more 
* Presented on 3/7/73 as paper L18 at ERTS-1 Symposium. 
1023 
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1. INTRODUCTION 
The County of Los Angeles is populated by 7 million people and covers 4,083 
square miles. Another 13 million people live in the adjacent counties. The Test Site 
SR 124 is an extremely complex environment both physically and socially. It includes 
a vast metropolitan area of some 1500 square miles. Its natural environment includes 
desert 4 high mountains, and two large islands. The camplexity of both the urban and 
the natural environments of the Los Angeles region was aptly pointed out by Professor 
Leonard Bowden respectively in papers L5 and R4 during two sessions at this symposium, 
Los Angeles County is presently involved in the preparation of a Comprehensive 
General Plan as required by California Law. A vast amount of data on a wide range of 
subjects is needed to complete this task successfully Traditional planning operations 
are becoming prohibitively time-consuming and expensive.. Use  of ERTS data in current 
planning operations will provide a less expensive and more timely product, based on 
the findings of this investigation through the 'first look' 
The objectives of this investigation are: i) To evaluate ERTS imagery utility for 
its urban and regional planning applications using the complex Los Angeles area as a 
testing ground and ii) To ascertain the effectiveness of the General Electric Multispectral 
Information System (GEMS) by representative analystshsers operation. 
The project involves three major parties: NASA, the General Electric Company 
and the County of Los Angeles. NASA gathers and preprocesses data at 1:1,000,000, 
1:125,000 and 1:36 000 scales. GE - Space Division analyses the data and conducts the 
investigation jointly with the County Regional Planning Commission who interpret and 
use the data products in its planning program. 
The data extraction methodology basically involves classical photo-interpretation 
by County members on the team and interactive electronic analyses by GE investigators. 
The processes are mutually strengthened by progressive interaction both by remote 
means and in person. Figure 1 depicts the information flow for this study. 
FIGURE 1 Data Analysis Flow 
1024 
2 .  SIGNIFICANT RESULTS 
The results of photointerpretation of ERTS transperancies at the 1:1,000,000 
scale - both black and white as well as standard and non-standard color -cmposites - 
by the County investigators are most succintly communicated in the course of the 
study effort by an ever-increasing series of theme overlays/recognition maps with 
exhaustive annotation and commentary. Here it is appropriate to show a selected 
few of such overlays, as in Figure 2. 
FIGURE 2 An assortment of photoreduced overlays constructed by photo- 
interpretation of ERTS scenes of the LA County Mainland representating 
regional and urban overviews of problems for further analyses. 
The on-golng series of overlays, inaddition to serving 811 orientation reference 
function, also gives a feel for the surprishglyvast data yield capability of the ERTS 
imagery. Our analysis indicates that ERTS data content exceeds the detail shown on 
the standard Army Map Service 1:250,000 scale plastic reflief series of maps. 
102s 
I 
1 
i 
Maior Faults and Fracture Zones: A fairly casual visual inspection df the 
latest COLA ERTS scene 1144-18015, viz. the December 14, 1972 image*, in 
the non-current combination of bands (4,5,6) -- composited for us by the GE- 
Beltsville Photolab -- shows an unusually straight alignment of topographic features 
along the north h c e  of the Santa Monica mountains. This suggested to the Test 
Site Coordinator the possibilitv of a maior new fault zone or lineament. The County 
Geologia, Mr. Arthur Keene, has been assessing this possibility. The ERTS 1 
Symposium Program announced a paper by Professors Pease and Johnson titled, 
"New Fault Lineament in Southern California". The broad pattern they presented in 
the paper G33 in the 3/6/73 session flanks the fault under consideration here, shown 
in the upper left corner o Figure 2 by the dashed line - - -. Corroboration of the 
existence of such a feature would indeed impact land use allocation decesion In the 
vicinity and its confirmed existence would have to be reflected in the mandatory Seismic 
Safety Element of the County General Plan. It should be pointed out too that in the 
imminent future, the Santa Monica Mountains will be increasingly the focus of much 
heated controversy with respect to their land use categorization! 
Moving on to another overlay, the same December 14 print reflects major 
seasonal changes as compared to the previous ERTS scenes with the equivalent center 
point coordinates. Snow covers (upper center block in Figure 2) portions of the 
mountains and desert regions. Areas of new grass growth (upper right corner of 
Figure 2) mostly in the coastal lowlands are also seen for the first time in imagery 
over the Test Site. The simulWeous occurance of Spring and Winter conditions 
illustrate the environmental diversity of Southern California. This is new information 
from direct observation -- valuable to a number of local agencies concerned with water 
management, agriculture, recreation and transportation. It is also needed over the 
longer range by the planning commission to prepare an effective open space and 
recreation plan which takes into account also the scenic quality. This data will enable 
regional recreation planners identify areas of scenic qualiw -- a troublesome problem 
in scenic quality surveys otherwise made conventionally. 
Brush fire burns, not shown in a figure here, show up in the August 1 0  NASA 
product E1018-18010 clearly in a four-some clump in the southeast while the 
October 21 scene E1090-18012 brought out very clearly the Large Sespe burn which 
later could be just discerned under the cloud cover in the NASA itan E1036- 18010 
of August 28, 1972. The fire was known to have been burned during mid-August. The 
brush fires in Southern California form one of the major man-induced 'natural' hazards. 
The large areas burned in a synoptic view should impress any careless fire-bug! 
Incidently, data on topography, geology and fire hazard are used by planners in determin- 
ing the use suitability of land. Suitability judgements are  used, in turn, to allocate space 
for various types of land uses. 
Major agricultural areas: lower left corner square in Figure 2. The very 
considerable variety and complexity of the introduced species of agricultural crops 
within the test stie are readily discernable in all the ERTS scenes on hand todate. A 
regional corroboration of the statement by Lt. Governor Reinecke of California - that 
agriculture forms the biggest industry in the State -- can be made in that County in as 
much as almost lo% of the County area is in agricultural use. As pointed out in the 
mini-paper in the Preliminary Findigs from ERTS Symposium of September 1972 
dealing with Antelope Valley agriculture (area 13 in the overlay) the monitoring of 
1026 
agricultutal disinvestment and rural-urban conversion phenomena will be continued 
in what can be characterized as agricultural sub-systems study. The results of this 
work and the continued effort on water resources analysis from the ERTS imagery via 
the GEMS are reported in the study semi-annual report. 
Major Urban Areas Intensive AWyses: The thrust of the effort underway in this 
investigation since the Preliminary Findings Symposium has been and wil l  continue 
to be on the very cmplex urbanized regions within the Test Site (lower center, Figure 
2). For the first time planners are able to directly observe the entire vast metropolitan 
area in a single scene on a repetitive basis. This experience is absolutely new and 
exciting. Again, we can directly see the shape and the general internal structure of 
the metropolis. An absolutely new data item is the extent and pattern of urban vegetation - 
a powerful clue to the physical and social segragation of the metropolitan area into 
subareas. (Lower right, Figure 2). 
these subareas for effective urban policy making and implementation. 
It is necessary to have an accurate concept of 
Grading and New Construction Sites: Using U-2 aircraft imagery (Figure 3) for 
quasi-ground-truth we have been able to determine that we can identify from ERTS 
imagery (previous December 14 scene) all significant new grading and construction sites. 
This is an emergent capability of major importance since it means we can cheaply 
monitor the extent and direction of new urban expansion and estimate the rate of 
expansion. This means we can now attack head-on a central problem of planning-- 
trend detection. Knowledge of trend is essential for effective land use allocation 
FIGURE 3 One of the Vinten 
70 mm frames from Am-, 
an area 14 X 14 naut. miles 
covering downtown LA - a 
mini-sub-site being most 
intensively studied using the 
GEMS. 
and land use arrangement. The ability to 
identify new large construction frum ERTS 
imagery means that it is now possible to 
monitor the extent, direction and rate or  
urban growth on a nationwide basis using only 
a single source data. Currently contribution 
to what fragmented policy in this field is made 
federally comes from a number of Federal 
Executive Departments: Commerce, Housing 
and Urban Development, Interior.. , formulated 
much as good deal of regional planning is done -- 
by abstraction, extrapolation etc. of data acquired 
from a multitude of sources, Over a disparate 
time period and scale, at considerable expense. 
Monitoring of national urban growth could be done 
more cheaply by means of ERTS observation 
than any other on a very frequent (say, quarterly) 
baais. This monitoritq would almost warrant a 
Super Cabinet charter! 
1027 
i 
Further series of 'urban' overlays, not shown again, were produced for identifying 
from ERTS imagery, using ground truth for discrimination as necessary, industrial 
and commercial districts and nodes -- shape apd size factars help distinguish commercial 
from irdustrial user --; parks, cemeteries and golf courses -- these open space feabres 
are most visible on the October 21 scene composited of bands 4,5 and negative 7. 
Urban Ecolom: The previous overlays help so@ aut the urban ecology of the City. 
The distribution of open spaces, commercial and induetrtal areas above with textured 
difference in the urban pattern define the central city greas. Health concentration of 
urban vegetation defines high quality single family housing areas. These observations 
have been corroborated by a number of speakers during the last coupleof days. Where 
we appear to have made more specific advance in @n analysis of a complex urban area is 
in the further sub-classifkation and delineation of intra-city structural patterns of what 
will be characterized, here as intenaities of cover-use. The problem we have addressed 
to is that defined by Mr. James Wray during the second of his two papers -- dealing 
with the Washington, D. C. metropolitan area over the last decade and half. 
Concurrently with the classical photointerpretation, machine analyses utilizing 
the GEMS have provided greatly enhanced urban analysis capability. An initial experiment 
involved the measurement of the intensity of red band in a color composite image 
(8-28-72). The'resulta were displayed for each quartile of histogram distribution of the 
red intensities. Use of a 35 mm camera and projector -- in Valley Forge and Los 
Angeles, respqctivdy! -- enabled us after much painstaking and patient trackiqg and 
matching to br& this ERTS-GEMS output slide to overlay onto a current land use map of 
scale 1/24,000 which is our operating scale for general planning work. A careful 
examination of the underlay& 1:24,000 scale current land use map indicates that the 
very excitbg result is actually a measure of use intensity--a new data item directly 
obtainable from ERTS and highly significant in urban policy making and implementation. 
Moreover, these analyses have brought out areas that may be inaccurately depicted on 
our current land use map (scale 1:24,000). 
The next series of experiments utilize the GEMS interactive multispectral 
signature acquisition/classification techntques to extract various land coverage classes 
from ERTS color transperapcies. Four and seven theme analyses were performed on ERTS 
image 8-28-72 (scene 1036-18010), bands 4,5,7. The four and seven theme results are 
shown in Figures 4 and 5 respectively 
The seven theme map gives a broad and meaningful ecological pattern of the most 
complex area of central Los Angeles. It separates areas east of the Alameda Street - 
San Fernando Road corridor from those to the west. It broadly separates the west side 
low income area from the middle income area. East of Alameda, two other middle 
income areas (one basically suburban) are broken out. Also major industrial and 
cqrnmercial districts and nodes as well as individual plants are factored out. Major open 
spaces are recognized as well as several dozen major street alignments defined. The 
texture (grain) of the urban pattern is greatly discernable. Finally, the color pattern 
functiope like a "contour map" to give strength to edges and boundries in the ERTS scene. 
1028 
FIGURE 4 Four Theme Computer FIGURE 5 Seven Theme TV Display 
Printout from GEMS of Central Picture off GEMS Screen from Scene 
Los Angeles, portion of the scene E 1036-18010 at minimum zoom, 
from Figure 3 above *. viewing area same as in Figure 4. 
This multiple theme presentation offers the potential for exciting urban design 
capabilities as well as providing the elements of a general design plan. This wodd 
an absolutely new application of ERTS imagery. Even aircraft imagery is seldom 
applied to this use. 
be 
Preliminary GEMS histogram analyses of the Central LA Core indicates that land 
coverage can be segretated via GEMS into as many as 12 themes using ERTS color 
transperancies as inputs. With the completion of the new all digital GEMS/IMAGE 100 
in July of this year, ERTS 4 channel digital data can be processed directly -- yielding 
significantly more land cover segregations. This better theme definition should provide 
even more effective information to the County of Los Angeles Regional Planning Commission. 
A wide range of planning applications are presented above. There is rapidly growing 
interest expressed in ERTS-GEMS results being obtained by COLARPC by a variety of 
secondary users. The county geologist has strongly endorsed the use of ERTS for 
geological analysis. The county forest and fire warden has suggested establishment of 
a test sub-site and has made a helicopter available to project personnel on 3 occasions 
just since January 1, having had a first look at the ERTS imagery on hand. Personnel 
from the agricultural commission have verified the imagery and have repeatedly furnished 
ground truth. Outside the County, the Los Angeles City Depa tment of Water and Power 
and the California State Water Resources Board personnel have furnished the surface 
water acrages as ground truth based on their routine capacity curve measurements of the 
surface acrages. 
1029 
Presentations have been made to: 
1. 
2. 
3. 
4. 
5. 
A presentation is scheduled on March 12 to b e  GPPRB - 17 major county 
department chiefs. Presentations have been requested by: 
Los Angeles County Association of Planning Officials; 
Southern California Association of Governments (SCAG) technical staff; 
Land Use Committee of the Citizen Planning Council; 
Land U s e  Committee of the County General Plan Policy Review Board (GPPRB): 
Conservation and Opm Space Committee of GPPRB. 
1. SCAG, 
2. City of Los Angeles Planning Department. 
The County Parks Department wants to learn if ERTS-GEMS can monitor the 
condition of the larger parks. 
There have been several requests to use ERTS imagery in publications. 
3. CONCLUSIONS 
Initial results show that data from ERTS Lmagery can be of immense benefit 
The impact of natural and man-made in the field of urban and regional plruining 
disasters can be determined timely and inexpensively. 
Data on seasonal changes is available from a single source. The extent, 
direction and rate of urban growth can be effectively monitored. Generalized 
land use can be obtained at low cost and rapidly. Information on intensity of land 
use and urban form, neglected subects in many planning operations, are readily 
available from ERTS imagery. 
A range of exciting opportunities are  opened up in the field of comparative 
urban studies ERTS imagery will be widely useful in regional environmental 
impact analyses. Further analyses of ERTS imagery are certain to extend and 
deepen the benefits to primary users-investigators such as the County of Los Angeles 
Regional Planuing Commission. 
1030 


First look analyses of five cycles of ERTS-1 imagery over County of Los Angeles:  Assessment of data utility for urban development and regional planning

First look analyses of five cycles of ERTS-1 imagery over County of Los Angeles: Assessment of data utility for urban development and regional planning

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